B淋巴细胞膜表面IgM在抗原提呈中的作用

ROLE OF B CELL SURFACE IgM IN ANTIGEN PRESENTATION

用T细胞增殖试验和IL-2活性检测法探讨B细胞膜表面IgM在抗原提呈中的作用,结果表明,B细胞与羊抗鼠IgM抗体在4℃作用1h后,再与破伤风类毒素抗原作用12h,B细胞抗原提是作用消失,而B细胞先与破伤风类毒素抗原作用12h后,再与抗鼠IgM抗体作用1h,则B细胞抗原提呈作用不受影响,提示B细胞膜表面IgM能摄取抗原,在抗原提呈中起关键性作用。

Previous studies showed that bothresting and lipopolysaccharide activated Bcells were very effective accessory cells andantigen presenting cells in T cell respondingto mitogens and antigens. This paper dis-cusses the role of B cell surface IgM inantigen presentation.Splenic B cells obtain-ed from C_(57)BL/6 mouse were depleted ofmacrophages, dendritic cells and T cells.The purified B cells were prepulsed withsheep anti-mouse IgM antibody (SaM) at4℃ for 60 min or with tetanus toxoidantigen (TT-Ag) at 37℃ for 12 h beforepulsing with TT-Ag or SaM. Then B cells(2×10~5/well) were used as antigen pres-enting cells without further addition of TT-Ag in TT-Ag primed T cell (2×10~5/well,obtained from TT-Ag immunized C_(57)BL/6mouse lymph node) proliferation. Theresults showed that antigen presentation ofB cells prepulsed with SaM before pulsingwith TT-Ag was blocked. But if B cellswere preincubated with TT-Ag beforepulsing with SaM, antigen presentationof B cells was not blocked by SaM. Theseresults have suggested that B cell surfaceIgM can take up antigen and can presentthe antigen to antigen specific T cells. Ithas also been revealed that B cell surfaceIgM by taking up antigen plays an impor-tant role in antigen presentation. Also,the biological significance of the role on Bcell surface IgM in antigen presentationis discussed.