TCR V alpha- and V beta-gene segment use in T-cell subcultures derived from a type-III bare lymphocyte syndrome patient deficient in MHC class-II expression.

Previously, we and others have shown that MHC class-II deficient humans have greatly reduced numbers of CD4+CD8- peripheral T cells. These type-III Bare Lymphocyte Syndrome patients lack MHC class-II and have an impaired MHC class-I antigen expression. In this study, we analyzed the impact of the MHC class-II deficient environment on the TCR V-gene segment usage in this reduced CD4+CD8- T-cell subset. For these studies, we employed TcR V-region-specific monoclonal antibodies (mAbs) and a semiquantitative PCR technique with V alpha and V beta amplimers, specific for each of the most known V alpha- and V beta-gene region families. The results of our studies demonstrate that some of the V alpha-gene segments are used less frequent in the CD4+CD8- T-cell subset of the patient, whereas the majority of the TCR V alpha- and V beta-gene segments investigated were used with similar frequencies in both subsets in the type-III Bare Lymphocyte Syndrome patient compared to healthy control family members. Interestingly, the frequency of TcR V alpha 12 transcripts was greatly diminished in the patient, both in the CD4+CD8- as well as in the CD4-CD8+ compartment, whereas this gene segment could easily be detected in the healthy family controls. On the basis of the results obtained in this study, it is concluded that within the reduced CD4+CD8- T-cell subset of this patient, most of the TCR V-gene segments tested for are employed. However, a skewing in the usage frequency of some of the V alpha-gene segments toward the CD4-CD8+ T-cell subset was noticeable in the MHC class-II deficient patient that differed from those observed in the healthy family controls.

Phenotypic characteristics of human type II alveolar epithelial cells suitable for antigen presentation to T lymphocytes.

Type II alveolar epithelial cells (AECII) are well known for their role in the innate immune system. More recently, it was proposed that they could play a role in the antigen presentation to T lymphocytes but contradictory results have been published both concerning their surface expressed molecules and the T lymphocyte responses in mixed lymphocyte cultures. The use of either AECII cell line or fresh cells could explain the observed discrepancies. Thus, this study aimed at defining the most relevant model of accessory antigen presenting cells by carefully comparing the two models for their expression of surface molecules necessary for efficient antigen presentation.

Expression, purification and X-ray crystallographic analysis of the Helicobacter pylori blood group antigen-binding adhesin BabA

Helicobacter pylori is a human pathogen that colonizes about 50% of the world's population, causing chronic gastritis, duodenal ulcers and even gastric cancer. A steady emergence of multiple antibiotic resistant strains poses an important public health threat and there is an urgent requirement for alternative therapeutics. The blood group antigen-binding adhesin BabA mediates the intimate attachment to the host mucosa and forms a major candidate for novel vaccine and drug development. Here, the recombinant expression and crystallization of a soluble BabA truncation (BabA^25-460) corresponding to the predicted extracellular adhesin domain of the protein are reported. X-ray diffraction data for nanobody-stabilized BabA^25-460 were collected to 2.25Å resolution from a crystal that belonged to space group P21, with unit-cell parameters a = 50.96, b = 131.41, c = 123.40Å, α = 90.0, β = 94.8, γ = 90.0°, and which was predicted to contain two BabA^25-460-nanobody complexes per asymmetric unit.

The mycobacterial heparin-binding hemagglutinin, virulence factor and antigen useful for diagnostics and vaccine development.

info:eu-repo/semantics/published

The heparin-binding haemagglutinin, a latency antigen useful for vaccine development

info:eu-repo/semantics/nonPublished

High number of antigen binding cells in unimmunized mice and possible occurrence of multispecific lymphocytes

A high frequency of Tobacco Mosaic virus (TMV) binding cells was found in spleen cells from unimmunized mice (about 3 to 4%). TMV binding is strongly inhibited by previous incubation with anti immunoglobulin antisera. After stripping of membrane receptors, a full recovery for antigen binding capacity can be observed after 24 hr culture. Experiments are presented to exclude artefactual fluorescent cells: interaction of TMV with some non immunoglobulin membrane components; interaction of fluorescent anti TMV antibody with the Fc receptor of B cells; the binding of TMV to cytophilic immunoglobulins. The occurrence of lymphocytes able to bind several non crossreactive antigens is suggested by three lines of evidence: the high number of antigen binding cells in unimmunized mice, presence of surface immunoglobulins on some TMV binding cells after complete capping of TMV receptors and the direct demonstration of lymphocytes binding TMV and hemocyanin at different membrane sites.