Allen P M, Strydom D J, Unanue E R
Proc Natl Acad Sci U S A. 1984 Apr;81(8):2489-93. doi: 10.1073/pnas.81.8.2489.
The purpose of this study was to identify the fragment of the hen egg-white lysozyme (HEL) molecule presented by macrophages to helper T cells. This was investigated by using T-cell hybridomas and macrophages prefixed in paraformaldehyde. We previously had shown that such prefixed macrophages could present a tryptic digest of HEL. The tryptic peptides were separated by HPLC and tested for their ability to stimulate the T-cell hybridomas. Only one tryptic peptide was found to be immunogenic. This immunogenic peptide was identified as the tryptic peptide T-8, containing amino acids 46-61. The precise determinant on the peptide T-8 being recognized was further defined by testing the response of the two T-cell hybridomas to human lysozyme. Neither clone responded to human lysozyme. From the amino acid sequence of human lysozyme, the determinant was localized to the four amino-terminal residues. Cleavage of the immunogenic peptide with either chymotrypsin or protease V-8 completely abolished the immunogenicity. This suggested that the T-cell determinant is located in the hydrophilic amino-terminal residues and that it must be associated with a hydrophobic stretch of amino acids, which allows the peptide to associate with the macrophage plasma membrane.
本研究的目的是确定巨噬细胞呈递给辅助性T细胞的鸡蛋清溶菌酶（HEL）分子片段。通过使用T细胞杂交瘤和用多聚甲醛固定的巨噬细胞对此进行了研究。我们之前已经表明，这种固定的巨噬细胞可以呈递HEL的胰蛋白酶消化产物。通过高效液相色谱法分离胰蛋白酶肽，并测试它们刺激T细胞杂交瘤的能力。仅发现一种胰蛋白酶肽具有免疫原性。这种免疫原性肽被鉴定为包含氨基酸46 - 61的胰蛋白酶肽T - 8。通过测试两种T细胞杂交瘤对人溶菌酶的反应，进一步确定了肽T - 8上被识别的精确决定簇。两个克隆均未对人溶菌酶产生反应。根据人溶菌酶的氨基酸序列，该决定簇定位于四个氨基末端残基。用胰凝乳蛋白酶或蛋白酶V - 8切割免疫原性肽完全消除了免疫原性。这表明T细胞决定簇位于亲水性氨基末端残基中，并且它必须与一段疏水性氨基酸序列相关联，这使得该肽能够与巨噬细胞质膜结合。
