Streilein J W, Grammer S F
Department of Microbiology and Immunology, University of Miami School of Medicine, FL 33101.
J Immunol. 1989 Dec 15;143(12):3925-33.
Monodisperse suspensions of epidermal Langerhans cells (LC) have been examined for their capacity to process and present Ag immediately upon extraction from mouse epidermis (fresh LC) and after 72 h in tissue culture (cultured LC). Cultured, but not fresh, LC stimulated proliferation among autologous T cells, whereas fresh, but not cultured, LC proved to be superior at processing native OVA for presentation to an OVA peptide-specific, MHC-restricted T cell hybridoma. Cultured LC were also more effective at stimulating proliferation among allogeneic T cells. However, a significant, but difficult to quantify, component of lymphocyte activation in these assays was derived from the ability of cultured LC to stimulate autologous T cells. It has been proposed that the superior capacity of cultured LC to stimulate T cells in these assays is due to the "immaturity" of freshly prepared LC--which "mature" during the 72-h culture interval. Based on the observation that fresh LC are superior at processing native protein Ag, we would amend the currently held notion that there is a "precursor-product" relationship between fresh and cultured LC to include the fact that these populations are differentially equipped to carry out distinct physiologic functions and that fresh LC should not, therefore, be considered "immature." We propose that fresh LC (in vitro equivalents of intraepidermal LC) can process native protein Ag with great efficiency, and can present these Ag in situ to memory and effector T cells (high affinity TCR interactions). Cultured LC (in vitro equivalents of LC that have migrated from skin to draining lymph node) exchange highly efficient Ag processing for acquisition of accessory molecules (surface ligands and secreted cytokines) that promote activation of unprimed T cells (including even low affinity TCR interactions).
对表皮朗格汉斯细胞（LC）的单分散悬浮液进行了检测，以研究其在从小鼠表皮提取后立即（新鲜LC）以及在组织培养72小时后（培养的LC）处理和呈递抗原的能力。培养的而非新鲜的LC刺激自体T细胞增殖，而新鲜的而非培养的LC在处理天然卵清蛋白（OVA）以呈递给OVA肽特异性、MHC限制性T细胞杂交瘤方面表现更优。培养的LC在刺激同种异体T细胞增殖方面也更有效。然而，在这些检测中，淋巴细胞激活的一个显著但难以量化的成分源自培养的LC刺激自体T细胞的能力。有人提出，在这些检测中培养的LC刺激T细胞的能力更强是由于新制备的LC“不成熟”，它们在72小时的培养间隔中“成熟”。基于新鲜LC在处理天然蛋白质抗原方面表现更优这一观察结果，我们将修正目前关于新鲜LC和培养的LC之间存在“前体-产物”关系的观念，以纳入这样一个事实，即这些细胞群体具备不同的能力来执行不同的生理功能，因此新鲜LC不应被视为“不成熟”。我们提出，新鲜LC（表皮内LC的体外等效物）能够高效处理天然蛋白质抗原，并能在原位将这些抗原呈递给记忆性和效应性T细胞（高亲和力TCR相互作用）。培养的LC（从皮肤迁移至引流淋巴结的LC的体外等效物）将高效的抗原处理能力换成了获得促进未致敏T细胞激活的辅助分子（表面配体和分泌的细胞因子）（甚至包括低亲和力TCR相互作用）。
