ROLE OF LFA-1/ICAM-1 IN THE ACTIVATION OF MURINE THYMOCYTES STIMULATED BY CON A
Lu Li-sheng Chen Wei-feng (Department of Immunology, Beijing Medical University, Beijing 100083)
The biological significance of the signals triggered by the interaction of cell surface expressed LFA-l and ICAM-1 has been investigated in Con A stimulated mu-rine thymocytes. Addition of anti-LFA-1 or/and anti-ICAM-1 McAb to the thymo-cyte culture in the presence of Con A, the cell proliferation was profoundly inhibited. Such inhibitory effect was more significant by the addition of anti-LFA-1 than by the addition of anti-ICAM-l McAb. FACS analysis revealed that the proliferation of CD8+ T cells was more sensitive to the inhibitory effect of anti-LFA-l McAb than did the proliferation of CD4+ T cells. The anti-LFA-1 McAb imposed inhibitory effect, however, could be reversed by the supplementation of IL-2 in the initiation of the culture. The proliferation of cultured Con A activated T blast cells could no longer be inhibited by the addition of anti-LFA-l McAb. Furthermore, neither anti-LFA-l nor anti-ICAM-1 McAb could block PMA + A23187 induced thymocyte proliferation. The results imply that the ligand-receptor pair of LFA-l-ICAM-1 molecules also takes part in the early events of Con A activated signal transduction pathway which leads to the proliferation of thymocytes.