Microencephaly in fetal piglets following in utero inoculation of Zika virus

Zika virus (ZIKV) is a mosquito-borne flavivirus that became associated with microcephaly in newborns and Guillain-Barré syndrome in adults after its emergence in the Pacific and the Americas in 2015. Newly developed rodent and nonhuman primate models have already revealed important insights into ZIKV-induced neuropathology. Nonhuman primates are phylogenetically closely related to humans and are therefore preferred human surrogates in ZIKV research. However, the use of nonhuman primates, particularly during gestation, raises ethical issues. Considering that pigs also share many anatomical and physiological features with humans, this species may be an attractive alternative human surrogate for ZIKV research. Here, we inoculated 20 porcine fetuses in utero and assessed the effect of ZIKV on brain development 4 weeks later. All inoculated fetuses presented mild to severe neuropathology, characterized by a depletion of neurons in the cerebral cortex. In most cases, neuronal depletion was confined to specific cerebral lobes without affecting brain size, whereas in severe cases a more generalized depletion resulted in microencephaly. Although the virus was widespread in the sows' placenta at the time of necropsy only low levels of viral RNA were detected in fetal brain samples, thereby preventing the identification of primary target cells. Our findings suggest that pigs can be used to study ZIKV-induced neurodevelopmental defects as currently observed in human neonates, varying from stunted brain growth to localized cortical neuronal depletion in the absence of major macroscopic abnormalities.

HBsAg and anti-HCV screening in elderly hospitalized patients of a German tertiary referral centre

BACKGROUND

Elderly patients are under-represented in hepatitis B and C screening approaches, but may be at increased risk for advanced liver disease. We therefore screened a hospitalized elderly population.

MATERIALS AND METHODS

6011 admissions to the department of internal medicine and neurology within one year were screened for HBsAg and anti-HCV (Elecsys(®)-HBsAg and -anti-HCV). Positive anti-HCV results were confirmed with the INNO-LIA™ assay. HCV-RNA was analyzed by real-time PCR in the case of confirmed positive anti-HCV results, HBV-DNA in the confirmed HBsAg positive individuals.

RESULTS

Patient´s mean age (62.4 years) was 19 years above that of the average German population. The confirmed HBsAg prevalence was 0.6 %. 34 % (n = 12/35) of HBsAg positive cases were newly diagnosed, three of them presented with HBV-DNA levels > 2000 IU/mL. The confirmed anti-HCV prevalence was 0.9 %. 14 % (n = 8/56) of anti-HCV positive patients were previously undiagnosed. HCV-RNA was positive in three of them. In newly diagnosed individuals cirrhosis was present in 1/12 of the HBsAg and in 3/8 of the anti-HCV positive individuals. Compared to non-infected controls, the following risk factors were significantly more frequent in infected patients: (i) HBsAg: sexual exposure (20 % vs. 2 %), blood transfusion before 1992 (13 % vs. 6 %), referrals from nursing homes (10 % vs. 1 %). (ii) Anti-HCV: blood transfusion before 1992 (41 % vs. 6 %), IVDU (25 % vs. 0.5 %), organ transplantation (20 % vs. 5 %), hemodialysis (11 % vs. 3 %).

CONCLUSIONS

HBsAg and anti-HCV were underdiagnosed in a senescent population, however, only few cases presented with advanced liver disease. Referrals from nursing homes were at increased risk for HBV infection.

Dietary long chain n-3 polyunsaturated fatty acids prevent allergic sensitization to cow's milk protein in mice

BACKGROUND

Cow's milk allergy is one of the most common food allergies in children and no treatment is available. Dietary lipid composition may affect the susceptibility to develop allergic disease.

OBJECTIVE

Assess whether dietary supplementation with long chain n-3 polyunsaturated fatty acids (n-3 LCPUFA) prevents the establishment of food allergy.

METHODS

Mice were fed a control or fish oil diet before and during oral sensitization with whey. Acute allergic skin response, serum immunoglobulins as well as dendritic cell (DC) and T cell subsets in mesenteric lymph nodes (MLN), spleen and/or small intestine were assessed.

RESULTS

The acute allergic skin response was reduced by more than 50% in sensitized mice fed the fish oil diet compared to the control diet. In addition, anti-whey-IgE and anti-whey-IgG1 levels were decreased in the fish oil group. Serum transfer confirmed that the Th2-type humoral response was suppressed since sera of fish oil fed sensitized mice had a diminished capacity to induce an allergic effector response in naïve recipient mice compared to control sera. Furthermore, the acute skin response was diminished upon passive sensitization in fish oil fed naïve recipient mice. In addition, the percentage of activated Th1 cells was reduced by fish oil in spleen and MLN of sham mice. The percentage of activated Th2 cells was reduced in both sham- and whey-sensitized mice. In contrast, whey-sensitized mice showed an increased percentage of CD11b+CD103+CD8α- DC in MLN in association with enhanced FoxP3+ regulatory T cells (Treg) in spleen and intestine of fish oil fed whey-sensitized mice compared to sham mice.

CONCLUSIONS AND CLINICAL RELEVANCE

Dietary n-3 LCPUFA largely prevented allergic sensitization in a murine model for cow's milk allergy by suppressing the humoral response, enhancing local intestinal and systemic Treg and reducing acute allergic symptoms, suggesting future applications for the primary prevention of food allergy.

Vertical transmission of Rift Valley fever virus without detectable maternal viremia

Rift Valley fever virus (RVFV) is a zoonotic bunyavirus that causes abortions in domesticated ruminants. Sheep breeds exotic to endemic areas are reportedly the most susceptible to RVFV infection. Within the scope of a risk assessment program of The Netherlands, we investigated the susceptibility of a native breed of gestating sheep to RVFV infection. Ewes were infected experimentally during the first, second, or third trimester of gestation. Mortality was high among ewes that developed viremia. Four of 11 inoculated ewes, however, did not develop detectable viremia nor clinical signs and did not seroconvert for immunoglobulin G (IgG) or IgM antibodies. Surprisingly, these ewes were found to contain viral RNA in maternal and fetal organs, and the presence of live virus in fetal organs was demonstrated by virus isolation. We demonstrate that RVFV can be transmitted vertically in the absence of detectable maternal viremia.

Efficacy of three candidate Rift Valley fever vaccines in sheep

Rift Valley fever virus (RVFV) is a mosquito-transmitted Bunyavirus that causes high morbidity and mortality among ruminants and humans. The virus is endemic to the African continent and the Arabian Peninsula and continues to spread into new areas. The explosive nature of RVF outbreaks requires that vaccines provide swift protection after a single vaccination. We recently developed several candidate vaccines and here report their efficacy in lambs within three weeks after a single vaccination. The first vaccine comprises the purified ectodomain of the Gn structural glycoprotein formulated in a water-in-oil adjuvant. The second vaccine is based on a Newcastle disease virus-based vector that produces both RVFV structural glycoproteins Gn and Gc. The third vaccine comprises a recently developed nonspreading RVFV. The latter two vaccines were administered without adjuvant. The inactivated whole virus-based vaccine produced by Onderstepoort Biological Products was used as a positive control. Five out of six mock-vaccinated lambs developed high viremia and fever and one lamb succumbed to the challenge infection. A single vaccination with each vaccine resulted in a neutralizing antibody response within three weeks after vaccination and protected lambs from viremia, pyrexia and mortality.

Rift Valley fever virus immunity provided by a paramyxovirus vaccine vector

Rift Valley fever virus (RVFV) causes recurrent large outbreaks among humans and livestock. Although the virus is currently confined to the African continent and the Arabian Peninsula, there is a growing concern for RVFV incursions into countries with immunologically naïve populations. The RVFV structural glycoproteins Gn and Gc are preferred targets in the development of subunit vaccines that can be used to control future outbreaks. We here report the production of Gn and Gc by a recombinant vaccine strain of the avian paramyxovirus Newcastle disease virus (NDV) and demonstrate that intramuscular vaccination with this experimental NDV-based vector vaccine provides complete protection in mice. We also demonstrate that a single intramuscular vaccination of lambs, the main target species of RVFV, is sufficient to elicit a neutralizing antibody response.

Rift Valley fever virus subunit vaccines confer complete protection against a lethal virus challenge

Rift Valley fever virus (RVFV) is an emerging mosquito-borne virus causing significant morbidity and mortality in livestock and humans. Rift Valley fever is endemic in Africa, but also outside this continent outbreaks have been reported. Here we report the evaluation of two vaccine candidates based on the viral Gn and Gc envelope glycoproteins, both produced in a Drosophila insect cell expression system. Virus-like particles (VLPs) were generated by merely expressing the Gn and Gc glycoproteins. In addition, a soluble form of the Gn ectodomain was expressed and affinity-purified from the insect cell culture supernatant. Both vaccine candidates fully protected mice from a lethal challenge with RVFV. Importantly, absence of the nucleocapsid protein in either vaccine candidate facilitates the differentiation between infected and vaccinated animals using a commercial recombinant nucleocapsid protein-based indirect ELISA.

Biologic diversity of polyomavirus BK genomic sequences: Implications for molecular diagnostic laboratories

Data on polyomavirus genomic diversity has greatly expanded in the past few years. The implications of viral DNA sequence variation on the performance of molecular diagnostic assays have not been systematically examined. 716 BK, 1626 JC, and 73 SV40 virus sequences available in GenBank were aligned using Clustal-X. Five different published BKV PCR assays currently in use at major medical centers were evaluated for primer and probe mismatches with available GenBank sequences. Coverage of naturally occurring BKV strains varied amongst different assay methods. Targeted viral sequences showed major mismatch with primer or probe sequence in up to 30.7% of known BKV strains. BKV subtypes IVa, IVb, and IVc were more prone to this problem, reflecting common use of Type I Dun sequence for assay design. Despite the known polymorphism of this gene, 484 VP-1 sequences with conserved areas potentially suitable for PCR assay design are available. Assay targets in the Large T-antigen and agnogene are less subject to genetic variation, but sequence information corresponding to the latter two genes is available only for 164 and 174 published strains, respectively. Cross reactivity of appropriately selected BKV primers with JCV and SV40 sequences available in current databases was not a significant problem.

Imaging results after CHOP-rituximab followed by 90Y ibritumomab tiuxetan and rituximab (R) in patients with previously-untreated follicular lymphoma (FL)

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Background: There has been some question regarding the predictive value of 111In scans in FL. We report imaging results with fusion PET-CT scans and 111In scans in a single-institution, non-randomized, phase II trial in patients with FL treated with CHOP-R followed by 90Y ibritumomab tiuxetan (Zevalin (Z)) and R. Methods: Eligible patients have CD20 positive FL, Grade 1–3 or transformed, Stage II-IV, no prior treatment with monoclonal antibody or chemotherapy, and symptomatic disease (if grade 1–2). CHOP-R is given every 21 days for 3 cycles. Four weeks after the last dose of CHOP-R, patients receive the Zevalin regimen, which includes 111In imaging and 90Y therapy. One week after Z, patients receive R 375 mg/m2 IV weekly for 4 doses. Bone marrow examination and fusion PET-CT scans are performed at baseline, after CHOP-R, and 12 weeks after Z. The primary endpoint is CR, and responses are reported using the International Working Group (IWG) criteria with the additional requirement of a negative PET scan for CR/CRu. Results: Thirty-six FL patients have been accrued, and 16 patients have completed therapy and follow-up studies. One patient did not have a positive PET scan at baseline. Following therapy, the proportion with a negative PET scan improved from 8 of 15 (53.3%) after CHOP-R to 15 of 15 (100%) after Z. Using IWG criteria in combination with PET scan results, the CR rate increased from 4 of 15 (26.7%) after CHOP-R to 12 of 15 (80%) after Z. Five of 6 patients (83%) with tumor uptake by 111In scan and 7 of 9 (78%) with a 111In scan negative for tumor achieved a CR. Conclusions: There was no significant difference in CR between those patients with 111In tumor uptake versus patients with a negative 111In scan. Functional imaging with PET-CT may be a more sensitive method than CT alone in determining residual disease in FL. This trial continues to accrue patients, and more time is needed to determine the duration of response and time to next therapy.

No significant financial relationships to disclose.

Immunophenotypic and genotypic markers of follicular center cell neoplasia in diffuse large B-cell lymphomas

Diffuse large B-cell lymphomas (DLBCL) are a biologically and clinically heterogeneous entity. Although some DLBCL represent transformation of follicular lymphomas (FL), the proportion that is of follicular center cell (FCC) origin remains uncertain. Immunophenotypic and genotypic markers used to suggest a FCC origin for a lymphoma (bcl-6 and CD10 expression, lack of CD138 expression, bcl-2 rearrangements [R]) or to subdivide DLBCL (bcl-2 expression, bcl-6 R) were therefore investigated in 22 FL and 44 DLBCL using paraffin section immunostains and Southern blot/polymerase chain reaction analysis. All FL tested were bcl-6+ (19) and CD138- (22) with 16/19 also bcl-2 and CD10+ (classic phenotype), one bcl2+, CD10- (grade III) and two bcl2-, CD10+ (grade II or III). Bcl-2R was identified in 4/5 FL-GrI, 3/6 FL-GrII, and 1/3 FL-GrIII. Bcl-6R was found in 0/5, 2/4, and 0/3 FL, respectively. All but 3/41 DLBCL were bcl-6+ with 17/37 also bcl-2+ and CD10+. Three of these cases were also CD138+. Twelve bcl-6+ cases were bcl-2+, CD10-, six bcl-2-, CD10+, and two bcl-2-, CD10-. The three bcl-6- cases were bcl-2+, CD138- and two were CD10+. Bcl-2R was identified in 5/27 DLBCL with 4/5 bcl-2+, 3/4 tested CD10+ and 4/4 bcl-6+. Bcl-6R was identified in 7/26 including three with a classic FL phenotype. The vast majority of DLBCL in this study have an immunophenotype that supports a FCC origin. Although the proportion of DLBCL that co-expressed bcl-6, CD10 and bcl-2 was lower than for the FL, absence of bcl-2 or CD10 may be associated with higher grade FL It is also possible that bcl-6 expression is not completely specific for a FCC origin. Only a minority of cases suggested postfollicular differentiation. Only a minority of DLBCL show bcl-2R, suggesting that many have a different molecular pathogenesis than most low-grade FL. Bcl-6R did not exclude a FCC origin.

Genetic heterogeneity in hereditary breast cancer: role of BRCA1 and BRCA2

The common hereditary forms of breast cancer have been largely attributed to the inheritance of mutations in the BRCA1 or BRCA2 genes. However, it is not yet clear what proportion of hereditary breast cancer is explained by BRCA1 and BRCA2 or by some other unidentified susceptibility gene(s). We describe the proportion of hereditary breast cancer explained by BRCA1 or BRCA2 in a sample of North American hereditary breast cancers and assess the evidence for additional susceptibility genes that may confer hereditary breast or ovarian cancer risk. Twenty-three families were identified through two high-risk breast cancer research programs. Genetic analysis was undertaken to establish linkage between the breast or ovarian cancer cases and markers on chromosomes 17q (BRCA1) and 13q (BRCA2). Mutation analysis in the BRCA1 and BRCA2 genes was also undertaken in all families. The pattern of hereditary cancer in 14 (61%) of the 23 families studied was attributed to BRCA1 by a combination of linkage and mutation analyses. No families were attributed to BRCA2. Five families (22%) provided evidence against linkage to both BRCA1 and BRCA2. No BRCA1 or BRCA2 mutations were detected in these five families. The BRCA1 or BRCA2 status of four families (17%) could not be determined. BRCA1 and BRCA2 probably explain the majority of hereditary breast cancer that exists in the North American population. However, one or more additional genes may yet be found that explain some proportion of hereditary breast cancer.

Paternal transmission of congenital myotonic dystrophy

The congenital form of myotonic dystrophy is reported to be almost exclusively, if not exclusively, maternally transmitted. We present a case of congenital myotonic dystrophy which was inherited from a mildly affected father. This family illustrates that the congenital form of myotonic dystrophy can occur without intrauterine or other maternal factors related to the disease. The possibility of paternal transmission of the congenital form of myotonic dystrophy could be considered when counselling myotonic dystrophy patients and their families.

Non-radioactive detection of the most common mutations in the cystic fibrosis transmembrane conductance regulator gene by multiplex allele-specific polymerase chain reaction

A rapid, simple, nonradioactive method for detection of four common mutations causing cystic fibrosis (CF) has been developed combining multiplexing with allele-specific polymerase chain reaction amplification. This approach (MASPCR) provides an easy assay for direct genotyping of normal and mutant CF alleles in homozygotes and heterozygotes. The strategy involves multiplex PCR of exons 10, 11, and 21 within the cystic fibrosis transmembrane conductance regulator (CFTR) gene in a single reaction containing three common oligoprimers and either the four normal or four mutant oligos corresponding to the delta F508, G551D, G542X, and N1303K mutations. Primers are chosen so that the size of the four PCR products differ, thereby facilitating detection on agarose gels following amplification in the same reaction. Patient samples are primed with either four normal or four mutant oligo mixtures, and PCR products run in parallel on gels to detect band presence or absence. This approach provides a simple and potentially automated method for cost-effective population screening.

Demonstration of passenger leukocytes in a case of Epstein-Barr virus posttransplant lymphoproliferative disorder using restriction fragment length polymorphism analysis

Lymphocytic populations of the posttransplant lymphoproliferative disorder in a completely matched renal allograft and a recipient's regional lymph node were examined, using restriction fragment length polymorphism analysis with probe YNH24 to the variable number tandem repeat D2S44. The donor's DNA was found in lymphocytes extracted from both the grafted kidney and the recipient's lymph node 26 days after engraftment. In both these organs, the results of in situ hybridization with a terminally biotin-labeled oligonucleotide probe to the Not I tandem repeat region of the Epstein-Barr virus (EBV) genome, as well as those of Southern blot hybridization to the EBV nuclear antigen region of the EBV genome, were positive. These findings confirmed the presence of the donor's lymphocytes ("passenger leukocytes") in the host nodal tissue in human renal transplantation and implicated EBV as playing a role in the development of posttransplant lymphoproliferative disorder. It is speculated that the EBV proliferative stimulus contributed to the recipient and the donor lymphocyte expansions. Alternatively, the proliferation of both lymphocyte populations could result from a mutual stimulation by minor histocompatibility or other antigens.

G to A polymorphism in the second exon of the BCL2 gene

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Molecular resemblance of an AIDS-associated lymphoma and endemic Burkitt lymphomas: implications for their pathogenesis

Non-Hodgkin lymphoma is a common feature of AIDS. Approximately 30-40% of these tumors exhibit clinical features suggestive of endemic Burkitt lymphoma: they are aggressive malignancies that occur in association with Epstein-Barr virus infection, they arise in the setting of immunosuppression, and they carry t(8;14) translocations without detectable rearrangement of the MYC oncogene. To understand the molecular basis of these parallels, we analyzed a case of Epstein-Barr-positive AIDS-associated undifferentiated lymphoma. Southern blots show that the tumor exhibits immunoglobulin joining segment rearrangement but no rearrangement of the MYC oncogene. Cloning of the rearranged joining segment allowed the isolation of recombinant clones encompassing the translocation breakpoint, and sequencing of the translocation junction disclosed that the breakpoint is situated 7 base pairs from the chromosome 14 site involved in a previously described endemic Burkitt lymphoma translocation. Furthermore, the breakpoint is situated far from MYC on chromosome 8, a constant finding in endemic Burkitt lymphomas. That the molecular architecture of the translocation in this case is strikingly similar to previously analyzed translocations from endemic Burkitt lymphomas strongly suggests that common molecular mechanisms must be operative in the pathogenesis of these tumors.

Interleukin-1 costimulatory activity on the interleukin-2 promoter via AP-1

Interleukin-1 (IL-1) is a major regulator of inflammation and immunity. IL-1 induces T lymphocyte growth by acting as a second signal (together with antigen) in enhancing the production of interleukin-2 (IL-2). An IL-1-responsive element in the promoter region of the human IL-2 gene was similar to the binding site for the transcription factor AP-1. IL-1 enhanced expression of c-jun messenger RNA, whereas the antigenic signal enhanced messenger RNA expression of c-fos. Thus, the two components of the AP-1 factor are independently regulated and the AP-1 factor may serve as a nuclear mediator for the many actions of IL-1 on cells.

Method for reducing the rate of light emission from chemiluminescent and bioluminescent reactions using frozen reagents

Frozen assay reagents have been used to reduce the rate of light emission from the rapid chemiluminescent acridinium ester and the bioluminescent firefly luciferase reactions. Melting of the assay reagent delays the initiation of the light emission, thus eliminating the need to initiate these rapid reactions by injection of the assay reagents in front of the photodetector.