Ottaway C A
Department of Medicine, St. Michael's Hospital, University of Toronto, Canada.
Regul Pept. 1992 Sep 3;41(1):49-59. doi: 10.1016/0167-0115(92)90513-t.
The specific binding of vasoactive intestinal peptide (VIP) to murine lymphocytes was investigated. CD4 T cells from mesenteric lymph nodes (MLN) bound more 125I-VIP than did unseparated MLN lymphocytes at 37 degrees C, but not at 4 degrees C. The differences between the amount of 125I-VIP bound by the CD4 T cells and unseparated MLN lymphocytes at 37 degrees C depended upon a difference in the amount of the ligand that was internalized by the cells. The rate of insertion of unoccupied VIP receptors from the cytoplasm into the cell membrane (370 receptors/cell/min), the rate constants for internalization of ligand occupied VIP receptors (0.55 min-1) and unoccupied VIP receptors (0.11 min-1), and the rate constant for the elimination of internalized VIP (0.07 min-1) by CD4 T cells were evaluated. These results provide new understanding of the behaviour of VIP receptors on lymphocytes and indicate a mechanism by which CD4 T lymphocytes can homologously regulate their surface expression of VIP receptors in the presence of ambient VIP.
研究了血管活性肠肽（VIP）与小鼠淋巴细胞的特异性结合。在37℃时，来自肠系膜淋巴结（MLN）的CD4 T细胞比未分离的MLN淋巴细胞结合更多的125I-VIP，但在4℃时则不然。在37℃时，CD4 T细胞与未分离的MLN淋巴细胞结合的125I-VIP量的差异取决于细胞内化的配体量的差异。评估了未占据的VIP受体从细胞质插入细胞膜的速率（370个受体/细胞/分钟）、配体占据的VIP受体（0.55分钟-1）和未占据的VIP受体（0.11分钟-1）的内化速率常数，以及CD4 T细胞消除内化VIP的速率常数（0.07分钟-1）。这些结果为淋巴细胞上VIP受体的行为提供了新的认识，并表明在周围存在VIP的情况下，CD4 T淋巴细胞可以通过一种机制同源调节其VIP受体的表面表达。
