Analysis of the CDR3 length repertoire and the diversity of T cell receptor α and ß chains in swine CD4+ and CD8+ T lymphocytes.

The T cell receptor (TCR) is a complex heterodimer that recognizes fragments of antigens as peptides and binds to major histocompatibility complex molecules. The TCR α and ß chains possess three hypervariable regions termed complementarity determining regions (CDR1, 2 and 3). CDR3 is responsible for recognizing processed antigen peptides. Immunoscope spectratyping is a simple technique for analyzing CDR3 polymorphisms and sequence length diversity, in order to investigate T cell function and the pattern of TCR utilization. The present study employed this technique to analyze CDR3 polymorphisms and the sequence length diversity of TCR α and ß chains in porcine CD4+ and CD8+ T cells. Polymerase chain reaction products of 19 TCR α variable regions (AV) and 20 TCR ß variable regions (BV) gene families obtained from the CD4+ and CD8+ T cells revealed a clear band following separation by 1.5% agarose gel electrophoresis, and each family exhibited >8 bands following separation by 6% sequencing gel electrophoresis. CDR3 spectratyping of all identified TCR AV and BV gene families in the sorted CD4+ and CD8+ T cells by GeneScan, demonstrated a standard Gaussian distribution with >8 peaks. CDR3 in CD4+ and CD8+ T cells demonstrated different expression patterns. The majority of CDR3 recombined in frame and the results revealed that there were 10 and 14 amino acid discrepancies between the longest and shortest CDR3 lengths in specific TCR AV and TCR BV gene families, respectively. The results demonstrated that CDR3 polymorphism and length diversity demonstrated different expression and utilization patterns in CD4+ and CD8+ T cells. These results may facilitate future research investigating the porcine TCR CDR3 gene repertoire as well as the functional complexity and specificity of the TCR molecule.

αß T-cell receptor bias in disease and therapy (Review).

The diversity and specificity of T cell receptors (TCR), the characteristics of T-cell surface marker, are central to the adaptive immunity. TCR variability is required for successful immunization coverage because this structural foundation is indispensable for the valid identification of short antigen peptides (derived from degraded antigens) that are presented by major histocompatibility molecules on the surfaces of antigen-presenting cells. Despite the vast T-cell repertoire, biased αß TCR has become a common theme in immunology. To date, numerous examples of TCR bias have been observed in various diseases. Immunotherapy strategies that are based on αß T cell responses are also emerged as a prominent component of clinical treatment. In the present review, we briefly summarize the current knowledge regarding basic structural information and the molecular mechanisms underlying TCR diversity. Moreover, we outline the role of TCR repertoire bias in some diseases, and its application for therapeutic interventions, as these play significant roles in disease progression, even with patients with a good prognosis.

Infection of mouse bone marrow-derived immature dendritic cells with classical swine fever virus C-strain promotes cells maturation and lymphocyte proliferation.

In this study, the interactions of classical swine fever virus (CSFV) C-strain and the virulent GSLZ strain with mouse bone marrow-derived immature dendritic cells (BM-imDCs) were investigated for the first time. Both the C-strain and the virulent GSLZ strain could effectively infect and replicate in mouse BM-imDCs. C-strain-infected BM-imDCs showed a greatly enhanced degree of maturation, and could effectively promote the expansion and proliferation of allogeneic naive T cells. The C-strain induced a stronger Th1 response. Infection with the virulent GSLZ strain had no obvious influence on cell maturation or lymphocyte proliferation, and failed to induce any obvious immune response. The results of this study provided initial information for research of the immunologic mechanisms of CSFV using mouse DCs as the model cells.

[Modulation of the host toll-like receptor signaling pathways by virus infection].

Toll-like receptors (TLRs) are germline-encoded pattern recognition receptors (PRRs) that play a central role in host cell recognition and responses to virus infection, leading to the production of interferons (IFNs) and proinflammatory cytokines. In parallel, in order to establish an infection, viruses have to develop exclusively strategies to interfere with TLRs signaling, particularly some important adaptors activation such as MyD88, NF-kappaB, TRIF and IRFs, and suppress or escape host's antiviral immune response. In this paper, we review the latest findings on the various strategies used by viruses to modulate TLRs-mediated innate immune response, with special emphasis on immune evasion mechanism of VACV, HCV and HIV. By highlighting recent progress in these areas, we hope to convey a greater understanding of how viruses hamper TLRs signaling and how to overcome viral infection.

[Construction, expression and immunogenicity of eukaryotic vectors based on goat pox virus P32 gene].

The full-length P32 gene and the truncated P32 gene (MP-32) were amplified from the recombinant plasmid pMD-P32 by polymerase chain reaction (PCR) and cloned into pcDNA3. 1(+) and pcDNA3.1-CpG respectively. The recombinant plasmids (pcDNA3.1-P32, pcDNA3.1-CpG-P32 and pcDNA3. 1-CpG-MP32) were transfected into BHK-21 cells by using lipofectin. The expressed P32 protein was confirmed by indirect immunofluorescence assay (IFA). The BALB/c mice were immunized with these recombinant plasmids by intramuscular injection. The specific antibodies aginst CPV were detected by ELISA kit weekly. The murine splenic T lymphocyte subgroups CD4+ and CD8+ were detected by flow cytometry. Results showed that the P32 protein was expressed successfully in vitro. After 2 weeks post im munization, the specific IgG antibodies against CPV were detected in the vaccinated mice. The percentage of CD4+ /CD8+ T cells was significantly higher than that of the control. In conclusion, these constructed eukaryotic vectors could induce humoral and celluar immune responses in mice.