Cluster of differentiation antigens: essential roles in the identification of teleost fish T lymphocytes.

Cluster of differentiation (CD) antigens are cell surface molecules expressed on leukocytes and other cells associated with the immune system. Antibodies that react with CD antigens are known to be one of the most essential tools for identifying leukocyte subpopulations. T lymphocytes, as an important population of leukocytes, play essential roles in the adaptive immune system. Many of the CD antigens expressed on T lymphocytes are used as surface markers for T lymphocyte classification, including CD3, CD4 and CD8 molecules. In this review, we summarize the recent advances in the identification of CD molecules on T lymphocytes in teleosts, with emphasis on the functions of CD markers in the classification of T lymphocyte subsets. We notice that genes encoding CD3, co-receptors CD4 and CD8 have been cloned in several fish species and antibodies have been developed to study protein expression in morphological and functional contexts. T lymphocytes can be divided into CD4+ and CD8+ cells discriminated by the expression of CD4 and CD8 molecules in teleost, which are functionally similar to mammalian helper T cells (Th) and cytotoxic T cells (Tc), respectively. Further studies are still needed on the particular characteristics of teleost T cell repertoires and adaptive responses, and results will facilitate the health management and development of vaccines for fish.

Kinetics of T lymphocyte subsets and B lymphocytes in response to immunostimulants in flounder (Paralichthys olivaceus): implications for CD4+ T lymphocyte differentiation.

CD4+ T lymphocytes play crucial roles in the adaptive immune system. CD4, as the most effective marker to delineate the T-helper subsets, was identified in many fish species. Two CD4 homologs, CD4-1 and CD4-2, have been reported in flounder (Paralichthys olivaceus). In this study, monoclonal antibodies (mAbs) against CD4-1 and CD4-2 of flounder were produced, CD4+ T lymphocytes were isolated and identified, and the variations in CD4+ and CD8+ T lymphocytes and IgM+ B lymphocytes after Poly I:C, PMA or ß-glucan stimulation were investigated. Then, the expression of transcription factors and cytokines in sorted CD4+ T lymphocytes was analyzed. The results showed that the mAbs were specific to flounder CD4-1+ and CD4-2+ T cells. CD4-1+ and CD4-2+ cells responded to all three stimulants, while CD8+ T lymphocytes only give a strong response to Poly I:C, and the percentages of IgM+ B lymphocytes showed a tendency to increase. After stimulation, the expression of transcription factors and cytokines of Th1, Th2 and Th17 cells varied in CD4+ T cells. These results will provide crucial foundations for the differentiation and function of teleost CD4+ T lymphocytes.

[Relationship between intrauterine infection and the gene polymorphism of DC-SIGN/DC-SIGNR in the pregnant women of HBV positive].

OBJECTIVE: To investigate the influence of the individual genotype differences of DC-SIGN and DC-SIGNR on the mother-to-neonate intrauterine infection of HBV. METHODS: The genotypes of the gene DC-SIGN and DC-SIGNR in the pregnant women with HBV positive were detected by PCR and agarose gel electrophoresis. The significant difference of gene diversity of DC-SIGN and DC-SIGNR was analyzed by chi-square test. RESULTS: (1) All of 29 cases in intrauterine infection group were 7/7 DC-SIGN genotype. In the non-intrauterine infection group, 7/5 genotype were observed in 2 of 54 cases, and the other 52 cases were 7/7 genotype. The two groups was no significant difference (P = 0.54). (2) 29 cases of intrauterine infection group was observed 4 genotypes of DC-SIGNR such as 7/7, 7/5, 9/7 and 6/5, the genotype frequencies were 0.3793, 0.3448, 0.2414 and 0.0345 respectively. 54 cases of non-intrauterine infection group was found 6 genotypes such as 7/7, 7/5, 9/5, 9/7, 7/6 and 6/5, genotype frequencies were 0.5186, 0.1481, 0.0926, 0.1852, 0.0370 and 0.0185 respectively. The distribution of 7/5 genotype in the intrauterine infection group (29 cases) and the non-intrauterine infection group (54 cases) was statistically significant (P = 0.038) , and no significant difference was found in other genotypes between the two groups (P > 0.05). CONCLUSION: The gene DC-SIGN showed relatively little variation in the pregnant women infected with HBV. On the countrary, there were multiple genotypes of the gene DC-SIGNR in these women, and the genotype "7/5" of DC-SIGNR might be one of the susceptibility genes associated with intrauterine infection.