Tartakovsky B, Durum S K
Yale J Biol Med. 1985 Mar-Apr;58(2):145-52.
Individual murine B cells express a wide range of Ia densities on the plasma membrane. Here we demonstrate that a dramatic increase in B-cell Ia could be induced by overnight exposure to an uncharacterized lymphokine (LK). Membrane I-A and I-E molecules were both increased after LK treatment, whereas membrane IgM remained unchanged. Two subpopulations of B cells were identified, based on their requirements for expressing maximal Ia; one subpopulation required only LK, the other required both LK and T cells in the overnight culture. Functional changes accompanied the Ia increase. The functional capacity to present antigens to T cells was lacking in normal resting B cells, but was acquired following LK treatment. We suggest that the LK-treated B cell has achieved a new differentiation state, one of preparation for interaction with T cells. We term this state the "poised" B cell, and propose that B cells in the poised state may significantly contribute to T-cell activation as antigen-presenting cells. Moreover, poised B cells may themselves find an advantage over normal B cells in successfully acquiring T-cell help.
单个小鼠B细胞在质膜上表达多种Ia密度。在此我们证明，通过过夜暴露于一种未鉴定的淋巴因子（LK）可诱导B细胞Ia显著增加。LK处理后，膜I-A和I-E分子均增加，而膜IgM保持不变。根据表达最大Ia的需求，鉴定出两个B细胞亚群；一个亚群仅需要LK，另一个亚群在过夜培养中既需要LK也需要T细胞。功能变化伴随着Ia增加。正常静止B细胞缺乏向T细胞呈递抗原的功能能力，但在LK处理后获得了该能力。我们认为，经LK处理的B细胞达到了一种新的分化状态，即准备与T细胞相互作用的状态之一。我们将这种状态称为“准备就绪”的B细胞，并提出处于准备就绪状态的B细胞作为抗原呈递细胞可能对T细胞激活有显著贡献。此外，准备就绪的B细胞自身在成功获得T细胞辅助方面可能比正常B细胞具有优势。
