Characterization of antibody-mediated inhibition of natural killer (NK) cytotoxicity: evidence for blocking of both recognition and lethal hit stages of cytolysis

Cellular Immunology
R KahleB Bonavida

Abstract

Rat antisera prepared against murine, periodate-activated alloimmune cytotoxic lymphocytes (termed RAT) have previously been shown to effectively block T-cell-mediated cytotoxicity (CMC) at the "lethal hit" stage of cytolysis (J.C. Hiserodt and B. Bonavida, J. Immunol. 126, 256, 1981). Both natural killer (NK) and cytotoxic T lymphocytes (CTL) have been shown to mediate lysis by the same pathway, namely binding of effector to target cells, programming for lysis, and killer cell-independent target cell lysis. This result suggested that the molecular mechanism of NKCMC and CTLCMC may also be similar. In this context, RAT-mediated blocking of CTL was examined for its ability to block NKCMC. The results show that (1) addition of RAT serum or IgG fractions blocked NKCMC in the absence of complement in a 4-hr 51CR-release assay, and blocking was directed at the effector cell; (2) at the single-cell level, RAT serum blocked the formation of conjugates between effector and target cells; (3) in a Ca2+-pulse experiment, in which the effectors and targets were first allowed to bind in the absence of Ca2+ for 1 hr at 37 degrees C, followed by the addition of Ca2+ to initiate the lytic event, RAT was capable of blocking cytotoxicity after c...Continue Reading

Citations

Jan 1, 1990·Developmental and Comparative Immunology·M GhoneumI Sadek
Jan 1, 1987·Developmental and Comparative Immunology·M H Ghoneum, E L Cooper
Jan 1, 1985·Developmental and Comparative Immunology·R L CarlsonS S Graves
Oct 26, 1988·Journal of Immunological Methods·S A GrandoO F Senyuk
Nov 5, 1987·Journal of Immunological Methods·L M Cosentino, M K Cathcart
Jan 1, 1983·Immunological Reviews·B BonavidaH Wexler

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