Castiglioni Paola, Gerloni Mara, Cortez-Gonzalez Xochitl, Zanetti Maurizio
The Department of Medicine and Cancer Center, University of California in San Diego, La Jolla, USA.
Eur J Immunol. 2005 May;35(5):1360-70. doi: 10.1002/eji.200425530.
While it is generally accepted that B lymphocytes can present antigen and activate CD4 T cells, priming of CD8 T cells by B lymphocytes remains controversial. Recently, we showed that mice injected with genetically programmed B lymphocytes generate antigen specific CD4 and CD8 T cell responses in vivo that could also be induced in mice lacking functional dendritic cells. To gain further insights into the requirements for T cell priming by antigen-presenting B lymphocytes, in vitro experiments were performed using ovalbumin (OVA) and OVA-specific TCR-transgenic CD4 and CD8 T cells. We found that while B lymphocytes can directly prime CD4 T cells, the activation of CD8 T cells requires T cell help. Transfer experiments show that help can either be contact dependent or be mediated by soluble factors in the supernatants of activated OVA-specific CD4 T cells. Furthermore, the effect of activated CD4 T cells can be replaced by soluble recombinant IL-4. Collectively, the data show the existence of different requirements for priming of CD4 and CD8 T cells and point to the previously unappreciated fact that the induction of CD8 T cell responses by B lymphocytes requires T cell help.
虽然人们普遍认为B淋巴细胞能够呈递抗原并激活CD4 T细胞，但B淋巴细胞对CD8 T细胞的启动作用仍存在争议。最近，我们发现，注射了基因编程B淋巴细胞的小鼠在体内产生了抗原特异性CD4和CD8 T细胞反应，在缺乏功能性树突状细胞的小鼠中也能诱导出这种反应。为了进一步深入了解抗原呈递B淋巴细胞启动T细胞的条件，我们使用卵清蛋白（OVA）以及OVA特异性TCR转基因CD4和CD8 T细胞进行了体外实验。我们发现，虽然B淋巴细胞可以直接启动CD4 T细胞，但CD8 T细胞的激活需要T细胞的辅助。转移实验表明，这种辅助可以是接触依赖性的，也可以由活化的OVA特异性CD4 T细胞上清液中的可溶性因子介导。此外，活化的CD4 T细胞的作用可以被可溶性重组白细胞介素-4所替代。总体而言，这些数据表明CD4和CD8 T细胞启动存在不同条件，并指出了一个此前未被重视的事实，即B淋巴细胞诱导CD8 T细胞反应需要T细胞的辅助。
