Vaccines against gastroenteritis,current progress and challenges

ABSTRACT

Enteric viral and bacterial infections continue to be a leading cause of mortality and morbidity in young children in low-income and middle-income countries, the elderly, and immunocompromised individuals. Vaccines are considered an effective and practical preventive approach against the predominantly fecal-to-oral transmitted gastroenteritis particularly in the resource-limited countries or regions where implementation of sanitation systems and supply of safe drinking water are not quickly achievable. While vaccines are available for a few enteric pathogens including rotavirus and cholera, there are no vaccines licensed for many other enteric viral and bacterial pathogens. Challenges in enteric vaccine development include immunological heterogeneity among pathogen strains or isolates, a lack of animal challenge models to evaluate vaccine candidacy, undefined host immune correlates to protection, and a low protective efficacy among young children in endemic regions. In this article, we briefly updated the progress and challenges in vaccines and vaccine development for the leading enteric viral and bacterial pathogens including rotavirus, human calicivirus, Shigella, enterotoxigenic Escherichia coli (ETEC), cholera, nontyphoidal Salmonella, and Campylobacter, and introduced a novel epitope- and structure-based vaccinology platform known as MEFA (multiepitope fusion antigen) and the application of MEFA for developing broadly protective multivalent vaccines against heterogenous pathogens.     

Recombinant Lactococcus Expressing a Novel Variant of Infectious Bursal Disease Virus VP2 Protein Can Induce Unique Specific Neutralizing Antibodies in Chickens and Provide Complete Protection

Recent reports of infectious bursal disease virus (IBDV) infections in China, Japan, and North America have indicated the presence of variant, and the current conventional IBDV vaccine cannot completely protect against variant IBDV. In this study, we constructed recombinant Lactococcus lactis (r-L. lactis) expressing a novel variant of IBDV VP2 (avVP2) protein along with the Salmonella resistance to complement killing (RCK) protein, and Western blotting analysis confirmed that r-L. lactis successfully expressed avVP2-RCK fusion protein. We immunized chickens with this vaccine and subsequently challenged them with the very virulent IBDV (vvIBDV) and a novel variant wild IBDV (avIBDV) to evaluate the immune effect of the vaccine. The results show that the r-L. lactis-avVP2-RCK-immunized group exhibited a 100% protection rate when challenged with avIBDV and 100% survival rate to vvIBDV. Furthermore, this immunization resulted in the production of unique neutralizing antibodies that cannot be detected by conventional ELISA. These results indicate that r-L. lactis-avVP2-RCK is a promising candidate vaccine against IBDV infections, which can produce unique neutralizing antibodies that cannot be produced by other vaccines and protect against IBDV infection, especially against the variant strain.     

Genetic variants of immunoglobulin γ and κ chains influence humoral immunity to the cancer‐testis antigen XAGE‐1b (GAGED2a) in patients with non‐small cell lung cancer

GM (γ marker) allotypes, genetic variants of immunoglobulin γ chains, have been reported to be associated strongly with susceptibility to lung cancer, but the mechanism(s) underlying this association is not known. One mechanism could involve their contribution to humoral immunity to lung tumour‐associated antigens. In this study, we aimed to determine whether particular GM and KM (κ marker) allotypes were associated with antibody responsiveness to XAGE‐1b, a highly immunogenic lung tumour‐associated cancer‐testis antigen. Sera from 89 patients with non‐small cell lung cancer (NSCLC) were allotyped for eight GM and two KM determinants and characterized for antibodies to a synthetic XAGE‐1b protein. The distribution of various GM phenotypes was significantly different between XAGE‐1b antibody‐positive and ‐negative patients (P = 0·023), as well as in the subgroup of XAGE‐1b antigen‐positive advanced NSCLC (P = 0·007). None of the patients with the GM 1,17 21 phenotype was positive for the XAGE‐1b antibody. In patients with antigen‐positive advanced disease, the prevalence of GM 1,2,17 21 was significantly higher in the antibody‐positive group than in those who lacked the XAGE‐1b antibody (P = 0·026). This phenotype also interacted with a particular KM phenotype: subjects with GM 1,2,17 21 and KM 3,3 phenotypes were almost four times (odds ratio = 3·8) as likely to be positive for the XAGE‐1b antibody as the subjects who lacked these phenotypes. This is the first report presenting evidence for the involvement of immunoglobulin allotypes in immunity to a cancer‐testis antigen, which has important implications for XAGE‐1b‐based immunotherapeutic interventions in lung adenocarcinoma.     

Serum tissue polypeptide-specific antigen is an independent predictor in breast cancer

Tissue polypeptide-specific antigen (TPS) is a tumor proliferative marker associated with cytokeratin 18. The aim of the study was to investigate the potential relationship between the preoperative serum TPS levels and the outcome in Chinese breast cancer patients. 975 consecutive female patients, affected by invasive breast cancer under investigation from January 2005 to December 2011, had their TPS levels measured with a one-step solid phase radiometric sandwich assay detecting the M3 epitope on cytokeratin 18 fragments. The cut-off value was 80 U/L. The average age diagnosed with breast cancer was 48, ranging from 23 to 71. About 19% (185) patients displayed an elevated preoperative TPS level (>80 U/L) associated with older age (>45), advanced cancer stage, larger tumor size (>2 cm), axillary lymph node metastasis, negative progesterone receptor status, and positive HER2 status. In addition, preoperative TPS levels were also significantly connected with recurrence (p < 0.05), particularly distant metastasis and visceral metastasis. The mean preoperative TPS level was 68.4 ± 116.43 U/L (range 0–1839 U/L). In multivariate analysis, high preoperative TPS level was recognized as an independent prognostic factor for disease-free survival (p < 0.001 and overall survival (p = 0.023). From these results we conclude that the serum preoperative TPS level may be a valuable and independent marker for breast cancer.     

T细胞在慢性乙型肝炎发病机制中的作用研究进展

慢性乙型肝炎已成为全球重要的公共卫生问题之一,获得性适应性免疫应答在慢性HBV感染最终结局的形成中起着核心作用,T细胞在适应性免疫应答中起关键作用。本文对T细胞在慢性乙型肝炎发病机制中作用的研究进展进行综述。