Hepatitis B virus (HBV)-derived DRB1*0101-restricted CD4 T-cell epitopes help in the development of HBV-specific CD8+ T cells in vivo.

We previously identified two HLA-DRB1*0101-restricted epitopes in hepatitis B virus (HBV) X protein (HBx) and in HBV envelope proteins (preS2). To evaluated their help in the development of CD8+ T-cell responses, mice transgenic for human class I and class II HLA molecules were immunized with HBV-T helper constructs. The preS2 epitope favored a well-balanced response with CD4+ and CD8+ T cells producing IFN-gamma, IL-2 and TNF-alpha.

Impact of hepatitis B virus basic core promoter mutations on T cell response to an immunodominant HBx-derived epitope.

Unlabelled: The hepatitis B X (HBx) protein is a crucial component in HBV infection in vivo and has been implicated in HCC. In this study, we aimed to detect and characterize peripheral HBx-specific T cells in chronically infected patients at the inactive carrier state of the disease. HBx-specific IFN-gamma-secreting T cells were found in 36 of 52 patients (69%), and 78% (28/36) of responding patients had T cells targeting epitopes in the carboxy-terminal part of HBx.

In vivo hierarchy of immunodominant and subdominant HLA-A*0201-restricted T-cell epitopes of HBx antigen of hepatitis B virus.

A polyepitopic CD8+ T-cell response is critical for the control of hepatitis B virus (HBV) infection. The HBV X protein (HBx) is a multifunctional protein that is important for the viral life cycle and for host-virus interactions. The aim of this study was to analyze the immunogenicity and dominance of various HLA-A*0201-restricted HBx-derived epitopes.

Human serum antibodies against shared antigens of different stages of Trichinella spiralis: relevance of glycan and protein epitopes.

Taking into account that antibodies against the surface antigens of newborn larvae (anti-NBL Abs) present in sera from individuals with chronic trichinellosis recognize antigenic determinants of the excretory-secretory muscle larva products (ML-ESP), and that these products are mainly glycoproteins, the aim of this work was to assess the frequency of anti-NBL Abs in sera from individuals with acute and chronic trichinellosis, to analyse the relevance of glycan and protein epitopes of the ML-ESP in the cross-reactivity phenomenon, and its correlation with the host's serum response towards these products. Anti-NBL surface Abs were determined in sera by indirect immunofluorescence. The degree of recognition by serum and purified anti-NBL Abs was evaluated comparatively before and after chemical deglycosylation of ML-ESP by immunoelectrotransfer blot assay.

Diagnosis of human trichinellosis: pitfalls in the use of a unique immunoserological technique.

Serum samples belonging to three outbreaks in Argentina (47 patients) taken at different times post-ingestion were analysed employing IIF and ELISA simultaneously. Results show that: a) the number of patients diagnosed by a unique technique, especially by ELISA (31 patients), was lower than the one obtained by the simultaneous use of both assays (38 patients); b) four patients out of the seven diagnosed by a unique technique were negative by the other assay over the period of time evaluated. Therefore, it can be concluded that the use of a sole immunoserological technique can not only lead to the delay in the detection but also to the misdiagnosis of this parasitic infection.

Immunoelectrotransfer blot assay in acute and chronic human trichinellosis.

An immunoelectrotransfer blot assay (IETB) using excretory secretory products of muscle larvae of Trichinella spiralis (ML-ESP) and the avidin biotin system was developed in order to characterize reactivity against ML-ESP in sera from patients with acute and chronic trichinellosis. A complete pattern of up to 13 bands was developed by sera from individuals with trichinellosis where doublets, triplets, or single bands were shown to have molecular weights of roughly 66, 55, 45, 36, 29, 24, and 14 kDa. The bands at approximately 55, 36, 29, and 14 kDa proved specific for T.

Cytotoxicity-blocking antibodies in human chronic trichinellosis.

Antisurface newborn larva (NBL) antibodies (Abs) were found in sera from individuals chronically infected with Trichinella spiralis. These Abs were incapable of inducing NBL death by activation of normal human leukocytes of peripheral blood as determined by in vitro assays of antibody-dependent cell cytotoxicity (ADCC). Besides, such sera blocked the cytotoxic reaction mediated by Abs produced a few weeks after infection.

Evaluation of an enzymatic immunohistochemical technique in human trichinellosis.

A comparative study was undertaken between an enzymatic immunohistochemical technique (EIT) developed for the diagnosis of human trichinellosis and the indirect immunofluorescence test (IIF), analysing sera from outbreaks of human trichinellosis in Argentina. The EIT was developed using a biotinylated anti-human gammaglobulin and a preformed macromolecular complex of avidin and biotinylated peroxidase. In both tests, the antigen used consisted of infected rat tissue sections containing muscle larval cysts of Trichinella spiralis.

Diagnosis of porcine trichinellosis: parasitological and immunoserological tests in pigs from endemic areas of Argentina.

In order to compare the reliability of serological and parasitological techniques for the diagnosis of porcine trichinellosis from endemic areas in Argentina, 116 pigs were studied: 61 animals from two separate outbreaks and 55 from a small abattoir. Direct diagnostic techniques included trichinoscopy and the artificial digestion method. Indirect diagnostic tests used in this study were the enzyme-linked immunosorbent assay (ELISA), employing the excretory-secretory products of muscle larvae (ML) as antigen, and the indirect immunofluorescence assay using as antigen ML in suspension (IIF-susp), cryostat sections of infected rat muscle or of free ML (IIF-slide).