Phenotypic Characterization of Recombinant Marek's Disease Virus in Live Birds Validates Polymorphisms Associated with Virulence

Marek's disease (MD) is a highly infectious lymphoproliferative disease in chickens with a significant economic impact. Mardivirus gallidalpha 2, also known as Marek's disease virus (MDV), is the causative pathogen and has been categorized based on its virulence rank into four pathotypes: mild (m), virulent (v), very virulent (vv), and very virulent plus (vv+). A prior comparative genomics study suggested that several single-nucleotide polymorphisms (SNPs) and genes in the MDV genome are associated with virulence, including nonsynonymous (ns) SNPs in eight open reading frames (ORF): UL22, UL36, UL37, UL41, UL43, R-LORF8, R-LORF7, and ICP4. To validate the contribution of these nsSNPs to virulence, the vv+MDV strain 686 genome was modified by replacing nucleotides with those observed in the vMDV strains. Pathogenicity studies indicated that these substitutions reduced the MD incidence and increased the survival of challenged birds. Furthermore, using the best-fit pathotyping method to rank the virulence, the modified vv+MDV 686 viruses resulted in a pathotype similar to the vvMDV Md5 strain. Thus, these results support our hypothesis that SNPs in one or more of these ORFs are associated with virulence but, as a group, are not sufficient to result in a vMDV pathotype, suggesting that there are additional variants in the MDV genome associated with virulence, which is not surprising given this complex phenotype and our previous finding of additional variants and SNPs associated with virulence.

Rapid sub-nanomolar protein determination in serum using electropolymerized molecularly imprinted polymers (E-MIPs)

Rapid detection of biologicals is important for a range of applications such as medical screening and diagnostics. Antibodies are typically employed for biosensing with high sensitivity and selectivity but can take months to prepare. Here, we investigate electropolymerized molecularly imprinted polymers (E-MIPs), which are produced in minutes as alternative-antibody rapid biosensors for the selective recognition of model proteins bovine haemoglobin (BHb) and bovine serum albumin (BSA). We evaluated two disposable screen-printed electrodes (SPE) designated AT-Au and BT-Au based on their different annealing temperatures. E-MIPs for BHb demonstrated an imprinting factor of 146 : 1 at 1 nM and 12 : 1 at 0.1 nM, showing high effectiveness of E-MIPs compared to their control non-imprinted polymers. The BHb imprinted E-MIP, when tested against BSA as a non-target protein, gave a selectivity factor of 6 : 1 for BHb. Sensor sensitivity directly depended on the nature of the SPE, with AT-Au SPE demonstrating limits of detection in the sub-micromolar range typically achieved for MIPs, while BT-Au SPE exhibited sensitivity in the sub-nanomolar range for target protein. We attribute this to differences in electrode surface area between AT-Au and BT-Au SPEs. The E-MIPs were also tested in calf serum as a model biological medium. The BT-Au SPE MIPs detected the presence of target protein in <10 min with an LOD of 50 pM and LOQ of 100 pM, suggesting their suitability for protein determination in serum with minimal sample preparation. Using electrochemical impedance spectroscopy, we determine equilibrium dissociation constants (KD) for E-MIPs using the Hill-Langmuir adsorption model. KD of BHb E-MIP was determined to be 0.86 ± 0.11 nM.

Development of a multiagency protocol to support people with No Recourse to Public Funds in Wolverhampton (UK)

BACKGROUND

No Recourse to Public Funds (NRPF) status is applied to individuals and families that are subject to immigration control, resulting in them having restricted access to state-funded benefits within England. NRPF is a public health risk as it increases the risk of destitution among vulnerable migrants.

AIMS

The aim of this study was to engage with public and voluntary sector staff within Wolverhampton working with people with a NRPF status to develop and create an easily accessible guide ('protocol') to help facilitate identification of appropriate cross-sector interventions and support.

METHODS

Data were collected via an online survey as well as face-to-face semi-structured interviews with local NRPF stakeholders.

RESULTS

Four themes emerged from the thematic analysis of participant responses: understanding NRPF statuses, varying support requirements, poor communication and awareness of vulnerabilities. Currently, in England, there does not appear to be a standardised localised protocol which can be used to reduce the complexities and confusion encountered by public and voluntary sectors who support people with NRPF status.

CONCLUSION

The findings from this study have allowed the Wolverhampton NRPF to create an online information resource that includes training events to raise the awareness of NRPF, as well as the development of a localised multiagency protocol that has better equipped it to support and safeguard people with NRPF.

Evaluation of electropolymerized molecularly imprinted polymers (E-MIPs) on disposable electrodes for detection of SARS-CoV-2 in saliva

We investigate electropolymerized molecularly imprinted polymers (E-MIPs) for the selective recognition of SARS-CoV-2 whole virus. E-MIPs imprinted with SARS-CoV-2 pseudoparticles (pps) were electrochemically deposited onto screen printed electrodes by reductive electropolymerization, using the water-soluble N-hydroxmethylacrylamide (NHMA) as functional monomer and crosslinked with N,N'-methylenebisacrylamide (MBAm). E-MIPs for SARS-CoV-2 showed selectivity for template SARS-CoV-2 pps, with an imprinting factor of 3:1, and specificity (significance = 0.06) when cross-reacted with other respiratory viruses. E-MIPs detected the presence of SARS-CoV-2 pps in <10 min with a limit of detection of 4.9 log10 pfu/mL, suggesting their suitability for detection of SARS-CoV-2 with minimal sample preparation. Using electrochemical impedance spectroscopy (EIS) and principal component analysis (PCA), the capture of SARS-CoV-2 from real patient saliva samples was also evaluated. Fifteen confirmed COVID-19 positive and nine COVID-19 negative saliva samples were compared against the established loop-mediated isothermal nucleic acid amplification (LAMP) technique used by the UK National Health Service. EIS data demonstrated a PCA discrimination between positive and negative LAMP samples. A threshold real impedance signal (ZRe) ≫ 4000 Ω and a corresponding charge transfer resistance (RCT) ≫ 6000 Ω was indicative of absence of virus (COVID-19 negative) in agreement with values obtained for our control non-imprinted polymer control. A ZRe at or below a threshold value of 600 Ω with a corresponding RCT of <1200 Ω was indicative of a COVID-19 positive sample. The presence of virus was confirmed by treatment of E-MIPs with a SARS-CoV-2 specific monoclonal antibody.

The role of Meq-vIL8 in regulating Marek's disease virus pathogenesis

Marek's disease virus (MDV) is a highly cell-associated oncogenic alphaherpesvirus that causes T cell lymphoma in chickens. MDV-encoded Meq and vIL8 proteins play important roles in transformation and early cytolytic infection, respectively. Previous studies identified a spliced transcript, meq-vIL8, formed by alternative splicing of meq and vIL8 genes in MDV lymphoblastoid tumour cells. To determine the role of Meq-vIL8 in MDV pathogenesis, we generated a recombinant MDV (MDV-meqΔSD) by mutating the splice donor site in the meq gene to abrogate the expression of Meq-vIL8. As expected, our results show that MDV-meqΔSD virus grows similarly to the parental and revertant viruses in cell culture, suggesting that Meq-vIL8 is dispensable for MDV growth in vitro. We further characterized the pathogenic properties of MDV-meqΔSD virus in chickens. Our results show that lack of Meq-vIL8 did not affect virus replication during the early cytolytic phase, as determined by immunohistochemistry analysis and/or viral genome copy number, but significantly enhanced viral DNA load in the late phase of infection in the spleen and brain of infected chickens. In addition, we observed that abrogation of Meq-vIL8 expression reduced the mean death time and increased the prevalence of persistent neurological disease, common features of highly virulent strains of MDV, in inoculated chickens. In conclusion, our study shows that Meq-vIL8 is an important virulence factor of MDV.

Manipulation of Promyelocytic Leukemia Protein Nuclear Bodies by Marek's Disease Virus Encoded US3 Protein Kinase

Promyelocytic leukemia protein nuclear bodies (PML-NBs) are dynamic nuclear structures, shown to be important for herpesvirus replication; however, their role in regulating Marek’s disease virus (MDV) infection has not been studied. MDV is an oncogenic alphaherpesvirus that causes lymphoproliferative disease in chickens. MDV encodes a US3 serine/threonine protein kinase that is important for MDV replication and gene expression. In this study, we studied the role of MDV US3 in regulating PML-NBs. Using an immunofluorescence assay, we found that MDV US3 disrupts PML and SP100 in a kinase dependent manner. In addition, treatment with MG-132 (a proteasome inhibitor) could partially restore the levels of PML and SP100, suggesting that a cellular proteasome dependent degradation pathway is involved in MDV US3 induced disruption of PML and SP100. These findings provide the first evidence for the interplay between MDV proteins and PML-NBs.

Marek's disease virus US3 protein kinase phosphorylates chicken HDAC 1 and 2 and regulates viral replication and pathogenesis

Marek’s disease virus (MDV) is a potent oncogenic alphaherpesvirus that elicits a rapid onset of malignant T-cell lymphomas in chickens. Three MDV types, including GaHV-2 (MDV-1), GaHV-3 (MDV-2) and MeHV-1 (HVT), have been identified and all encode a U_S3 protein kinase. MDV-1 U_S3 is important for efficient virus growth in vitro. To study the role of U_S3 in MDV replication and pathogenicity, we generated an MDV-1 U_S3-null virus and chimeric viruses by replacing MDV-1 U_S3 with MDV-2 or HVT U_S3. Using MD as a natural virus-host model, we showed that both MDV-2 and HVT U_S3 partially rescued the growth deficiency of MDV-1 U_S3-null virus. In addition, deletion of MDV-1 U_S3 attenuated the virus resulting in higher survival rate and lower MDV specific tumor incidence, which could be partially compensated by MDV-2 and HVT U_S3. We also identified chicken histone deacetylase 1 (chHDAC1) as a common U_S3 substrate for all three MDV types while only U_S3 of MDV-1 and MDV-2 phosphorylate chHDAC2. We further determined that U_S3 of MDV-1 and HVT phosphorylate chHDAC1 at serine 406 (S406), while MDV-2 U_S3 phosphorylates S406, S410, and S415. In addition, MDV-1 U_S3 phosphorylates chHDAC2 at S407, while MDV-2 U_S3 targets S407 and S411. Furthermore, biochemical studies show that MDV U_S3 mediated phosphorylation of chHDAC1 and 2 affect their stability, transcriptional regulation activity, and interaction network. Using a class I HDAC specific inhibitor, we showed that MDV U_S3 mediated phosphorylation of chHDAC1 and 2 is involved in regulation of virus replication. Overall, we identified novel substrates for MDV U_S3 and characterized the role of MDV U_S3 in MDV pathogenesis.

Marek’s disease virus (MDV) is a highly contagious and oncogenic avian alphaherpesvirus that causes T-cell lymphomas in chickens. Alphaherpesviruses encoded U_S3 is a multifunctional protein kinase involved in viral replication, apoptosis resistance, and cell-to-cell spread. In this study, we evaluated the importance of MDV U_S3 in regulating MDV replication and pathogenesis in chickens. Our results provide first evidence that MDV U_S3 protein kinase is involved in the replication and pathogenicity of MDV in its natural host. We also identified chicken histone deacetylase 1 and 2 (chHDAC1 and 2) as novel substrates of U_S3 for MDV and characterized the potential impacts of MDV U_S3 induced phosphorylation in their protein stability, transcriptional regulation and protein interactions; to our knowledge, this is the first comparative study of the functions of U_S3 from all three MDV types. This is an important finding towards a better understanding of the functions of alphaherpesviruses encoded U_S3 protein kinase.

Marek's disease virus Meq oncoprotein interacts with chicken HDAC 1 and 2 and mediates their degradation via proteasome dependent pathway

Marek's disease virus (MDV) encodes a basic-leucine zipper (BZIP) protein, Meq, which is considered the major MDV oncoprotein. It has been reported that the oncogenicity of Meq is associated with its interaction with C-terminal binding protein 1 (CtBP), which is also an interaction partner of Epstein-Barr virus encoded EBNA3A and EBNA3C oncoproteins. Since both EBNA3C and CtBP interact with histone deacetylase 1 (HDAC1) and HDAC2, we examined whether Meq shares this interaction with chicken HDAC1 (chHDAC1) and chHDAC2. Using confocal microscopy analysis, we show that Meq co-localizes with chHDAC1 and chHDAC2 in the nuclei of MDV lymphoblastoid tumor cells. In addition, immunoprecipitation assays demonstrate that Meq interacts with chHDAC1 and chHDAC2 in transfected cells and MDV lymphoblastoid tumor cells. Using deletion mutants, interaction domains were mapped to the N-terminal dimerization domain of chHDAC1 and chHDAC2, and the BZIP domain of Meq. Our results further demonstrate that this interaction mediates the degradation of chHDAC1 and chHDAC2 via the proteasome dependent pathway. In addition, our results show that Meq also induces the reduction of global ubiquitinated proteins through a proteasome dependent pathway. In conclusion, our results provide evidence that Meq interacts with chHDAC1 and chHDAC2, and induces their proteasome dependent degradation.

Marek's Disease Virus Cluster 3 miRNAs Restrict Virus' Early Cytolytic Replication and Pathogenesis

Herpesvirus-encoded microRNAs (miRNAs) have been discovered in infected cells; however, lack of a suitable animal model has hampered functional analyses of viral miRNAs in vivo. Marek’s disease virus (MDV) (Gallid alphaherpesvirus 2, GaHV-2) genome contains 14 miRNA precursors, which encode 26 mature miRNAs, grouped into three clusters. In this study, the role of MDV-encoded cluster 3 miRNAs, also known as mdv1-miR-M8-M10, in pathogenesis was evaluated in chickens, the natural host of MDV. Our results show that deletion of cluster 3 miRNAs did not affect virus replication and plaque size in cell culture, but increased early cytolytic replication of MDV in chickens. We also observed that deletion of cluster 3 miRNAs resulted in significantly higher virus reactivation from peripheral blood lymphocytes. In addition, pathogenesis studies showed that deletion of cluster 3 miRNAs resulted in more severe atrophy of lymphoid organs and reduced mean death time, but did not affect the incidence of MDV-associated visceral tumors. We confirmed these results by generating a cluster 3 miRNA revertant virus in which the parental MDV phenotype was restored. To the best of our knowledge, our study provides the first evidence that MDV cluster 3 miRNAs play an important role in modulating MDV pathogenesis.

Deletion of LORF9 but not LORF10 attenuates Marek's disease virus pathogenesis

Marek's disease virus (MDV) genome contains a number of uncharacterized long open reading frames (LORF) and their role in viral pathogenesis has not been fully investigated. Among them, LORF9 (MDV069) and LORF10 (MDV071) are locate at the right terminus of the MDV genome unique long region (U_L). To investigate their role in MDV pathogenesis, we generated LORF9 or LORF10 deletion and revertant viruses. In vitro growth kinetics results show that both LORF9 and LORF10 are not essential for virus growth in cell culture. However, LORF9, but not LORF10, is involved in MDV early cytolytic replication in vivo, as evidenced by limited viral antigen expression in lymphoid organs of LORF9 deletion virus inoculated chickens. MDV genome copy number data further confirmed that LORF9 is important for MDV replication in spleen during early cytolytic phase. Deletion of LORF9 also partially impairs the replication of MDV in feather follicle epithelium (FFE); however, it can still establish latency and transformation. In addition, pathogenesis studies show that deletion of LORF9, but not LORF10, result in significant reduction of MDV induced mortality and slightly reduce MDV associated tumors of inoculated chickens. Importantly, we confirmed these results with the generation of LORF9 and LORF10 revertant viruses that fully restore the phenotypes of parental MDV. In conclusion, our results show that deletion of LORF9, but not LORF10, significantly impair viral replication in lymphoid organs during early cytolytic phase and attenuate Marek's disease virus pathogenesis.

Highly virulent Marek's disease virus strains affect T lymphocyte function and viability of splenocytes in commercial meat-type chickens

In previous studies, we have demonstrated that very virulent plus Marek's disease viruses (vv+MDV) are highly immunosuppressive in commercial meat-type chickens. The specific objectives of this work were to evaluate if vv+MDV immunosuppression (MDV-IS) is induced by reduction of lymphocyte responsiveness and/or viability. Three experiments were conducted to (i) compare vv+MDV 686 with a partially attenuated 686-BAC; (ii) compare vv+MDV strains (648A and 686) with vMDV (GA) and vvMDV (Md5); and (iii) compare chickens vaccinated with Md5-BACΔMEQ and with CVI988 + HVT. In each experiment, spleens were collected at 28-30 days post infection and lymphocytes were isolated and investigated in three ways: their proliferative response to Concanavalin A (ConA) was analysed by MTT proliferation assay; cell death, and expression of CD45 and MHC-I was studied by flow cytometry; and MHC-IA and β-2 microglobulin (B2M) expression was evaluated by real time RT-PCR. Splenocytes of chickens inoculated with vv+MDV were severely impaired to proliferate when exposed to ConA. Furthermore, vv+MDV induced severe splenocyte death that did not occur after infection with v or vvMDV strains. Vaccination with CVI988 + HVT, and at less level with Md5-BACΔMEQ reduced these negative effects. This is in contrast to our previous results in which Md5-BACΔMEQ but not CVI988 + HVT protected against MDV-IS suggesting that although cell death and decrease lymphocyte function seem to be related to MDV virulence and certainly will be associated with immunosuppression, they might not fully explain the previously reported MDV-IS. RESEARCH HIGHLIGHTS vv+MDV induces extensive death in splenocytes in meat-type chickens 28-30 dpi. vv+MDV impairs lymphocyte function in meat-type chickens 28-30 dpi. Vaccination protects against splenocyte death and reduced lymphocyte function. Cell lysis and reduced lymphocyte function do not fully explain MDV-IS.

Effects of combined viral-bacterial challenge with or without supplementation of Saccharomyces cerevisiae boulardii strain CNCM I-1079 on immune upregulation and DMI in beef heifers

Objectives were to determine whether live yeast (LY) supplementation would affect daily dry matter feed intake, body weight (BW), immune, and febrile responses to a viral-bacterial (VB) respiratory challenge. Crossbred heifers (N = 38, BW = 230 ± 16.4 kg) were allocated into a 2 × 2 factorial treatment arrangement: Factor 1 = roughage-based diet with or without LY (Saccharomyces cerevisiae boulardii CNCM I-1079, 62.5 g/hd/d), Factor 2 = VB, intranasal administration of bovine herpesvirus-1 (BHV-1, 2 ×108, PFU) on day 0 and endobronchial inoculation with Mannheimia haemolytica (5.4 × 1010, CFU) on day 3, or intranasal saline administration followed by inoculation with phosphate buffer solution (PBS). Heifers were fed their respective diets for 27 d prior to VB challenge on day 0. Heifers were housed by treatment and group-fed using electronic feedbunks. Thermo-boluses (Medria; Châteaubourg, FR) measured rumen temperature (RUT) at 5-min intervals and rectal temperature and whole blood samples were collected on days 0, 3 to 8, 10, 13, and 15. Data were analyzed using repeated measures in the mixed procedure of SAS with fixed effects of day, diet, inoculation, and their interactions. Animals fed LY exhibited a 16% increase (P = 0.02) in neutrophils relative to CON. Diet × inoculation × day interactions were detected for monocytes and haptoglobin. The VB-LY had the greatest (P < 0.05) concentration of monocytes on day 4, followed by VB-CON which was greater (P < 0.05) than PBS treatments. Haptoglobin concentration was greatest (P < 0.02) for VB-CON on day 5, followed by VB-LY which was greater (P < 0.05) than PBS. Heifers supplemented with LY had less (P < 0.05) haptoglobin production than CON. The VB challenge produced nasal lesions that increased (P < 0.01) with day, reaching a zenith on day 6 with 70% of the nares covered with plaques, and increased (P < 0.05) neutrophils on days 3 to 5. The VB challenge increased RUT (P < 0.05) days 2 to 7 and rectal temperature (P < 0.05) on days 0 and 3 to 6. The increased rectal temperature on day 0 was likely due to increased ambient temperature at time of challenge, as VB heifers were processed after the PBS heifers to avoid contamination. The VB challenge was effective at stimulating immune responses, and RUT was effective for measuring febrile responses. These results indicate that prior LY supplementation altered the leukogram in response to VB challenge, suggestive of increased innate immune response.

Abstract P6-02-04: Ultrasound assessment of residual disease after neoadjuvant chemotherapy (NACT) in node positive triple negative breast cancer (TNBC)

Purpose: To determine accuracy of preoperative ultrasound after NACT to predict residual disease in triple negative breast cancer (TNBC) patients with confirmed axillary nodal metastasis.

Methods: This is an institutional review board approved retrospective study of TNBC patients who received NACT at MD Anderson Cancer Center from January 1999 - June 2015. We identified 327 TNBC patients who had cytologically confirmed breast and nodal disease at baseline evaluation and had preoperative ultrasound evaluation of residual disease. Ultrasound response was divided in tree categories: radiologic complete response (rCR) - complete resolution of the malignant mass); near-rCR - no discernible mass, only an isoechoic flat tumoral bed); and residual disease (RD) - a discernible mass is seen. Axillary ultrasound images were evaluated for lymph node size, cortical thickness and residual morphological type after NAC (type I-VI). Ultrasound breast and axillary findings were compared with final surgical pathology.

Results: In 89 cases (27%), pCR was achieved. 74% (242/327) were unifocal and 26% (86/327) multifocal. Ultrasound rCR was seen in 11% patients (36/327). Of those, 64% (23/36) showed pCR and 36% (13/36) showed residual disease. Ultrasound near-rCR was seen in 26% (84/327). Of those, pCR was seen 49 % (41/84) and residual disease in 51% (43/84). Residual disease was seen in 63% (207/327), 12% (25/207) showed pCR and 88% (182/207) showed residual disease. Regarding axillary lymph nodes, long axis diameter mean was 1.57 cm for patients with pCR and 1.6 cm for no pCR, short axis diameter mean was 0.67 cm for pCR and 0.87 cm for no pCR. Cortical thickness mean was 2 mm for pCR versus 9 mm for no pCR.

Sensitivity of ultrasound for assessment residual disease (ultrasound was considered positive if either breast ultrasound or axillary ultrasound showed residual disease) was 97%. Specificity is 22.47% with a NPV of 74% and PPV of 77%.

Conclusion: Breast and axillary ultrasound performed after NACT showed low specificity but high sensitive to detect residual disease. rCR and near rCR were related with pCR in 64% and 49 % of the cases respectively.

Citation Format: Adrada BE, Valero V, Reddy SM, Barcenas CH, Candelaria R, Wei W, Rauch GM. Ultrasound assessment of residual disease after neoadjuvant chemotherapy (NACT) in node positive triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-02-04.

Abstract OT3-05-04: Phase II study of atezolizumab, cobimetinib, and eribulin in patients with recurrent or metastatic inflammatory breast cancer (IBC)

Background: IBCs that do not completely respond to chemotherapy often have dysregulated immune pathways, and novel therapies are needed to improve outcomes in recurrent/metastatic disease. One-third of IBCs express the atezolizumab target PD-L1, and cobimetinib increases PD-L1 expression; thus, we hypothesize that atezolizumab and cobimetinib may act synergistically in IBC. The FDA-approved agent eribulin is active in IBC and has anti-stem cell activity and can reverse the IBC phenotype of epithelial-to-mesenchymal transition. Hence the use of eribulin as a chemotherapy backbone in combination with other novel agents is well justified.

Trial Design: This single-arm, open-label trial is enrolling patients with recurrent IBC or de novo metastatic IBC that has progressed on at least 1 line of standard chemotherapy. During a 4-week pharmacodynamic window, patients have an upfront biopsy, receive atezolizumab and cobimetinib treatment for 4 weeks, and have a second biopsy. Triple-combination treatment then commences, with standard eribulin dosing. After 4 cycles of eribulin, patients receive maintenance targeted therapy until disease progression or intolerable toxicity.

Eligibility Criteria: Patients with metastatic IBC of any molecular subtype must have measurable disease (per RECIST 1.1) amenable to biopsy. Patients with HER2+ disease must have received both pertuzumab and T-DM1. Patients with treated stable brain metastases are allowed. Patients must have recovered from the acute effects of any prior therapies and have adequate hematologic, organ, and cardiac function. Patients with autoimmune diseases or a history of pneumonitis are ineligible.

Specific Aims: The primary objective is to determine the overall response rate (ORR) of the combination therapy. Secondary objectives include determining the safety and tolerability, clinical benefit rate, response duration, progression-free survival, 2-year overall survival rate and predictive biomarker analyses.

Statistical Methods: The trial will enroll up to 9 patients in its phase I/safety lead-in portion and up to 33 patients total. A Bayesian optimal interval design is used to efficiently determine the maximum tolerated cobimetinib dose in phase I. Patients start cobimetinib at the FDA-approved dose of 60 mg/day with a target toxicity rate is 0.3. Phase II will enroll 24 patients to determine the efficacy of the triple-combination therapy. The historical ORR in metastatic IBC is 10%; our sample size provides 80% power to detect an ORR improvement to 25%.

Accrual: The trial has enrolled 7 patients since its start in August 2017.

Citation Format: Alexander A, Marx AN, Reddy SM, Reuben JM, Le-Petross HC, Lane D, Huang ML, Krishnamurthy S, Gong Y, Gombos DS, Patel N, Tung CI, Allen RC, Kandl TJ, Wu J, Liu S, Patel AB, Futreal A, Wistuba I, Layman RM, Valero V, Tripathy D, Ueno NT, Lim B. Phase II study of atezolizumab, cobimetinib, and eribulin in patients with recurrent or metastatic inflammatory breast cancer (IBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT3-05-04.

Abstract OT1-02-05: A single arm phase II study of adjuvant anti-PD1 (pembrolizumab) in combination with hormonal therapy in patients with hormone receptor (HR)-positive localized inflammatory breast cancer (IBC) who did not achieve a pathological complete response (pCR) to neoadjuvant chemotherapy

Background: The pCR rate to conventional chemotherapy in hormone receptor positive IBC has historically been low (7.4% for HR+ HER2-, and 30% for HR+ HER2+), and despite the use of adjuvant endocrine therapy, the recurrence rate is still as high as 40%. To date, no targeted agent is proven to improve the efficacy of adjuvant endocrine therapy within the IBC population to improve this poor disease free survival (DFS). One plausible reason for the poor efficacy of endocrine therapy is a suppressed immune system, which allows tumor cells to avoid detection despite expression of potential immunogenic surface antigens.

Trial Design: This is a single arm trial that will enroll stage III HR+ IBC patients who have completed neoadjuvant therapy but had residual disease at mastectomy. Enrollment should be before or within 2 months of beginning endocrine therapy. Monitoring of DFS will be done with radiological imaging every 3 cycles (starting at cycle 4) as clinically indicated, per standard of care. Pembrolizumab is given on day 1 of each 21 day cycle for up to 2 years if the disease is controlled, and hormonal therapy will be administered per standard of care.

Eligibility Criteria: Clinical stage 3 IBC ER+/PR+ and HER2 negative patients who completed neoadjuvant chemotherapy and surgery with evidence of residual cancer in the breast or lymph nodes, but be clinically disease-free with good performance status at the start of study. Patients also must have adequate hematologic and organ function, and have recovered from the acute effects from prior treatments.

Specific Aims: The primary objective is to determine the disease free survival (DFS) at 2 years of patients with adjuvant therapy using Pembrolizumab in combination with standard adjuvant hormonal therapy. The secondary objective is to determine the safety and toxicity profile of this combination.

Statistical Methods: With a sample size of 37 patients, assuming that 80% are alive (20% increase from historical data) and disease-free at 2 years, and all patients are followed for &gt;2 years after enrollment with no dropout, a 95% confidence interval around the 2-year estimate of DFS will be generated. DFS will then be compared with the historical control rate of 60% by year 2 using a one-sided exponential MLE test.

Accrual: To date we have enrolled 3 patients since activation in January 2017, and the target enrollment is 37 patients.

Contact information: For more information or to refer a patient, please contact study coordinator, Angela Alexander - aalexand@mdanderson.org

Citation Format: Alexander A, Willey J, Sun H, Parker CA, Marx AN, Wood AL, Reddy SM, Reuben JM, Bassett RL, Le-Petross HT, Krishnamurthy S, Gong Y, Woodward WA, Valero V, Ueno NT, Lim B. A single arm phase II study of adjuvant anti-PD1 (pembrolizumab) in combination with hormonal therapy in patients with hormone receptor (HR)-positive localized inflammatory breast cancer (IBC) who did not achieve a pathological complete response (pCR) to neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-02-05.

Abstract P3-05-08: Lymphoid and myeloid cell characterization of inflammatory breast cancer tumor microenvironment and correlation to pathological complete response

Background: Inflammatory breast cancer (IBC) is an aggressive form of breast cancer with poor response rates to current chemotherapy regimens. With recent successes of immune targeted therapies in other solid tumors and a growing understanding of how the immune tumor microenvironment (TME) affects non-IBC outcomes, we sought to characterize the immune TME in IBC to identify biomarkers of treatment response and potential targets for drug development.

Methods: Pre-treatment core biopsy samples were identified from the MD Anderson Cancer Center IBC tissue bank from patients with stage III and de novo stage IV (with T4d) disease who received neoadjuvant chemotherapy (NAC) with intent to take to mastectomy. Lymphocytes were characterized by stromal tumor infiltrating lymphocyte (sTIL) quantification, CD8 T cell quantification, and T cell receptor sequencing. PD-L1 expression was assessed using DAKO 22C3 clone on tumor and immune cells. Myeloid cells were characterized using a multiplex immunohistochemistry approach, using CD68 and CD163 for macrophage markers, tryptase for mast cell marker, HLA-DR for class II antigen presentation marker, and cytokeratin as tumor marker. Spatial analyses were performed by determining probabilities of finding cell 1 of interest within 20 uM of cell 2 of interest and computing area under the curve for statistical comparison.

Results: 91 patients with stage III (N=62) or de novo stage IV (n=29) disease were identified. Breast cancer subtype included 25 triple negative, 34 HER2+ and 32 HER2-HR+. 86 patients received a mastectomy, of whom 33 (38.4%) patients experienced a pathologic complete response (pCR). sTIL was higher in stage III tumors (11.9 vs 4.8%, p&lt;0.001) and in those having a pCR (13.8 vs 7.3%, p=0.019). CD8 T cell density (available in 48 cases) similarly was higher in stage III patients (360.3 vs 178.8 counts/mm2, p=0.040) and pCR cases (452.3 vs 219.2 counts/mm2, p=0.080) but also higher in HER2+ disease (560.9 for HER2+ vs 239.9 counts/mm2, p=0.087 for TNBC and 153.6 counts/mm2, p=0.005 for HER2-HR+). T cell clonality (available in 32 cases) ranged from 0.004 to 0.242 but showed no correlation to tumor characteristics or response. PD-L1 complete tumor membranous expression was seen in only 1 of 47 cases, whereas PD-L1 positivity on immune cells was seen on 36.2% of cases; neither correlated to response. Myeloid cell assessment (available in 25 cases) showed higher mast cell infiltration in non-pCR cases (63.8 vs 26.8 counts/mm2, p=0.008) and spatial analysis (performed on 10 cases) identified that closer proximity of mast cells to CD8 T cells correlates with response (AUC 6.0 vs 2.2, p=0.017), suggesting a possible immunosuppressive mechanism. HLA-DR analysis demonstrated no difference by response as a single stain marker, but co-localization of HLA-DR with cell type shows higher HLA-DR expression on tumor cells in non-responders (14.6 vs 1.6%, p=0.031).

Conclusions: Higher TIL and CD8 T cell density are correlated with improved responses to NAC in IBC. Mast cell infiltration and HLA-DR expression on tumor cells are inversely correlated to response and suggest possible mechanisms of resistance. Mast cells could present potential therapeutic target in IBC.

Citation Format: Reddy SM, Reuben A, Jiang H, Roszik J, Tetzlaff MT, Reuben J, Wang L, Tsujikawa T, Barua S, Rao A, Villareal L, Wood A, Woodward W, Ueno NT, Krishnamurthy S, Wargo JA, Mittendorf EA. Lymphoid and myeloid cell characterization of inflammatory breast cancer tumor microenvironment and correlation to pathological complete response [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-05-08.

Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients

Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral and gut microbiome of melanoma patients undergoing anti-programmed cell death 1 protein (PD-1) immunotherapy (n = 112). Significant differences were observed in the diversity and composition of the patient gut microbiome of responders versus nonresponders. Analysis of patient fecal microbiome samples (n = 43, 30 responders, 13 nonresponders) showed significantly higher alpha diversity (P < 0.01) and relative abundance of bacteria of the Ruminococcaceae family (P < 0.01) in responding patients. Metagenomic studies revealed functional differences in gut bacteria in responders, including enrichment of anabolic pathways. Immune profiling suggested enhanced systemic and antitumor immunity in responding patients with a favorable gut microbiome as well as in germ-free mice receiving fecal transplants from responding patients. Together, these data have important implications for the treatment of melanoma patients with immune checkpoint inhibitors.

Long-term survival outcomes of triple-receptor negative breast cancer survivors who are disease free at 5 years and relationship with low hormone receptor positivity

Background:

We counsel our triple-negative breast cancer (TNBC) patients that the risk of recurrence is highest in the first 5 years after diagnosis. However, there are limited data with extended follow-up on the frequency, characteristics, and predictors of late events.

Methods:

We queried the MD Anderson Breast Cancer Management System database to identify patients with stage I–III TNBC who were disease free at 5 years from diagnosis. The Kaplan–Meier method was used to estimate yearly recurrence-free interval (RFI), recurrence-free survival (RFS), and distant relapse-free survival (DRFS), as defined by the STEEP criteria. Cox proportional hazards model was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs).

Results:

We identified 873 patients who were disease free at least 5 years from diagnosis with median follow-up of 8.3 years. The 10-year RFI was 97%, RFS 91%, and DRFS 92% the 15-year RFI was 95%, RFS 83%, and DRFS 84%. On a subset of patients with oestrogen receptor and progesterone receptor percentage recorded, low hormone receptor positivity conferred higher risk of late events on multivariable analysis for RFS only (RFI: HR=1.98, 95% CI=0.70–5.62, P-value=0.200; RFS: HR=1.94, 95% CI=1.05–3.56, P-value=0.034; DRFS: HR=1.72, 95% CI=0.92–3.24, P-value=0.091).

Conclusions:

The TNBC survivors who have been disease free for 5 years have a low probability of experiencing recurrence over the subsequent 10 years. Patients with low hormone receptor-positive cancers may have a higher risk of late events as measured by RFS but not by RFI or DRFS.

Abstract P3-16-01: Immune characterization of inflammatory breast cancer and correlation to pathological complete response

Background:

Treatment of inflammatory breast cancer (IBC) includes neoadjuvant chemotherapy (NAC) followed by mastectomy and radiation. Responses are limited however with low pathological complete response (pCR) rates and poor survival. Recent RNA expression studies suggest that activated T cell signaling pathways and immunomodulatory markers such as PD-L1 are associated with a higher pCR rate in IBC; however comprehensive studies of tumor infiltrating lymphocytes (TIL) and protein expression of immunomodulatory molecules are lacking. There is a critical need therefore to study molecular and immune determinants of therapeutic response in IBC, with the goal of identifying biomarkers and actionable strategies to improve treatment outcomes.

Methods:

Baseline core biopsies from 36 IBC patients, 22 with stage III and 14 with stage IV disease were evaluated. Of these, 21 stage III and 10 stage IV patients underwent mastectomy following NAC, the latter for palliative purposes. Tumor subtype distribution was 14 patients with HER2-/HR-, 6 with HER2+/HR-, 11 with HER2-/HR+, and 5 with HER2+/HR+ disease. TIL infiltration in the tumor stroma was quantified on H&E slides based on consensus guidelines as well as by immunohistochemistry (IHC) staining for CD8. PD-L1 expression in the TIL and invasive tumor was evaluated by IHC in tumors with &gt;1%TIL.

Results:

Stromal TIL were found in the invasive tumor on pretreatment biopsies in 26 (72%) patients, with TIL percentages ranging from 1% to 60% (mean=11.6; sd=13.8); of note, 1 patient biopsy sample only had tumor emboli on the tissue block and therefore was not evaluable. Higher TIL infiltrate was noted in stage III versus stage IV disease (mean TIL 11.6% versus 3.5%, p=0.028). Mean TIL infiltrate was 11.5% in HER2-/HR-, 10.0% in HER2+/HR-, 10.4% in HER2+/HR+, and 3.6% in HER2-/HR+ tumors (p=NS). At mastectomy, 7/21 stage III patients and 1/10 stage IV patients achieved a pCR. Mean TIL was 13.4% in the pCR group versus 8.2% in the non-pCR group (p=0.37) CD8 and PD-L1 staining was performed on samples with &gt;1%TIL (n=15, of which 14 samples were available for additional staining). An average of 42% of TIL stained positive for CD8 (range 10-80%). There was no significant relationship between %CD8 and pCR, stage, or receptor status. None of these 14 patients demonstrated membranous PD-L1 positivity but all had focal weak cytoplasmic staining in the lymphocytes.

Conclusions:

Differences exist in the presence of stromal TIL in distinct groups within IBC (stage III versus stage IV disease and across histologic subtypes) and may contribute to differential responses to therapy. When comparing these results to published non-IBC literature (FinHER trial), our IBC patient cohort had lower TIL infiltrate in several histologic subtypes (HER2-/HR- 11.5% vs 25%, p=0.015), HER2+/HR-(10% vs 20%, p=0.10), and HER-/HR+ disease (3.6 vs 7.5%, p=0.01); TIL was comparable for HER2+/HR+ disease. Additional studies are underway (including multiplex analysis of myeloid and lymphoid markers, T cell receptor sequencing, and molecular profiling) in pre-treatment and surgical samples to better understand mechanisms of treatment response and resistance.

Citation Format: Reddy SM, Wargo JA, Reuben A, Reuben J, Woodward W, Ueno N, Mittendorf EA, Krishnamurthy S. Immune characterization of inflammatory breast cancer and correlation to pathological complete response [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-16-01.

Abstract P4-10-09: Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience

Background:

Stage I-III TNBC patients have a high risk of disease relapse during the first 5 years after diagnosis. However, there is limited data on the risk of late relapse in TNBC survivors who are disease free at 5 years or more from diagnosis. We sought to characterize this risk in a cohort of TNBC long-term survivors from a large institutional database.

Methods:

The MD Anderson Breast Cancer Management System database was queried for TNBC survivors who were disease free 5 years or more from diagnosis. Demographic, tumor, and treatment data was extracted. Electronic medical records were searched to confirm pathology reports for invasive breast cancer diagnosis, triple negative receptor status, and hormone receptor percentage (%). The primary and secondary outcomes of interest were relapse free survival (RFS) and distant relapse free survival (DRFS). Patients were censored at time of developing a second primary breast cancer or at last follow-up time for those who were alive during the study. We used ACP-ASCO definition of ER and PR &lt;1% and HER2/neu negative (IHC 0-1 or ratio &lt;2 and average copy number &lt;4) but also included patients with low ER/PR(1-9%) and HER2 normal. Kaplan-Meier analysis was performed to compare RFS and DRFS for the overall population and categorized by ER/PR &lt;1%, and ER/PR 1-9%.

Results:

We identified 1038 patients who had a median follow-up of 8.0 years. Receptor % information was available on 69% of patients, with 78% of them meeting current TNBC definition. From the total cohort of 130, 12.5% suffered event(s) that occurred after 5 years from diagnosis, with 86.2% of them occurring within 5-10 years of diagnosis. The event rate was 16.4% among patients with ER/PR 1-9% versus 11.3% among patients with ER/PR &lt;1%. Table 1 shows RFS and DRFS by year from diagnosis for the entire cohort and categorized by % receptor. 18 patients developed second primary breast cancer as first event and were censored. Of total events recorded, 53(40.8%) were deaths and 77(59.2%) were recurrences, of which 51(66%) were distant and 26(34%) local, of whom 12(46.2%) subsequently developed distant metastases. Among patients who initially presented with distant recurrence, frequencies of initial sites of metastases are shown in Table 2.

Conclusions:

TNBC long term survivors are still at risk for relapse events after 5 years from diagnosis, and it is important to quantity this risk when counseling our patients. Frequency of late events was higher among patients with low hormone receptor positivity. Multivariate modeling of predictors of late recurrence is ongoing.

Table 1: RFS and DRFS by Year from Diagnosis All PatientsER/PR &lt;1%ER/PR 1-9%Year From DiagnosisRFSDRFSRFSDRFSRFSDRFS4-51.01.01.01.01.01.05-60.950.960.940.950.940.956-70.930.940.930.940.910.927-80.900.920.900.920.870.898-90.860.880.870.890.810.849-100.840.870.840.860.800.8310-120.810.840.810.830.800.8312-150.730.780.730.750.670.74

Table 2: Site of Initial Distant RecurrenceSiteN (%)Lung/Pleura28 (54.9)Bone19 (37.3)Distant Lymph Nodes19 (37.3)Liver11 (21.6)Brain/Spinal Cord8 (15.7)Colorectal/Pancreas/Kidney/Adrenal6 (11.7)Other2 (3.9)*Patients presenting with multiple sites of distant recurrence are counted in each category.

Citation Format: Reddy SM, Sinha A, Syed M, Barcenas C, Valero V. Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-10-09.

Phase II study of saracatinib (AZD0530) in patients with previously treated metastatic colorectal cancer

BACKGROUND

Src has a critical role in tumor cell migration and invasion. Increased Src activity has been shown to correlate with disease progression and poor prognosis, suggesting Src could serve as a therapeutic target for kinase inhibition. Saracatinib (AZD0530) is a novel selective oral Src kinase inhibitor.

METHODS

Metastatic colorectal cancer patients who had received one prior treatment and had measurable disease were enrolled in this phase 2 study. Saracatinib was administered at 175 mg by mouth daily for 28 day cycles until dose-limiting toxicity or progression as determined by staging every 2 cycles. The primary endpoint was improvement in 4 month progression-free survival. Design of Thall, Simon, and Estey was used to monitor proportion of patients that were progression free at 4 months. The trial was opened with plan to enroll maximum of 35 patients, with futility assessment every 10 patients.

RESULTS

A total of 10 patients were enrolled between January and November 2007. Further enrollment was stopped due to futility. Median progression-free survival was 7.9 weeks, with all 10 patients showing disease progression following radiographic imaging. Median overall survival was 13.5 months. All patients were deceased by time of analysis. Observed adverse events were notable for a higher than expected number of patients with grade 3 hypophosphatemia (n = 5).

CONCLUSION

Saracatinib is a novel oral Src kinase inhibitor that was well tolerated but failed to meet its primary endpoint of improvement in 4 month progression-free survival as a single agent in previously treated metastatic colorectal cancer patients.

Fungal mediated generation of mammalian metabolites of fenofibrate and enhanced pharmacological activity of the main metabolite fenofibric acid

Different fungi viz. Aspergillus niger NCIM 589, A.ochraceous NCIM 1140, Cunninghamella blakesleeana NCIM 687, C. echinulata NCIM 691, Rhizopus stolonifer NCIM 880, Mucor rouxi MTCC 386, Trichothecium roseum NCIM 1147 were screened for their potential to biotransform anti-hyperlipidemia and anti-hypertriglyceridemia drug, fenofibrate to fenofibric acid, the active metabolite and other mammalian metabolites. Among the fungi screened C. blakesleeana transformed fenofibrate to fenofibric acid and other three metabolites. HPLC, LC-MS/MS analysis and previous reports confirmed the transformation of fenofibrate and metabolites as fenofibric acid (M1), reduced fenofibric acid (M2), reduced fenofibric acid taurine conjugate (M3), reduced fenofibric acid ester glucuronide (M4), the mammalian metabolites reported previously. The results proved the potential of C.blakesleeana NCIM 687 in the production of mammalian phase I (M1 and M2) and phase II (M3 and M4) metabolites in large quantities and also as an in vitro model for drug metabolism studies.

RNA-seq analysis revealed novel genes and signaling pathway associated with disease resistance to avian influenza virus infection in chickens

Avian influenza virus (AIV) is a type A virus of the family Orthomyxoviridae. Avian influenza virus infection can cause significant economic losses to the poultry industry, and raises a great public health threat due to potential host jump from animals to humans. To develop more effective intervention strategies to prevent and control AIV infection in poultry, it is essential to elucidate molecular mechanisms of host response to AIV infection in chickens. The objective of this study was to identify genes and signal pathways associated with resistance to AIV infection in 2 genetically distinct highly inbred chicken lines (Fayoumi, relatively resistant to AIV infection, and Leghorn, susceptible to AIV infection). Three-week-old chickens were inoculated with 10(7) EID50 of low pathogenic H5N3 AIV, and lungs and trachea were harvested 4 d postinoculation. Four cDNA libraries (1 library each for infected and noninfected Leghorn, and infected and noninfected Fayoumi) were prepared from the lung samples and sequenced by Illumina Genome Analyzer II, which yielded a total of 116 million, 75-bp single-end reads. Gene expression levels of all annotated chicken genes were analyzed using CLC Genomics Workbench. DESeq was used to identify differentially expressed transcripts between infected and noninfected birds and between genetic lines (false discovery rate < 0.05 and fold-change > 2). Of the expressed transcripts in a total of 17,108 annotated chicken genes in Ensembl database, 82.44 and 81.40% were identified in Leghorn and Fayoumi birds, respectively. The bioinformatics analysis suggests that the hemoglobin family genes, the functional involvements for oxygen transportation and circulation, and cell adhesion molecule signaling pathway play significant roles in disease resistance to AIV infection in chickens. Further investigation of the roles of these candidate genes and signaling pathways in the regulation of host-AIV interaction can lead new directions for the development of antiviral drugs or vaccines in poultry.

Insertion of reticuloendotheliosis virus long terminal repeat into the genome of CVI988 strain of Marek's disease virus results in enhanced growth and protection

Marek's disease (MD) is a lymphoproliferative disease of chickens caused by serotype 1 MD virus (MDV). Vaccination of commercial poultry has drastically reduced losses from MD, and the poultry industry cannot be sustained without the use of vaccines. Retrovirus insertion into herpesvirus genomes is an efficient process that alters the biological properties of herpesviruses. RM1, a virus derived from the virulent JM strain of MDV, by insertion of the reticuloendotheliosis (REV) long terminal repeat (LTR), was attenuated for oncogenicity but retains properties of the parental virus, such as lymphoid organ atrophy. Here we show that insertion of the REV LTR into the genome of vaccine strain CVI988 resulted in a virus (CVRM) that replicated to higher levels than parental CVI988 in cell culture and that remained apathogenic for chickens. In addition, CVRM showed protection indices similar or superior to those afforded by CVI988 virus in laboratory and field protection trials, indicating that it could be developed as a safe and efficacious vaccine to protect against very virulent plus MDV.

Properties of a meq-deleted rmd5 Marek's disease vaccine: protection against virulent MDV challenge and induction of lymphoid organ atrophy are simultaneously attenuated by serial passage in vitro

We have previously shown that deletion of the meq gene from the genome of Cosmid-cloned rMd5 strain of Marek's disease virus (MDV-1) resulted in loss of transformation and oncogenic capacity of the virus. The rMd5deltaMeq (Meq null) virus has been shown to be an excellent vaccine in maternal antibody positive (MAb+) chickens challenged with a very virulent plus (vv+) strain of MDV, 648A. The only drawback was that it retained its ability to induce bursa and thymus atrophy (BTA) like that of the parental rMd5 in maternal antibody negative (MAb-) chickens. We recently reported that the attenuated Meq null virus did not induce BTA at the 40th cell culture passage onward. Its protective ability against challenge with vv+ MDV, strain 686 was similar to the original virus at the 19th passage in MAb- chickens. In this study, we compared the same series of attenuated meq null viruses in commercial chickens. In commercial chickens with MAb, the attenuated viruses quickly lost protection with increasing cell culture attenuation. These data suggest that although attenuation of these meq null viruses eliminated BTA, it had no influence on their protective efficacy in MAb- chickens. However, in commercial chickens (MAb+), the best protection was provided by the original 19th passage; the attenuated 40th passage was as good as one of the currently commercial CVI988/Rispens vaccine, and it did not induce BTA. Therefore, protection against virulent MDV challenge and induction of lymphoid organ atrophy are simultaneously attenuated by serial passage in vitro.

Deletion of Marek's disease virus large subunit of ribonucleotide reductase impairs virus growth in vitro and in vivo

Marek's disease virus (MDV), a highly cell-associated lymphotropic alphaherpesvirus, is the causative agent of a neoplastic disease in domestic chickens called Marek's disease (MD). In the unique long (UL) region of the MDV genome, open reading frames UL39 and UL40 encode the large and small subunits of the ribonucleotide reductase (RR) enzyme, named RR1 and RR2, respectively. MDV RR is distinguishable from that present in chicken and duck cells by monoclonal antibody T81. Using recombinant DNA technology we have generated a mutant MDV (Md5deltaRR1) in which RR1 was deleted. PCR amplification of the RR gene in Md5deltaRR1-infected duck embryo fibroblasts (DEF) confirmed the deletion of the 2.4 kb RR1 gene with a resultant amplicon of a 640-bp fragment. Restriction enzyme digests with SalI confirmed a UL39 deletion and the absence of gross rearrangement. The biologic characteristics of Md5deltaRR1 virus were studied in vitro and in vivo. The Md5deltaRR1 replicated in DEF, but significantly slower than parental Md5-BAC, suggesting that RR is important but not essential for replication in fibroblasts. In vivo studies, however, showed that the RR1 deletion virus was impaired for its ability to replicate in chickens. Inoculation of specific-pathogen-free (SPF) chickens with Md5deltaRR1 showed the mutant virus is nonpathogenic and does not induce MD in birds. A revertant virus, Md5deltaRR1/R, was generated with the restored phenotype of the parental Md5-BAC in vivo, indicating that RR is essential for replication of the virus in chickens. Protection studies in SPF chickens indicated that the Md5deltaRR1 virus is not a candidate vaccine against MD.

Cloning of a very virulent plus, 686 strain of Marek's disease virus as a bacterial artificial chromosome

Bacterial artificial chromosome (BAC) vectors were first developed to facilitate propagation and manipulation of large DNA fragments. This technology was later used to clone full-length genomes of large DNA viruses to study viral gene function. Marek's disease virus (MDV) is a highly oncogenic herpesvirus that causes rapid induction of T-cell lymphomas in chickens. Based on the virus's ability to cause disease in vaccinated chickens, MDV strains are classified into pathotypes, with the most virulent strains belonging to the very virulent plus (vv+) pathotype. Here we report the construction of BAC clones of 686 (686-BAC), a vv+ strain of MDV. Transfection of DNA isolated from two independent clones into duck embryo fibroblasts resulted in recovery of infectious virus. Pathogenesis studies showed that the BAC-derived 686 viruses were more virulent than Md5, a vv strain of MDV. With the use of a two-step red-mediated mutagenesis process, both copies of viral interleukin 8 (vIL-8) were deleted from the MDV genome, showing that 686-BACs were amenable to mutagenesis techniques. The generation of BAC clones from a vv+ strain of MDV is a significant step toward understanding molecular basis of MDV pathogenesis.

Avian influenza virus investigation in wild bobwhite quail from Texas

The objective of this study was to determine the prevalence of avian influenza viruses (AIV) in bobwhite quail (Colinus virginianus) populations from the rolling plains of Texas, U. S. A. A total of 1320 swab samples (652 tracheal swabs and 668 cloacal swabs) and 44 serum samples were collected from wild-captured or hunter-harvested bobwhite quail from November 2009 to April 2011 at the Rolling Planes Quail Research Ranch, Fisher County, Texas, U. S. A. The presence of AIV in the swabs was determined by real-time reverse-transcription-PCR (rRT-PCR) and all samples positive or suspicious by rRT-PCR were further processed for virus isolation in embryonated chicken eggs. A total of 18 (1.4%) swab samples tested positive for AIV by rRT-PCR (cycle threshold [Ct] values < 35): 13 cloacal swabs (1.9%) and 5 tracheal swabs (0.8%). In addition, 100 (7.6%) swab samples were considered suspicious (Ct values 35.1-40): 69 cloacal swabs (10.3%) and 31 tracheal swabs (4.7%). No virus was isolated from any of the rRT-PCR-positive or suspicious samples tested. Additionally, 44 serum samples were screened for AIV antibodies and were negative. The results presented here indicate low prevalence of AIV in wild populations of bobwhite quail.

Avian influenza virus surveillance in hunter-harvested waterfowl, Texas coast, September 2009-January 2010

Wild waterfowl are considered the natural reservoir of type A influenza viruses, and the migratory nature of many waterfowl species presents a possible vehicle for global dissemination of these infectious agents. In order to fully understand the ecology of influenza viruses, multiyear surveillance efforts are critical, particularly in understudied areas, such as waterfowl wintering areas. Herein we report results obtained during the fifth year ofa 5-yr avian influenza virus (AIV) surveillance project conducted on waterfowl wintering grounds of the Texas Coast. During year 5, the 2009-2010 hunting season (September, November-January), 655 cloacal swabs were collected from hunter-harvested waterfowl and screened for AIV by real-time RT-PCR (rRT-PCR) followed by virus isolation on all positive samples. Molecular methods were used for subtyping all AIV isolates. Sixty-five (9.5%) samples were positive for AIV by rRT-PCR, and 24 (3.7%) AIVs were isolated. Eight different hemagglutinin (H3, 4, 5, 6, 8, 9, 10, and 11) and seven different neuraminidase (N1, 2, 3, 4, 6, 8, and 9) subtypes were identified. This was the first year H8 and H9 were isolated throughout the 5-yr survey. Our results support the fact that continued multiyear surveillance of natural reservoirs, particularly in understudied areas, is needed in order to better understand the ecology of AIVs in nature.

Standardization of a model to study revaccination against Marek's disease under laboratory conditions

Revaccination, the practice of administering Marek's disease (MD) vaccine a second time, has been used in commercial poultry flocks for many years. The rationale is largely anecdotal as the few published reports have failed to provide support for the value of the practice. In the present work, we have standardized a model to study MD revaccination under laboratory conditions. Nine bird experiments were conducted to evaluate homologous revaccination (same vaccine administered twice) and heterologous revaccination (administration of two different vaccines) with various challenge models. Our results demonstrated that heterologous revaccination (with a second vaccine more protective than the first vaccine) but not homologous revaccination provided a beneficial increase in protection. Administration of the first vaccine at 18 days of embryonation followed by a more protective second vaccine at hatch reproduced systematically the benefits of revaccination. In addition, our results show that revaccination protocols might aid in solving major drawbacks associated with various highly protective experimental MD vaccines; that is, lymphoid organ atrophy and residual virulence. Strain RM1 is one of the most protective vaccines against early challenge with highly virulent MD virus but it induces severe lymphoid atrophy in chickens lacking maternal antibodies against MD virus. In this study, strain RM1 did not induce lymphoid organ atrophy when administered as second vaccine in a revaccination protocol. Similarly, strain 648A100/BP5 maintains residual virulence in chickens lacking maternal antibodies against MD virus but did not induce any lesions when used as a second vaccine. Until now, arbitrary revaccination protocols have been occasionally proven useful to the poultry industry. The model developed in this study will allow for a better understanding of this phenomenon and its optimization. A more rational use of this practice will be of great help to control MD outbreaks until better vaccines are available.

Selection of a recombinant Marek's disease virus in vivo through expression of the Marek's EcoRI-Q (Meq)-encoded oncoprotein: characterization of an rMd5-based mutant expressing the Meq of strain RB-1B

Marek's disease (MD) is a highly contagious viral disease of chickens (Gallus gallus domesticus) caused by MD virus (MDV), characterized by paralysis, neurologic signs, and the rapid onset of T-cell lymphomas. MDV-induced T-cell transformation requires a basic leucine zipper protein called Marek's EcoRI-Q-encoded protein (Meq). We have identified mutations in the coding sequence of Meq that correlated with virus pathotype (virulent, very virulent, and very virulent plus). The aim of this study was to determine whether recombinant viruses could be isolated based on Meq expression through in vivo selection. Chicken embryo fibroblasts (CEFs) were cotransfected with an rMd5 strain-based Meq deletion virus (rMd5deltaMeq) and meq loci from strains representing different pathotypes of MDV. Transfected CEFs were inoculated into chickens in two independent studies. We were able to isolate a single recombinant virus, rMDV-1137, in a contact-exposed chicken. rMDV-1137 had recombined two copies of the meq gene of RB-1B and was found to have pathogenicity similar to both RB-1B and rMd5 parental strains. We found the RB-1B- and rMd5-induced lymphomas showed differences in composition and that rMDV-1137-induced lymphomas were intermediate in their composition. We were able to establish cell lines from both RB-1B- (MDCC-UD35, -UD37) and rMDV-1137 (MDCC-UD36, -UD38)-induced, but not rMd5-induced, lymphomas. To date, no rMd5- or parent Md5-transformed T-cell lines have been reported. Our results suggest that 1) a recombinant MDV can be selected on the basis of oncogenicity; 2) changes in Meq sequence seem to affect tumor composition and the ability to establish cell lines; and 3) in addition to meq, other genomic loci affect MDV pathogenicity and oncogenicity.

Cell culture attenuation eliminates rMd5ΔMeq-induced bursal and thymic atrophy and renders the mutant virus as an effective and safe vaccine against Marek's disease

Marek's disease virus (MDV) encodes a basic leucine zipper oncoprotein, Meq, which structurally resembles jun/fos family of transcriptional activators. It has been clearly demonstrated that deletion of Meq results in loss of transformation and oncogenic capacity of MDV. The rMd5ΔMeq virus provided superior protection than CVI988/Rispens vaccine in 15×7 chickens when challenged with a very virulent plus (vv+) strain of MDV, 648A. The rMd5ΔMeq construct was also shown to be an effective vaccine in commercial chickens that were challenged under field conditions by exposure to seeder chicken inoculated with MDV strain 686, a vv+ and arguably the most pathogenic strain of MDV. Although deletion of Meq gene renders the virus non-oncogenic, it still induces lymphoid organ atrophy like that of the parental rMd5, in highly susceptible MDV maternal antibody negative (MAb-) chickens. We have generated 50 cell culture passages of attenuated rMd5ΔMeq viruses and found no significant lymphoid organ atrophy beginning at 40(th) passage onward when compared with the normal control chickens. The protective ability of these attenuated Meq null viruses against challenge with vv+ MDV strain 686 is similar to the original virus at 19(th) passage in maternal antibody negative chickens. The data indicate that attenuation of these Meq null viruses has no influence on their protective efficacy, but eliminated lymphoid organ atrophy and rendered them safe to use even in MAb- chickens, a characteristic that should facilitate commercialization and licensing by vaccine manufacturers.

Development of DIVA (differentiation of infected from vaccinated animals) vaccines utilizing heterologous NA and NS1 protein strategies for the control of triple reassortant H3N2 influenza in turkeys

Since 2003, triple reassortant (TR) swine H3N2 influenza viruses containing gene segments from human, avian, and swine origins have been detected in the U.S. turkey populations. The initial outbreak that occurred involved birds that were vaccinated with the currently available H3 swine- and avian-origin influenza vaccines. Antigenically, all turkey swine-lineage TR H3N2 isolates are closely related to each other but show little or no antigenic cross-reactivity with the avian origin or swine origin influenza vaccine strains that are currently being used in turkey operations. These results call for re-evaluation of currently available influenza vaccines being used in turkey flocks and development of more effective DIVA (differentiation of infected from vaccinated animals) vaccines. In this study, we selected one TR H3N2 strain, A/turkey/OH/313053/04 (H3N2) that showed broad cross reactivity with other recent TR turkey H3N2 isolates, and created NA- and NS-based DIVA vaccines using traditional reassortment as well as reverse genetics methods. Protective efficacy of those vaccines was determined in 2-week-old and 80-week-old breeder turkeys. The reassortant DIVA vaccines significantly reduced the presence of challenge virus in the oviduct of breeder turkeys as well as trachea and cloaca shedding of both young and old breeder turkeys, suggesting that proper vaccination could effectively prevent egg production drop and potential viral contamination of eggs in infected turkeys. Our results demonstrate that the heterologous NA and NS1 DIVA vaccines together with their corresponding serological tests could be useful for the control of TR H3N2 influenza in turkeys.

Evaluation of factors affecting vaccine efficacy of recombinant Marek's disease virus lacking the Meq oncogene in chickens

We previously reported that deletion of the Meq gene from the oncogenic rMd5 virus rendered it apathogenic for chickens. Here we examined multiple factors affecting Marek's disease vaccine efficacy of this nonpathogenic recombinant Meq null rMd5 virus (rMd5deltaMeq). These factors included host genetics (MHC haplotype), strain or dose of challenge virus, vaccine challenge intervals, and maternal antibody status of the vaccinated chicks. Studies on host genetics were carried out in five chicken lines comprising four different MHC B-haplotypes. Results showed that chicken lines tested were highly protected, with protective indexes of 100% (B*2/*15), 94% (B*2/*2), 87% (B*19/*19), and 83% (B*21/*21). At a challenge dose above 8000 plaque-forming units, differences in protection were observed between the two highly virulent strains examined (648A and 686). The interval between vaccination and challenge indicated a protective efficacy from 0 to 2 days varied greatly (12%-82%) after challenge with vv+686, the most virulent virus. Less variation and significant protection began at 3 days post vaccination and reached a maximum at 5 days post vaccination with about 80%-100% protection. Taken together, our results indicate that the factors examined in this study are important for vaccine efficacy and need to be considered in comparative evaluations of vaccines.

Simultaneous detection of avian influenza virus NP and H5 antibodies in chicken sera using a fluorescence microsphere immunoassay

Avian influenza (AI) surveillance in commercial poultry is accomplished by detecting the presence of antibodies to two group-specific antigens, NP and M1, using the agar gel immunodiffusion test. In order to determine the viral subtype responsible for the infection, positive samples must be further subtyped using the hemagglutination inhibition and neuraminidase inhibition tests. These tests are labor intensive and may take up to 4 days, thus slowing down responses to outbreaks. To expedite the subtyping of chicken sera we have developed a multiplex fluorescence microsphere immunoassay (FMIA), which allows for the simultaneous detection and subtyping of chicken sera to H5 influenza viruses. The FMIA was developed using NP (full length) and H5 (HA1 region) proteins expressed in baby hamster kidney cells using a Venezuela equine encephalitis virus replicon system. Both proteins were tagged with 6xHis at the carboxy-end and purified using cobalt-coated agarose beads. Purified H5 protein showed minimal cross-reactivity with anti-H2 serum, while no cross-reactivity was observed with sera to other AI virus (AIV) subtypes and other important poultry viral pathogens. In addition, and as expected, all the AIV sera tested reacted strongly with purified NP protein. Our results indicate that FMIA can be used for rapid subtyping of chicken sera.

Use of avian bornavirus isolates to induce proventricular dilatation disease in conures

The fulfillment of Koch’s postulates shows that the virus causes proventricular dilatation disease in parrots.

Avian bornavirus (ABV) is a newly discovered member of the family Bornaviridae that has been associated with the development of a lethal neurologic syndrome in birds, termed proventricular dilatation disease (PDD). We successfully isolated and characterized ABV from the brains of 8 birds with confirmed PDD. One isolate was passed 6 times in duck embryo fibroblasts, and the infected cells were then injected intramuscularly into 2 healthy Patagonian conures (Cyanoliseus patagonis). Clinical PDD developed in both birds by 66 days postinfection. PDD was confirmed by necropsy and histopathologic examination. Reverse transcription–PCR showed that the inoculated ABV was in the brains of the 2 infected birds. A control bird that received uninfected tissue culture cells remained healthy until it was euthanized at 77 days. Necropsy and histopathologic examinations showed no abnormalities; PCR did not indicate ABV in its brain tissues.

Microbial transformation of albendazole

Screening scale studies were performed to biotransform anthelmintic drug albendazole by using twelve bacterial strains representing six genera and five actinomycetes cultures. Among the cultures studied, Bacillus subtilis MTCC 619, Escherichia coli MTCC 118 and Klebsiella pneumoniae MTCC 109 could transform albendazole to one metabolite whereas, Enterobacter aerogenes NCIM 2695, Klebsiella aerogenes NCIM 2258, Pseudomonas aeruginosa NCIM 2074 and Streptomyces griseus NCIM 2622 could transform albendazole into two metabolites in significant quantities. The transformation of albendazole was identified by HPLC. Based on LC-MS-MS data, the two metabolites were predicted to be albendazole sulfoxide (M1) and albendazole sulfone (M2), the major mammalian metabolites reported previously. Since M1 is active metabolite, the results prove the versatility of microorganisms to perform industrially attractive chemical reactions.

Identification of differentially expressed miRNAs in chicken lung and trachea with avian influenza virus infection by a deep sequencing approach

BACKGROUND

MicroRNAs (miRNAs) play critical roles in a wide spectrum of biological processes and have been shown to be important effectors in the intricate host-pathogen interaction networks. Avian influenza virus (AIV) not only causes significant economic losses in poultry production, but also is of great concern to human health. The objective of this study was to identify miRNAs associated with AIV infections in chickens.

RESULTS

Total RNAs were isolated from lung and trachea of low pathogenic H5N3 infected and non-infected SPF chickens at 4 days post-infection. A total of 278,398 and 340,726 reads were obtained from lung and trachea, respectively. And 377 miRNAs were detected in lungs and 149 in tracheae from a total of 474 distinct chicken miRNAs available at the miRBase, respectively. Seventy-three and thirty-six miRNAs were differentially expressed between infected and non-infected chickens in lungs and tracheae, respectively. There were more miRNAs highly expressed in non-infected tissues than in infected tissues. Interestingly, some of these differentially expressed miRNAs, including miR-146, have been previously reported to be associated with immune-related signal pathways in mammals.

CONCLUSION

To our knowledge, this is the first study on miRNA gene expression in AIV infected chickens using a deep sequencing approach. During AIV infection, many host miRNAs were differentially regulated, supporting the hypothesis that certain miRNAs might be essential in the host-pathogen interactions. Elucidation of the mechanism of these miRNAs on the regulation of host-AIV interaction will lead to the development of new control strategies to prevent or treat AIV infections in poultry.

Characterization of a very virulent Marek's disease virus mutant expressing the pp38 protein from the serotype 1 vaccine strain CVI988/Rispens

Marek's disease virus (MDV), a highly cell-associated oncogenic chicken herpesvirus, causes Marek's disease in domestic chickens. A unique phosphoprotein of MDV, pp38, has previously been associated with the maintenance of transformation in MDV-induced tumor cell lines. However, recently, the biological properties of a deletion mutant virus (rMd5Deltapp38) revealed that pp38 is involved in early cytolytic infection in lymphocytes but not in the induction of tumors. Thus, pp38 is important for early cytolytic infection and not for transformation. The pp38 protein of the MDV serotype 1 vaccine strain CVI988/Rispens differs by one amino acid when compared to the pathogenic strains of MDV. Monoclonal antibody, H19, recognizes all serotype 1 MDV strains except CVI988/Rispens. Previous studies have also shown that the unique pp38 epitope in CVI988/Rispens induced high antibody response. In order to study the role of this epitope in the protective properties of CVI988/Rispens, we generated a mutant rMd5 virus in which the wild type pp38 gene has been substituted with that of CVI988/Rispens (rMd5/pp38CVI). The replication properties of rMd5/pp38CVI, both in vitro and in vivo, and tumor induction were examined. We found that the biological properties of rMd5/pp38CVI were similar to the wild type rMd5 virus with regards to in vivo replication, antibody response and tumor induction. This shows that the pp38 derived from CVI988/Rispens is not involved in protective properties as was previously suggested.

Latency of Marek's disease virus (MDV) in a reticuloendotheliosis virus-transformed T-cell line. II: expression of the latent MDV genome

Marek's disease virus (MDV) is an alphaherpesvirus of chickens that causes the paralysis and rapid lymphoma formation known as Marek's disease. MDV establishes latent infection in activated CD4+ T-cells, and these cells are also the target for transformation. MDV latency has been studied using MDV lymphoma-derived cell lines and T-cells isolated from infected chickens. Each of these models has limitations because MDV-transformed cell lines require the use of oncogenic viruses; conversely, pools of latently infected cells are in relatively low abundance and invariably contain cells undergoing reactivation to lytic infection. In this study we have examined the spontaneous and induced expression of the MDV genome, the effect of genome uptake on cellular proliferation and apoptosis resistance, and differences in cellular surface antigen expression associated with MDV genome uptake in a reticuloendotheliosis virus (REV)-transformed T-cell model. We report that the MDV genome is highly transcribed during this latent infection, and that the expression of Marek's EcoRI-Q-encoded protein (Meq) transcripts is similar to that of MDV-transformed cells, but is somewhat lower than MDV-transformed cells at the protein level. Uptake of the MDV genome was associated with an increased growth rate and resistance to serum starvation-induced apoptosis. Treatment of cells with bromodeoxyuridine induced the expression of MDV lyric antigens in a manner similar to MDV-transformed cells. Uptake of the MDV genome, however, was not consistently associated with alteration ofT-cell surface antigen expression. Overall, our data show that the REV-transformed cell line model for MDV latency mimics many important aspects of latency also observed in MDV-transformed cells and provides an additional tool for examining MDV latent infection.

Latency of Marek's disease virus (MDV) in a reticuloendotheliosis virus-transformed T-cell line. I: uptake and structure of the latent MDV genome

Marek's disease virus (MDV) is an acute transforming alphaherpesvirus of chickens that causes Marek's disease. During the infection of chickens, MDV establishes latency in CD4+ (T-helper) cells, which are also the target of transformation. The study of MDV latency has been limited to the use of MDV tumor-derived cell lines or blood cells isolated from chickens during presumed periods of latent infection. In 1992 Pratt et al. described the uptake of the MDV genome by a reticuloendotheliosis-transformed T-cell line (RECC-CU91). They reported that MDV established latency in CU91 cells, but that MDV genome expression was very limited. In this report we have examined the uptake of oncogenic, recombinant, and vaccine strain MDVs. We report that the entire MDV genome is taken up by CU91 cells, is hypomethylated, and readily reactivates from this latent state in a manner similar to MDV-transformed cell lines. Notably, virus could not be recovered from cell lines harboring vaccine virus CVI988 or the JM102 strain of MDV. Overall these cell lines present a useful model for the further study of MDV latency, particularly for those viruses having mutations that may affect replication or fitness of the virus in vivo. In addition, these cell lines offer an attractive means to study the latency of vaccine viruses, which establish relatively low levels of latent infection in vivo.

A multiplexed immunoassay for detection of antibodies against avian influenza virus

Avian influenza (AI) is a highly contagious disease in poultry and outbreaks can have dramatic economic and health implications. For effective disease surveillance, rapid and sensitive assays are needed to detect antibodies against AI virus (AIV) proteins. In this study, we report the development of a multiplexed fluorescence microsphere immunoassay (FMIA) for detection of antibodies against AIV proteins in poultry. Recombinant nucleoprotein (NP), matrix protein (M1), and non-structural protein 1 (NS1) were expressed using a baculovirus expression system, purified and covalently coupled to fluorescent xMAP microspheres. Using these reagents, a triplex bead assay was developed for the Luminex platform. The assay displayed minimal cross reactivity when screened against a panel of reference sera raised against common avian viruses. For detection of anti-NP antibodies, the sensitivity and specificity of the assay were comparable to a commercially available ELISA. The assay was also employed to investigate the early kinetics of antibody response in chickens infected with AIV. Our results suggest that NP should be the protein of choice when detecting AI infections in commercial chickens, as the immune response was higher and persisted longer than that of M1 and NS1 proteins. This report provides a framework from which a more robust assay could be developed to profile exposure to many AIV subtypes in a single test.

The history of avian influenza

The first description of avian influenza (AI) dates back to 1878 in northern Italy, when Perroncito [Perroncito E. Epizoozia tifoide nei gallinacei. Annali Accad Agri Torino 1878;21:87-126] described a contagious disease of poultry associated with high mortality. The disease, termed "fowl plague", was initially confused with the acute septicemic form of fowl cholera. However, in 1880, soon after its first description, Rivolta and Delprato [as reported by Stubs EL. Fowl pest, In: Biester HE, Devries L, editors. Diseases of poultry. 1st ed. Ames, IO: Iowa State College Press; 1943. p. 493-502] showed it to be different from fowl cholera, based on clinical and pathological properties, and called it Typhus exudatious gallinarum. In 1901, Centanni and Savunzzi [Centanni E, Savonuzzi E, La peste aviaria I & II, Communicazione fatta all'accademia delle scienze mediche e naturali de Ferrara, 1901] determined that fowl plague was caused by a filterable virus; however, it was not until 1955 that the classical fowl plague virus was shown to be a type A influenza virus based on the presence of type A influenza virus type-specific ribonucleoprotein [Schäfer W. Vergleichender sero-immunologische Untersuchungen über die Viren der Influenza und klassischen Geflügelpest. Z Naturf 1955;10b:81-91]. The term fowl plague was substituted by the more appropriate term highly pathogenic avian influenza (HPAI) at the First International Symposium on Avian Influenza [Proceedings of the First International Symposium on Avian Influenza. Beltsville, MD. 1981, Avian Dis 47 (Special Issue) 2003.] and will be used throughout this review when referring to any previously described fowl plague virus.