Youseffi-Etemad R, Axelsson B
Department of Immunology, Stockholm University, Sweden.
Immunology. 1996 Mar;87(3):439-46.
Human peripheral blood T cells form large aggregates when cultured in the presence of antibodies to the highly sialylated protein CD43. About 25% of the cells in such cultures do not aggregate, however, although virtually all T cells express CD43. To find out if these cells constitute a distinct subpopulation of T cells, we analysed the expression of CD43 and lymphocyte function-associated antigen-1 (LFA-1) and examined the aggregation induced by CD43 monoclonal antibodies (mAb) in CD4+ and CD8+ cells and in their CD45RA+ (naive) and CD45RO+ (memory) subsets, respectively. We found that CD43-stimulated CD8+ cells aggregated more rapidly and formed larger aggregates than CD4+ cells. Furthermore, whereas CD8+CD45RO+ cells formed compact clusters after some hours of incubation, a majority (about 75%) of the CD4+CD45RA+ cells remained as singles even after overnight culture. Flow cytometry analysis showed that the patterns of expression of CD43 and of LFA-1 on the different subsets were strikingly parallel to each other. Thus, CD4+ and CD8+ memory (CD45RO+) T cells expressed higher levels of CD43 than the corresponding naive cells, suggesting that increased levels of CD43 expression are, like LFA-1 expression, a marker of primed or recently activated cells. Immunoprecipitation and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of 125I-labelled subsets showed that CD8+ cells expressed about twice as much CD43 as CD4+ cells. In a particular donor where the mean size of the cells in the four subsets was close to equal, CD4+ memory cells showed a 1.4-fold and CD8+ memory cells a twofold increase in CD43 compared to their corresponding naive populations. The propensity of memory T cells to extravasate may be facilitated by high expression of CD43.
当在存在针对高度唾液酸化蛋白CD43的抗体的情况下培养时，人外周血T细胞会形成大的聚集体。然而，尽管几乎所有T细胞都表达CD43，但在这种培养物中约25%的细胞不会聚集。为了弄清楚这些细胞是否构成T细胞的一个独特亚群，我们分析了CD43和淋巴细胞功能相关抗原-1（LFA-1）的表达，并分别检测了CD43单克隆抗体（mAb）在CD4⁺和CD8⁺细胞及其CD45RA⁺（初始）和CD45RO⁺（记忆）亚群中诱导的聚集情况。我们发现，与CD4⁺细胞相比，CD43刺激的CD8⁺细胞聚集得更快，形成的聚集体更大。此外，孵育数小时后，CD8⁺CD45RO⁺细胞形成紧密的簇，而即使过夜培养后，大多数（约75%）的CD4⁺CD45RA⁺细胞仍保持单个状态。流式细胞术分析表明，不同亚群上CD43和LFA-1的表达模式彼此显著平行。因此，CD4⁺和CD8⁺记忆（CD45RO⁺）T细胞比相应的初始细胞表达更高水平的CD43，这表明CD43表达水平的增加，与LFA-1表达一样，是已致敏或最近激活细胞的一个标志物。对¹²⁵I标记亚群的免疫沉淀和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析表明，CD8⁺细胞表达的CD43量约为CD4⁺细胞的两倍。在一个特定供体中，四个亚群中细胞的平均大小接近相等，与相应的初始群体相比，CD4⁺记忆细胞的CD43增加了1.4倍，CD8⁺记忆细胞增加了两倍。记忆T细胞的外渗倾向可能因CD43的高表达而得到促进。
