Data are presented concerning peculiarities of human lymphocyte luminol-dependent chemiluminescence stimulated with C3b-opsonized and native zymosan. The response was maximal by the 60th min and 4-17 exceeded the results of the negative control. The C3b-opsonization considerably potentiated the lymphocyte activating zymosan's properties and the rate of reaction/maximal level at the 10th min; the effect of phytohemagglutinin reached max by the end of the 1st min in the same tests. The functional significance of the CR- and lectin-mediated structures of lymphocytes is discussed.