Kakiuchi T, Takatsuki A, Watanabe M, Nariuchi H
Department of Allergology, University of Tokyo, Japan.
J Immunol. 1991 Nov 15;147(10):3289-95.
We have shown previously that specific Ag presentation is prevented by the inhibition of protein synthesis but nonspecific presentation is not. In the present paper, Ag presentation by Ag-specific B cells was examined for sensitivity to brefeldin A (BFA), which blocks protein export from the endoplasmic reticulum. A20-HL B lymphoma expressing surface receptors specific for TNP was used as a B cell, and TNP-OVA was used as a specific Ag. The presence of BFA during pulsing of A20-HL cells with TNP-OVA inhibited the ability of the pulsed cells to stimulate 42-6A T cell clone, specific for OVA323-339 and Iad. The inhibition was not due to nonspecific toxicity of BFA, because the presence of BFA during pulsing of A20-HL cells with OVA323-339 did not affect their APC function. Ag binding to the receptor on A20-HL cells and internalization by the cells were observed in the presence of BFA. Thus, BFA might inhibit intracellular processing of specific Ag or intracellular complex formation of antigenic peptide from specific Ag with MHC class II molecules. Nonspecific Ag presentation by A20-HL cells, however, was resistant to BFA. A20-HL cells pulsed with OVA in the presence of BFA, even after fixation, could stimulate 42-6A cells to produce IL-2, although the IL-2 production was lower than that induced by A20-HL cells pulsed in the absence of BFA. These results suggest that the processing pathways for specific Ag and nonspecific Ag are different from each other, at least partly, in A20-HL cells.
我们之前已经表明，蛋白质合成的抑制可阻止特异性抗原呈递，但非特异性抗原呈递则不受影响。在本文中，我们检测了抗原特异性B细胞的抗原呈递对布雷菲德菌素A（BFA）的敏感性，BFA可阻断蛋白质从内质网的输出。表达对三硝基苯（TNP）具有特异性表面受体的A20-HL B淋巴瘤用作B细胞，TNP-卵清蛋白（OVA）用作特异性抗原。在用TNP-OVA脉冲A20-HL细胞的过程中加入BFA，抑制了脉冲细胞刺激对OVA323-339和Iad具有特异性的42-6A T细胞克隆的能力。这种抑制不是由于BFA的非特异性毒性，因为在用OVA323-339脉冲A20-HL细胞的过程中加入BFA并不影响它们的抗原呈递细胞（APC）功能。在有BFA存在的情况下，观察到抗原与A20-HL细胞上的受体结合并被细胞内化。因此，BFA可能抑制特异性抗原的细胞内加工或特异性抗原的抗原肽与II类主要组织相容性复合体（MHC）分子的细胞内复合物形成。然而，A20-HL细胞的非特异性抗原呈递对BFA具有抗性。即使在固定后，在有BFA存在的情况下用OVA脉冲的A20-HL细胞仍可刺激42-6A细胞产生白细胞介素-2（IL-2），尽管IL-2的产生低于在无BFA情况下脉冲的A20-HL细胞所诱导的水平。这些结果表明，在A20-HL细胞中，特异性抗原和非特异性抗原的加工途径至少部分是不同的。
