Fujihashi K, Taguchi T, McGhee J R, Eldridge J H, Bruce M G, Green D R, Singh B, Kiyono H
Department of Oral Biology, University of Alabama, Birmingham 35294.
J Immunol. 1990 Oct 1;145(7):2010-9.
The murine intraepithelial lymphocyte (IEL) population is enriched in T cells that express the gamma delta-TCR, however, the biologic function served by these T cells remains obscure. IEL are considered to be major effector cells in mucosal immunity, and we have investigated whether IEL subsets could reverse orally induced systemic unresponsiveness (oral tolerance; OT) and support secondary type responses when adoptively transferred to mice orally tolerized with SRBC. When purified CD3+ IEL from mice orally primed with SRBC were transferred to adoptive hosts and challenged with SRBC, splenic IgM, IgG1, IgG2b, and IgA anti-SRBC plaque-forming cell responses were observed. However, CD3+ IEL from HRBC orally primed mice did not abrogate SRBC induced OT. Further, HRBC-primed CD3+, IEL converted HRBC-specific OT but not SRBC-specific OT. CD3+ IEL could be separated into four subsets based on expression of CD4 and CD8. CD3+, CD4-, 8+ T cells were the major subset (74.5%), with smaller numbers of CD4- and CD8- (double negatives, DN) (7.8%), CD4+, 8- (7.6%) and CD4+, CD8+ (double positives) (10.1%) T cells. Interestingly, both the CD3+, CD8+, and the CD3+, DN IEL subsets abrogated OT, resulting in significant IgM, IgG1, IgG2b, and IgA anti-SRBC plaque-forming cell responses when adoptively transferred to mice with OT. However, neither CD3+, CD4+, CD8-, nor double positive T cells affected OT when studied in this system. The CD3+, CD8+ IEL subset could be further separated into Thy-1+ (16.6%) and Thy-1- (83.4%) cells; adoptive transfer of Thy-1- cells abrogated oral tolerance whereas the Thy-1+ subset was without effect. When the expression of TCR on IEL with this biologic function was determined by use of monoclonal anti-alpha beta TCR (H57.597), TCR2-, CD3+ IEL possessed immunoregulatory function whereas the alpha beta-TCR+ (TCR2+) fraction did not abrogate OT. Immunoprecipitation of membrane fractions obtained from purified CD3+, CD4-, CD8+, Thy-1- IEL with polyclonal anti-delta peptide (Tyr-Ala-Asn-Ser-Phe-Asn-Asn-Glu-Lys-Leu) antibody revealed bands of 45 and 35 kDa, corresponding to the delta- and gamma-chains, respectively. These results suggest that gamma delta-TCR+ IEL possess a regulatory function, namely the restoration of immune responses in a state of oral tolerance. Further, both CD3+, CD4-, CD8+, Thy-1-, and CD3+, DN IEL T cells exhibit this effector contrasuppressor function.
小鼠上皮内淋巴细胞（IEL）群体富含表达γδ-TCR的T细胞，然而，这些T细胞所发挥的生物学功能仍不清楚。IEL被认为是黏膜免疫中的主要效应细胞，我们研究了IEL亚群是否能逆转口服诱导的全身无反应性（口服耐受；OT），并在将其过继转移到经SRBC口服耐受的小鼠后是否能支持二次型反应。当将经SRBC口服致敏小鼠的纯化CD3⁺ IEL过继转移到受体宿主并用SRBC攻击时，观察到脾脏中IgM、IgG1、IgG2b和IgA抗SRBC斑块形成细胞反应。然而，经HRBC口服致敏小鼠的CD3⁺ IEL并不能消除SRBC诱导的OT。此外，经HRBC致敏的CD3⁺ IEL能逆转HRBC特异性OT，但不能逆转SRBC特异性OT。基于CD4和CD8的表达，CD3⁺ IEL可分为四个亚群。CD3⁺、CD4⁻、8⁺ T细胞是主要亚群（74.5%），CD4⁻和CD8⁻（双阴性，DN）（7.8%）、CD4⁺、8⁻（7.6%）和CD4⁺、CD8⁺（双阳性）（10.1%）T细胞数量较少。有趣的是，CD3⁺、CD8⁺和CD3⁺、DN IEL亚群都能消除OT，当将其过继转移到有OT的小鼠时，会导致显著的IgM、IgG1、IgG2b和IgA抗SRBC斑块形成细胞反应。然而，在该系统中研究时，CD3⁺、CD4⁺、CD8⁻和双阳性T细胞均不影响OT。CD3⁺、CD8⁺ IEL亚群可进一步分为Thy-1⁺（16.6%）和Thy-1⁻（83.4%）细胞；过继转移Thy-1⁻细胞可消除口服耐受，而Thy-1⁺亚群则无此作用。当使用单克隆抗αβ-TCR（H57.597）确定具有这种生物学功能的IEL上TCR的表达时，TCR2⁻、CD3⁺ IEL具有免疫调节功能，而αβ-TCR⁺（TCR2⁺）部分不能消除OT。用多克隆抗δ肽（Tyr-Ala-Asn-Ser-Phe-Asn-Asn-Glu-Lys-Leu）抗体对从纯化的CD3⁺、CD4⁻、CD8⁺、Thy-1⁻ IEL获得的膜组分进行免疫沉淀，显示出45 kDa和35 kDa的条带，分别对应于δ链和γ链。这些结果表明，γδ-TCR⁺ IEL具有调节功能，即在口服耐受状态下恢复免疫反应。此外，CD3⁺、CD4⁻、CD8⁺、Thy-1⁻和CD3⁺、DN IEL T细胞均表现出这种效应性抗抑制功能。
