Sun D, Wilson D B, Cao L, Whitaker J N
Department of Neurology and the Center for Neuroimmunology of the University of Alabama at Birmingham, 35294, USA.
J Neuroimmunol. 1998 Jan;81(1-2):177-83. doi: 10.1016/s0165-5728(97)00176-8.
Adult Lewis (LEW) rats are highly susceptible to experimental autoimmune encephalomyelitis (EAE), induced actively by immunization with guinea pig (GP) myelin basic protein (MBP) in complete Freund's adjuvant or adoptively transferred with activated T lymphocytes reactive to GP MBP peptide 68-88. Once LEW rats recover from active EAE or when given MBP in incomplete Freund's adjuvant (IFA), they become resistant to further attempts to induce active or passive EAE. In this study, we examined whether such EAE-resistant rats after MBP-IFA immunization have reduced frequencies of MBP-reactive T cells, whether these T cells are anergized, and whether the activity of regulatory T cells is increased to the event that they prevent activation of MBP-specific T cell subpopulations. By limiting dilution analyses (LDA) of unfractionated splenic T cells, the levels of MBP-reactive T cells in EAE-resistant rats appeared to be approximately 5% of the levels in EAE-susceptible rats. However, a subsequent analysis of CD4+ enriched T cell populations, depleted of the CD8 subset, showed similar frequencies of MBP-reactive cells in susceptible and resistant LEW rats. Not only were the frequencies on LDA altered by suppressor cells, but also LDA comparisons based on cell proliferation and cytokine production as indicators of MBP reactive cell frequencies gave markedly different results. We conclude that MBP-reactive T cells in this model of EAE-resistant LEW rats are hyporeactive to MBP as the result of an increased activity of a regulatory subset of CD8+ T cells. These results also demonstrate that the quantitation of MBP-reactive CD4+ T cells by LDA is strongly influenced by the presence of functionally antagonistic CD8+ T cells, which cause an underestimation of responder T cell frequencies, and by the method of detecting T cell reactivity.
成年Lewis（LEW）大鼠对实验性自身免疫性脑脊髓炎（EAE）高度易感，通过在完全弗氏佐剂中用豚鼠（GP）髓鞘碱性蛋白（MBP）免疫可主动诱导发病，或通过过继转移对GP MBP肽68 - 88有反应的活化T淋巴细胞而发病。一旦LEW大鼠从主动EAE中恢复，或在不完全弗氏佐剂（IFA）中给予MBP时，它们就会对进一步诱导主动或被动EAE产生抗性。在本研究中，我们检查了经MBP - IFA免疫后的这种EAE抗性大鼠中，MBP反应性T细胞的频率是否降低，这些T细胞是否失能，以及调节性T细胞的活性是否增加到阻止MBP特异性T细胞亚群活化的程度。通过对未分级脾T细胞进行有限稀释分析（LDA），EAE抗性大鼠中MBP反应性T细胞的水平似乎约为EAE易感大鼠水平的5%。然而，随后对富集的CD4 + T细胞群体（去除了CD8亚群）的分析表明，易感和抗性LEW大鼠中MBP反应性细胞的频率相似。不仅LDA上的频率受到抑制细胞的影响，而且基于细胞增殖和细胞因子产生作为MBP反应性细胞频率指标的LDA比较也给出了明显不同的结果。我们得出结论，在这种EAE抗性LEW大鼠模型中，MBP反应性T细胞对MBP反应性降低是CD8 + T细胞调节亚群活性增加的结果。这些结果还表明，通过LDA对MBP反应性CD4 + T细胞进行定量受到功能拮抗的CD8 + T细胞的强烈影响，这会导致对反应性T细胞频率的低估，并且受到检测T细胞反应性方法的影响。
