Finkel T H, McDuffie M, Kappler J W, Marrack P, Cambier J C
Department of Immunology, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206.
Nature. 1987;330(6144):179-81. doi: 10.1038/330179a0.
T cells develop from prothymocytes which express no detectable antigen receptors to immature thymocytes with few receptors, eventually becoming mature thymocytes and peripheral T cells with 20,000-40,000 receptors per cell. Recent studies suggest that immature thymocytes are immunologically unresponsive. We have suggested that an early step in signal transduction following engagement of the T cell receptor might differ in immature and mature T cells. Here we examine anti-receptor antibody mediated induction of calcium mobilization in immature and mature T cells. Results indicate that antigen receptors on both immature and mature receptor-positive T cells transduce signals via calcium mobilization. Significant differences were observed, however, between these populations in the magnitude of influx of extracellular Ca2+ following binding of antireceptor antibody. Specifically immature cells show a much reduced Ca2+ influx response compared to mature cells which could result from a low Ca2+ channel frequency in the plasma membranes of immature T cells, or from less efficient activation of existing channels.
T细胞由不表达可检测到的抗原受体的原胸腺细胞发育而来，成为受体较少的未成熟胸腺细胞，最终发育为成熟胸腺细胞和外周T细胞，每个细胞有20000 - 40000个受体。最近的研究表明，未成熟胸腺细胞在免疫上无反应性。我们曾提出，T细胞受体结合后信号转导的早期步骤在未成熟和成熟T细胞中可能有所不同。在此，我们检测抗受体抗体介导的未成熟和成熟T细胞中钙动员的诱导情况。结果表明，未成熟和成熟的受体阳性T细胞上的抗原受体都通过钙动员来转导信号。然而，在抗受体抗体结合后，这些细胞群体在细胞外Ca2+内流的幅度上存在显著差异。具体而言，与成熟细胞相比，未成熟细胞的Ca2+内流反应大大降低，这可能是由于未成熟T细胞质膜中Ca2+通道频率较低，或者是由于现有通道的激活效率较低所致。
