Roberts J L, Abe R, Shores E W, Singer A
Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
J Immunol. 1992 Sep 1;149(5):1577-82.
While Ig+ B cells appear to be the principal cell type expressing immunogenic minor lymphocyte stimulatory (Mls) determinants, both T cells and B cells are capable of mediating deletion of developing Mls-reactive thymocytes. In addition, levels of mouse mammary tumor proviral transcripts are increased after B or T cell stimulation, and expression of functional Mls determinants is augmented by activation of B cells. These findings suggest Mls determinants are present on B and T lymphocytes, and that activation of B and T cells augments Mls expression. In the present study, we wished to determine whether B and T cells were required for expression of Mls determinants by examining mice with severe combined immunodeficiency (SCID) containing no detectable Ig+ B cells or TCR+ T cells, as well as animals that expressed the X-linked immunodeficiency (xid) defect and lacked a subset of mature B cells. We found Mlsa-reactive V beta 6hi T cells were deleted from thymi of male (CBA/NxAKR/J)F1 xid mice, and that spleen cells from these animals stimulated anti-Mlsa mixed lymphocyte responses by unprimed B10.BR spleen T cells. In addition, Mlsc-reactive V beta 3hi AKR/J thymocytes and spleen T cells were deleted in AKR/J----SCID bone marrow chimeras, and spleen cells from SCID mice stimulated proliferation by an Mlsc-specific T cell clone. These results demonstrate that both xid mice and SCID animals express Mls determinants that mediate deletion of developing, Mls-responsive thymocytes and stimulate proliferation of mature, Mls-reactive T cells. Hence, mature B cells and T cells are not essential for Mls expression.
虽然Ig⁺ B细胞似乎是表达免疫原性次要淋巴细胞刺激（Mls）决定簇的主要细胞类型，但T细胞和B细胞都能够介导发育中的Mls反应性胸腺细胞的缺失。此外，B细胞或T细胞刺激后，小鼠乳腺肿瘤前病毒转录本水平升高，B细胞激活可增强功能性Mls决定簇的表达。这些发现表明Mls决定簇存在于B淋巴细胞和T淋巴细胞上，并且B细胞和T细胞的激活会增强Mls表达。在本研究中，我们希望通过检查没有可检测到的Ig⁺ B细胞或TCR⁺ T细胞的严重联合免疫缺陷（SCID）小鼠，以及表达X连锁免疫缺陷（xid）缺陷且缺乏成熟B细胞亚群的动物，来确定Mls决定簇的表达是否需要B细胞和T细胞。我们发现，雄性（CBA/NxAKR/J）F1 xid小鼠胸腺中Mlsa反应性Vβ6hi T细胞被删除，并且这些动物的脾细胞可刺激未致敏的B10.BR脾T细胞产生抗Mlsa混合淋巴细胞反应。此外，在AKR/J→SCID骨髓嵌合体中，Mlsc反应性Vβ3hi AKR/J胸腺细胞和脾T细胞被删除，并且SCID小鼠的脾细胞可被Mlsc特异性T细胞克隆刺激增殖。这些结果表明，xid小鼠和SCID动物都表达Mls决定簇，这些决定簇介导发育中的、对Mls有反应的胸腺细胞的缺失，并刺激成熟的、对Mls有反应的T细胞增殖。因此，成熟B细胞和T细胞对于Mls表达并非必不可少。
