Safety and immunogenicity of a Shigella flexneri 2a Invaplex 50 intranasal vaccine in adult volunteers

Shigellosis is a leading cause of diarrhea worldwide prompting vaccine development. The Shigella flexneri Invaplex 50 is a macromolecular complex containing IpaB, IpaC, and LPS, formulated from an aqueous extract of virulent Shigella delivered via nasal administration. Preclinical vaccine testing demonstrated safety, immunogenicity and efficacy. An open-label dose-escalating phase 1 study evaluated a 3-dose (2-week intervals) regimen via nasal pipette delivery. Thirty-two subjects were enrolled into one of four vaccine dose groups (10, 50, 240, or 480 microg). The vaccine was well tolerated with minor short-lived nasal symptoms without evidence of dose effect. Antibody-secreting cell (ASC) responses were elicited at doses > or =50 microg with the highest IgG ASC, Invaplex 50 (100%) and S. flexneri 2a LPS (71%), as well as, serologic responses (43%) occurring with the 240 microg dose. Fecal IgA responses, Invaplex 50 (38.5%) and LPS (30.8%), were observed at doses > or =240 microg. The Invaplex 50 nasal vaccine was safe with encouraging mucosal immune responses. Follow-on studies will optimize dose, delivery mechanism and assess efficacy in a S. flexneri 2a challenge study.

TSH receptor - autoantibody interactions

TSH receptor (TSHR) autoantibodies (TRAbs)activate the TSHR cyclic AMP cascade (stimulating TRAbs) or act as TSHR antagonist (blocking TRAbs), and both types inhibit TSH binding to the TSHR. Isolation of human monoclonal TSHR autoantibodies (stimulating M22 and blocking 5C9) has been a key milestone in studies of the TSHR and TSHR autoimmunity. Comparison of M22 and TSH interactions with the TSHR at the atomic level reveal that M22 heavy and light chains mimic TSH alpha and beta chains, respectively, in the way they bind to the receptor, but the evolutionary forces which have caused this close molecular mimicry are as yet completely unknown. More recently two more human monoclonal antibodies to the TSHR (K1-18 with stimulating and K1-70 with blocking activities) have been isolated from a single blood sample collected from a patient with hypothyroidism who previously presented with hyperthyroidism. K1-18 and K1-70 were derived from different lymphocytes as shown by V region genes analysis. This provides, for the first time, clear proof that a patient can produce both blocking and stimulating TRAbs at the same time. Although it has been postulated that stimulating and blocking TRAbs bind to different regions on the TSHR, our studies showed that antibodies of both types bind well to the TSHR containing only N-terminal amino acids 22-260. Whether TRAbs make contact with other parts of the TSHR in order to produce their biological effects (stimulation or blocking) remains to be elucidated.

Thyroid stimulating autoantibody M22 mimics TSH binding to the TSH receptor leucine rich domain: a comparative structural study of protein-protein interactions

The TSH receptor (TSHR) ligands M22 (a thyroid stimulating human monoclonal antibody) and TSH, bind to the concave surface of the leucine rich repeats domain (LRD) of the TSHR and here, we show that M22 mimics closely the binding of TSH. We compared interactions produced by M22 with the TSHR in the M22-TSHR crystal structure (2.55 A resolution) and produced by TSH with the TSHR in a TSH-TSHR comparative model. The crystal structure of the TSHR and a comparative model of TSH based on the crystal structure of FSH were used as components to build the TSH-TSHR model. This model was built based on the FSH-FSH receptor structure (2.9 A) and then the structure of the TSHR in the model was replaced by the TSHR crystal structure. The analysis shows that M22 light chain mimics the TSHbeta chain in its interaction with TSHR LRD, while M22 heavy chain mimics the interactions of the TSHalpha chain. The M22-TSHR complex contains a greater number of hydrogen bonds and salt bridges and fewer hydrophobic interactions than the TSH-TSHR complex, consistent with a higher M22 binding affinity. Furthermore, the surface area formed by TSHR residues N208, Q235, R255, and N256 has been identified as a candidate target region for small molecules which might selectively block binding of autoantibodies to the TSHR.

FSH and TSH binding to their respective receptors: similarities, differences and implication for glycoprotein hormone specificity

The crystal structures of the leucine-rich repeat domain (LRD) of the FSH receptor (FSHR) in complex with FSH and the TSH receptor (TSHR) LRD in complex with the thyroid-stimulating autoantibody (M22) provide opportunities to assess the molecular basis of the specificity of glycoprotein hormone-receptor binding. A comparative model of the TSH-TSHR complex was built using the two solved crystal structures and verified using studies on receptor affinity and activation. Analysis of the FSH-FSHR and TSH-TSHR complexes allowed identification of receptor residues that may be important in hormone-binding specificity. These residues are in leucine-rich repeats at the two ends of the FSHR and the TSHR LRD structures but not in their central repeats. Interactions in the interfaces are consistent with a higher FSH-binding affinity for the FSHR compared with the binding affinity of TSH for the TSHR. The higher binding affinity of porcine (p)TSH and bovine (b)TSH for human (h)TSHR compared with hTSH appears not to be dependent on interactions with the TSHR LRD as none of the residues that differ among hTSH, pTSH or bTSH interact with the LRD. This suggests that TSHs are likely to interact with other parts of the receptors in addition to the LRD with these non-LRD interactions being responsible for affinity differences. Analysis of interactions in the FSH-FSHR and TSH-TSHR complexes suggests that the alpha-chains of both hormones tend to be involved in the receptor activation process while the beta-chains are more involved in defining binding specificity.

Unravelling the genome: a review of molecular genetic research in schizophrenia

BACKGROUND

Schizophrenia is a common and complex mental illness that affects approximately 1% of the population worldwide. Despite intensive research over the years, the aetiology and pathogenesis of schizophrenia is poorly understood. However, it has long been recognised that schizophrenia is highly familial suggesting a possible genetic aetiology.

AIM

To review recent molecular genetic research in schizophrenia.

METHODS

Medline and Embase search.

RESULTS

Over the past decade, with the completion of the Human Genome Project, molecular genetic research has now identified a number of genes that are very likely to predispose to schizophrenia.

CONCLUSION

This article discusses the methodologies that have been used to identify schizophrenia susceptibility genes and provides a review of recently identified genes thought to play a role in the pathogenesis of this illness.

A comparative analysis of angiogenesis between male and female breast cancers

21101

Background: Tumor angiogenesis and vascularization are essential for the growth and metastasis of tumors. VEGF-C expression and peritumoral lymphocyte density (PLD) are markers of angiogenesis. They have been correlated with poor prognosis in female breast cancer (FBC). The purpose of this study is to characterize VEGF-C expression and PLD in MBC and correlate with FBC specimens. Method: We reviewed records of patients diagnosed with MBC and FBC at the Cincinnati VAMC, from 1989 to 2006. Pathology slides were retrieved. We used VEGF-C (Host Rabbit, PAD: Z-CVC7) . Imunohistochemical stains of VEGF-C were given scores of 0 to 3+ based on nuclear stains. PLD was analyzed based on the number of lymphocyte cells surrounding the tumor; score of 0 to 3+. Slides were reviewed independently by two pathologists. Results: We found nine MBC cases and selected 9 FBC cases. Mean age was 72 in the male patients and 62 in the females. Stages of disease were distributed as follows in MBC versus FBC, 11% versus 22% stage 0, 23% versus 23% stage I, 44% versus 44% stage II, and 22% versus 11% stage IV. Ductal carcinoma was the predominant histology in 88% of FBC and 88% MBC. Other histological types included papillary (1 MBC) and lobular (1 FBC). Among the invasive MBC tumors , 75 % were ER+/PR +, 13% ER+/PR-, and 12% ER -/PR- , compared to 72 % ER+/PR+, 14% ER+/PR-, and 14% ER-/PR- in FBC. Eight out of the 9 MBC cases (89%) stained positive for VEGF-C expression, compared to one FBC case (11%). The 1 male breast intraductal carcinoma was positive for VEGF-C expression, compared to none of the two intraductal FBC. PLD was more intense in male than female tumors : score 0 or 1+: 44% in MBC versus 67% in FBC , score 2+: 22% in MBC Versus 22% in FBC, and score 3+: 22% in MBC versus 11% in FBC. VEGF-C expression did not seem to correlate with ER/PR status. The median survival for patients with MBC was 4.5 years and for patients with FBC 6.9 years. Conclusion: VEGF-C expression and PLD were more pronounced in MBC versus FBC. This finding may correlate with more aggressive behavior of breast tumor cells in male patients, more intense angiogenic reaction and lower median survival. Further studies are warranted to further elucidate the role of angiogenesis in male breast cancer and explore potential antiangiogenic therapeutic modalities.

No significant financial relationships to disclose.

Autologous bone marrow transplantation for children with AML in first remission

In Children's cancer group (CCG) 2891, newly diagnosed patients with AML were randomized between standard and intensive timing induction therapies. Patients in first remission who lacked an HLA matched family donor were randomized between an autologous bone marrow transplantation (ABMT) where marrow was purged with 4 hydroperoxycyclophosphamide and consolidation chemotherapy. One hundred and thirty seven patients received an ABMT. Myeloid and platelet engraftment occurred at a median of 44 and 42 days, respectively. Disease-free survival (DFS), relapse-free survival and overall survival at 8 years post induction were 47% (95% confidence interval (CI): 38-55), 50% (CI: 42-59) and 55% (CI: 46-63), respectively. Multivariate analysis of DFS showed WBC <50 000/microl and having received intensively timed induction therapy were associated with improved DFS. Recipients who received intensive timed induction therapy and whose WBC was less than 50 000/microl had a DFS at 8 years of 62% (CI: 49-73). Conversely, recipients who received intensive timed induction therapy patients whose WBC was > or =50 000/microl had a DFS of 33% (CI: 17-50), P=0.003. The results confirm previous studies that ABMT is effective post remission therapy for pediatric patients with AML in first remission.

Effects of a thyroid-stimulating human monoclonal autoantibody (M22) on functional activity of LH and FSH receptors

OBJECTIVE

The glycoprotein hormones luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyrotropin (TSH) show low-level cross-reactivity between their respective receptors (R). Patient serum autoantibodies to the thyrotropin receptor (TSHR) do not appear to cross-react with the luteinizing hormone receptor (LHR) or follicle-stimulating hormone receptor (FSHR), although the concentrations of autoantibody with which it is feasible to carry out experiments of this type are limited. Consequently, we have studied the effects of high doses of the thyroid-stimulating human monoclonal autoantibody (M22) on the LHR and FSHR.

DESIGN

Chinese Hamster ovary (CHO) cells stably expressing the TSHR, LHR, and FSHR and purified M22 IgG preparations were used in the study.

METHODS

CHO-TSHR, CHO-LHR, and CHO-FSHR cells were incubated with bovine TSH (0.1-25mU/mL), human recombinant chorionic gonadotropin (hCG; 0.5-10mU/mL) or human recombinant FSH (100-5000mU/mL) or with M22 IgG (0.001-5.0 microg/mL), and the extracellular cyclic AMP was measured by radioimmunoassay.

RESULTS

Cyclic AMP levels increased in a dose-dependent manner after incubation of CHO-TSHR cells with TSH or M22 IgG, and on a molar basis the effects of TSH and M22 were similar. Cyclic AMP stimulation was not detectable in CHO-LHR and CHO-FSHR cells after incubation with M22 IgG, whereas incubation with hCG or FSH, respectively, caused dose-dependent cyclic AMP stimulation. On a molar basis, concentrations of M22 IgG approximately 100x those of FSH causing clear stimulation were ineffective with CHO-FSHR cells. Similarly, molar concentration of M22 IgG 20,000x those of hCG causing clear stimulation had no effect on CHO-LHR cells.

CONCLUSIONS

This study shows that at relatively high concentrations, M22 IgG is unable to stimulate cyclic AMP levels in CHO-LHR or CHO-FSHR cells, suggesting that TSHR autoantibodies have greater specificity for the TSHR than TSH itself.

Low-dose cyclophosphamide conditioning for haematopoietic cell transplantation from HLA-matched related donors in patients with Fanconi anaemia

Allogeneic haematopoietic cell transplantation (HCT) is effective therapy for Fanconi anaemia (FA). FA patients do not tolerate conditioning with 200 mg/kg of cyclophosphamide (Cy), typically used in aplastic anaemia. We previously published results of studies in which Cy doses were gradually reduced from 200 to 100 mg/kg. Here we update results of the initial studies and report data on 30 new patients conditioned with Cy either at 80 mg/kg (n = 7) or at 60 mg/kg (n = 23), given over 4 days before HCT from human leucocyte antigen-matched related donors. Methotrexate and cyclosporine were given for graft-versus-host disease (GVHD) prophylaxis. All seven patients given Cy at 80 mg/kg and 21 of 23 given Cy at 60 mg/kg had sustained engraftment, while two patients, both with clonal cytogenetics abnormalities, experienced graft failure. Grades 2-3 acute GVHD rates were 57% and 14% for patients given the higher and lower Cy doses, respectively (P = 0.001). Four patients given Cy at 80 mg/kg and 22 given Cy at 60 mg/kg were alive at a median of 47 (44-58) months and 16 (3-52) months, respectively. Cy at 60 mg/kg has acceptable toxicities, low rates of GVHD, and is sufficient for engraftment of related grafts in most FA patients.

Reduction of exit-site infections of tunnelled intravascular catheters among neutropenic patients by sustained-release chlorhexidine dressings: results from a prospective randomized controlled trial

Exit-site and tunnel infections of tunnelled central intravascular catheters are a frequent source of morbidity among neutropenic patients and may necessitate catheter removal. They require antimicrobial therapy that increases healthcare costs and is associated with adverse drug reactions. A prospective randomized clinical trial was conducted among adult patients undergoing chemotherapy in a haematology unit. Tunnelled intravascular catheters were randomized to receive the control of a standard dressing regimen as recommended by the British Committee for Standards in Haematology, or to receive the intervention of a sustained-release chlorhexidine dressing. Follow-up data were available in 112 of 114 tunnelled intravascular catheters which were randomized. Exit-site or combined exit-site/tunnel infections occurred in 23 (43%) of 54 catheters in the control group, and five (9%) of 58 catheters in the intervention group [odds ratio (OR) for intervention group compared with control group =0.13, 95% confidence intervals (CI) 0.04-0.37, P<0.001]. More tunnelled intravascular catheters were prematurely removed from the control group than the intervention group for documented infections [20/54 (37%) vs 6/58 (10%), OR=0.20, 95%CI 0.53-0.07]. However, there was no difference in the numbers of tunnelled intravascular catheters removed for all proven and suspected intravascular catheter-related infections [21/54 (39%) vs 19/58 (33%)], or in the time to removal of catheters for any reason other than death or end of treatment for underlying disease. Thus chlorhexidine dressings reduced the incidence of exit-site/tunnel infections of indwelling tunnelled intravascular catheters without prolonging catheter survival in neutropenic patients, and could be considered as part of the routine management of indwelling tunnelled intravascular catheters among neutropenic patients.

Characteristics of a monoclonal antibody to the thyrotropin receptor that acts as a powerful thyroid-stimulating autoantibody antagonist

Analysis of nine mouse monoclonal antibodies (mAbs) to the thyrotropin receptor (TSHR) with TSH antagonist activity showed that only one of the mAbs (RSR B2) was an effective antagonist of the human thyroid stimulating autoantibody M22. Crystals of B2 Fab were analyzed by x-ray diffraction and a crystal structure at 3.3 A resolution was obtained. The surface charge and topography of the B2 antigen binding site were markedly different from those of the thyroid-stimulating mAb M22 and these differences might contribute to the different properties of the two mAbs. B2 (but not other mouse TSHR-specific mAbs) was also an effective antagonist of thyroid stimulating autoantibody activity in 14 of 14 different sera from patients with Graves' disease. 125I-labeled B2 bound to the TSHR with high affinity (2 x 10(10) L/mol) and patient serum TSHR autoantibodies inhibited labeled B2 binding to the receptor in a similar way to inhibition of labeled TSH binding (r = 0.75; n = 20). Furthermore, labeled B2 binding was inhibited by patient serum TSHR autoantibodies with TSH antagonist activity and also by mouse and human thyroid stimulating mAbs. Overall, mAb B2 is a powerful antagonist of thyroid stimulating autoantibodies (and TSH) thus resembling closely patient serum TSH antagonist TSHR autoantibodies. Furthermore, B2 might have potentially important in vivo applications when tissues containing the TSHR (including those in the orbit) need to be made unresponsive to stimulating autoantibodies.

Isolation and characterisation of a human monoclonal autoantibody to the islet cell autoantigen IA-2

A hybridoma secreting a human monoclonal autoantibody to the islet cell autoantigen IA-2 was prepared from peripheral lymphocytes of a patient with type 1 diabetes and Graves' disease using EBV infection followed by fusion with a mouse/human hybrid cell line. The monoclonal antibody (M13) is an IgG1/kappa and in an immunofluorescence test M13 at 1 microg/mL showed islet cell antibody reactivity equivalent to 40 JDF units. M13 IgG bound (35)S-labelled IA-2 (26% at 100 microg/mL) and (125)I-labelled IA-2 (34% at 100 microg/mL) in an immunoprecipitation assay and reacted well with IA-2 in western blotting analysis. Amino acids 777-808 in the PTP domain of IA-2 were found to be important for M13 binding in an analysis using modified (35)S-labelled IA-2 proteins. M13 V region genes were from VH1-3, D3-22, JH4b, VKI DPK8/Vd+ and JK3 genes and showed a high replacement/silent mutation ratio for both the heavy (11.0) and the light (6.0) chain genes. Mouse monoclonal antibodies (mMAbs) reactive with at least three different epitopes within IA-2 aa 604-686 corresponding to the juxtamembrane domain were also obtained. F(ab')(2) or Fab from the mMAbs inhibited serum IA-2 autoantibody binding to IA-2 in 20/22 diabetic sera whereas M13 F(ab')(2) caused inhibition in only 6/22 sera. M13 is representative of some patient serum IA-2 autoantibodies and as such provides a useful tool to study autoimmune responses to IA-2.

Postremission therapy for children with acute myeloid leukemia: the children's cancer group experience in the transplant era

We reviewed consolidation therapy results and analyzed postremission outcomes for 1464 children less than 21 years old at diagnosis in five consecutive Children's Cancer Group acute myeloid leukemia trials between 1979 and 1996. Children in remission were allocated to allogeneic bone marrow transplantation (BMT) (N=373) in first remission, if a matched family donor was available. Remaining children were assigned consolidation chemotherapy (N=688) or autologous purged BMT (N=217), or withdrew from study before assignment, or with unknown data (N=186). Overall and disease-free survival were superior for children assigned allogeneic transplants. High (>50,000/microl) diagnostic white blood cell (WBC) count was prognostic for inferior outcome, but French-American-British (FAB) subtypes were not. Inv(16) is a favorable karyotypic feature for children in first remission and t(8;21) is not. Allogeneic transplantation benefit was evident in most children, including those with high or low diagnostic WBC count, each FAB subtype, and t(8;21), but was not seen in children with inv(16). Therefore, these data suggest reserving matched related donor allogeneic transplantation for children with inv(16) for second remission, but not those with t(8;21).

Characteristics of a human monoclonal autoantibody to the thyrotropin receptor: sequence structure and function

The properties of a human monoclonal antibody to the thyrotropin receptor (TSHR) (M22) with the characteristics of patient sera thyroid stimulating autoantibodies is described. Similar concentrations (pmol/L) of M22 Fab and porcine TSH had similar stimulating effects on cyclic adenosine monophosphate (cAMP) production in TSHR-transfected Chinese hamster ovary cells whereas higher doses of intact M22 immunoglobulin G (IgG) were required to cause the same level of stimulation. Patient sera containing TSHR autoantibodies with TSH antagonist (blocking) activity inhibited M22 Fab and IgG stimulation in a similar way to their ability to block TSH stimulation. Thyroid-stimulating monoclonal antibodies (TSmAbs) produced in mice inhibited 125I-TSH binding and 125I-M22 Fab binding to the TSHR but the mouse TSmAbs were less effective inhibitors than M22. These competition studies emphasized the close relationship between the binding sites on the TSHR for TSH, TSHR autoantibodies with TSH agonist activity, and TSHR autoantibodies with TSH antagonist activity. Recombinant M22 Fab could be produced in Escherichia coli and the recombinant and hybridoma produced Fabs were similarly active in terms of inhibition of TSH binding and cAMP stimulation. The crystal structure of M22 Fab was determined to 1.65 A resolution and is that of a standard Fab although the hypervariable region of the heavy chain protrudes further from the framework than the hypervariable region of the light chain. The M22 antigen binding site is rich in aromatic residues and its surface is dominated by acidic patches on one side and basic patches on the other in agreement with an important role for charge-charge interactions in the TSHR-autoantibody interaction.

Viral clearance occurs very early during the natural resolution of hepatitis C virus infection in persons with haemophilia

We studied spontaneous hepatitis C virus (HCV) RNA clearance in 12 haemophilic patients. In their earliest anti-HCV positive samples, HCV RNA was undetectable in eight patients (66%), positive by polymerase chain reaction (PCR) but negative by branched-DNA (bDNA) in three others, and quantifiable by bDNA (4839 IU/mL) in only one patient. In contrast, in earliest anti-HCV positive samples from eight matched controls who had persistent viremia, HCV RNA was quantifiable by bDNA in seven (P = 0.0008) and at higher levels (range 4644-678 515 IU/mL; median 43 532 IU/mL). From initial HCV infection, HCV RNA cleared in 7 months or less in four patients and in 1-2 years in six others. HCV persisted for 5 years before clearance in the absence of repeated exposure in one patient. We conclude that HCV clearance usually but not always occurs within 1-2 years after infection and is more likely in those with lower than in those with higher early viral loads.

Human monoclonal thyroid stimulating autoantibody

A monoclonal autoantibody (MAb) with powerful thyroid stimulating activity has been produced from lymphocytes from a patient with Graves' disease. The autoantibody and its Fab fragment bind to the thyroid stimulating hormone (TSH) receptor (TSHR) with high affinity, inhibit labelled TSH binding to the receptor and stimulate cyclic AMP production in Chinese hamster ovary cells transfected with TSHR. TSHR autoantibodies with TSH agonist or antagonist activities from patients' serum samples are effective inhibitors of labelled monoclonal autoantibody binding to TSHR. Thus, the human monoclonal autoantibody has all the characteristics of serum TSHR autoantibodies. Its availability has important implications for new studies on the pathogenesis of Graves' disease.