Nonspecific human lymphocyte-mediated cytotoxicity induced by immobilized IgG aggregate

Fc receptor--more answers, more questions

Fc receptors, belonging to the most important surface structures of a number of cells participating in the immune processes, have been intensely studied during the past decade. The present review summarizes the contemporary knowledge of the specificity and heterogeneity of Fc receptors and of factors influencing their expression, and includes some views on their function. In addition, it mentions their relationship to other cell surface structures, expression of Fc receptors during ontogeny of the organism and in certain diseases. Finally, data concerning the isolation and biochemical characterization of the Fc receptor molecule are presented.

Effect of Fc receptor blocking on human natural and lectin-dependent cell-mediated cytotoxicity against adherent HEp-2 cells

The effect of Fc receptor (FcR) blocking by aggregated human gamma-globulin (AGG) was studied on natural (NCMC) and lectin-dependent cell-mediated cytotoxicity (LDCC) against adherent HEp-2 human epipharynx carcinoma target cells. Cytotoxicity was measured by detachment from the monolayer of [3H]TdR-prelabelled HEp-2 cells. LDCC was evaluated in a 24 h assay at 50:1 effector-target cell ratio in the presence of 25 micrograms/ml concanavalin A (Con A). Under these conditions but without Con A considerable NCMC was not elicited by normal lymphocytes. FcR blocking by AGG treatment of effector cells resulted in a significant NCMC activity to HEp-2 targets. In contrast, AGG treatment profoundly depressed LDCC. Monocyte depletion of effector cells had no major influence on the effect of AGG on NCMC and LDCC activities. An interference of FcR blocking by AGG and LDCC in response to Con A is suggested.