EXPRESSION OF IA ANTIGENS ON FUNCTIONAL CELL SUBPOPULATIONS

克隆和异质性T细胞群体对 有丝分裂原和特异性抗原刺激物被发现需要 表达Ia（I）的辅助细胞或抗原呈递细胞的参与 区域相关的）决定因素。 研究旨在分析 对Ia分子上的特定决定簇的功能重要性进行了研究 使用一系列单克隆抗I-E试剂， 相同I-E产物分子上的不同表位。 一系列T细胞 克隆识别与一种抗原结合的相同抗原分子， 研究了给定I-E分子对抑制的敏感性， 一组15种不同的抗I-E单克隆抗体， 同一个I-E分子上的决定簇 结果表明 不同的T细胞克隆似乎识别与 同一I-E分子上不同的决定簇或构象。 的 T细胞克隆对有丝分裂原关节炎支原体的反应 分析上清液（MAS）。 据统计，约15% 的测试克隆响应MAS时，在I-E的背景下， 携带抗原呈递细胞，并且这种反应性是独立的， 这些克隆的主要特异性或MHC限制， 常规抗原。 不同Ia表达群体的能力 评估呈递给克隆的T细胞的能力。 所有测试的克隆都是 能够对含有粘附细胞的辐射刺激细胞作出反应，或 至丝裂霉素处理的纯化的静息B细胞群。 与此相反， 只有克隆的T细胞亚群对LPS激活的B有应答 尽管这些B细胞的Ia表达增强， 爆炸声 这些发现表明T细胞所需的信号 活化在T细胞克隆中可能不同，并且不同的Ia携带者 抗原提呈细胞可能有能力呈递给不同的T细胞， 细胞 采用克隆Ia+ B细胞淋巴瘤和 杂交瘤还表明T细胞在其免疫应答中的异质性。 对这些人群的反应。

The responses of both cloned and heterogeneous T cell populations to mitogens and specific antigenic stimuli were found to require the participation of accessory or antigen presenting cells which express Ia (I region associated) determinants. Studies designed to analyze the functional importance of specific determinants on Ia molecules were carried out employing a battery of monoclonal anti I-E reagents specific for different epitopes on the same I-E product molecule. A series of T cell clones which recognized the same antigenic molecule in association with a given I-E molecule were studied for their susceptibility to inhibition by a panel of 15 different anti I-E monoclonal antibodies specific for determinants on the same I-E molecule. The results demonstrated that different T cell clones appear to recognize antigen in association with distinct determinants or conformations on the same I-E molecule. The responses of T cell clones to the mitogen Mycoplasma arthritidis supernatant (MAS) were analyzed. It was determined that approximately 15% of the clones tested responded to MAS when presented in the context of I-E bearing antigen presenting cells, and that this reactivity was independent of the primary specificity or MHC restriction of those clones to conventional antigens. The ability of different Ia expressing populations to present to cloned T cells was evaluated. All of the clones tested were able to respond to adherent cell-containing irradiated stimulating cells or to mitomycin treated purified resting B cell populations. In contrast, only a subpopulation of cloned T cells was responsive to LPS activated B cell blasts, in spite of the enhanced Ia expression by these B cell blasts. These findings indicate that the signals required for T cell activation may vary among T cell clones, and that distinct Ia bearing antigen presenting cells may be competent for presentation to different T cells. Additional studies employing cloned Ia+ B cell lymphomas and hybridomas also indicate a heterogeneity among T cells in their responsiveness to these populations.