Krzych U, Fowler A V, Miller A, Sercarz E E
Department of Biology, Catholic University of America, Washington, DC 20064.
FASEB J. 1988 Feb;2(2):141-5. doi: 10.1096/fasebj.2.2.2963778.
The fine specificity of the T cell repertoire directed against T helper (Th)-inducing and T suppressor (Ts)-inducing determinants was examined with cyanogen bromide and tryptic peptides of Escherichia coli beta-galactosidase (GZ), a large tetrameric protein (monomer molecular weight = 116 kDa). Immunization with cyanogen bromide fragment 2 [CB-2, amino acids (a.a.) 3-92] induced both specific Th and Ts cells. Study of the induction of these functionally opposite T cell subpopulations with tryptic peptides of CB-2 indicated that Th and Ts were activated by separate, nonoverlapping determinants. Th-inducing activity resided in a nonapeptide, T6 (a.a. 44-52), whereas T4 (a.a. 27-37) induced Ts cells. The presence of distinct helper and suppressor determinants suggests that the specificity repertoire in these T cell subpopulations may differ, perhaps owing to the expression of antigen-recognizing receptors that are coded by unique gene families. Alternatively, antigen presentation structures may be physicochemically quite different, and bind to distinct parts of the peptide antigen.
利用大肠杆菌β-半乳糖苷酶（GZ，一种大四聚体蛋白，单体分子量 = 116 kDa）的溴化氰和胰蛋白酶肽段，研究了针对辅助性T细胞（Th）诱导决定簇和抑制性T细胞（Ts）诱导决定簇的T细胞受体库的精细特异性。用溴化氰片段2 [CB-2，氨基酸（a.a.）3 - 92]免疫可诱导特异性Th细胞和Ts细胞。用CB-2的胰蛋白酶肽段对这些功能相反的T细胞亚群的诱导研究表明，Th细胞和Ts细胞由分开的、不重叠的决定簇激活。Th诱导活性存在于一个九肽T6（a.a. 44 - 52）中，而T4（a.a. 27 - 37）诱导Ts细胞。不同的辅助性和抑制性决定簇的存在表明，这些T细胞亚群中的特异性受体库可能不同，这可能是由于由独特基因家族编码的抗原识别受体的表达。或者，抗原呈递结构在物理化学性质上可能有很大差异，并与肽抗原的不同部分结合。
