IL-12- mediated activation of MHC- unrestricted cytotoxicity of human PBMC subpopulations: Synergic action of a plant rhamnogalacturonan

Journal/Book: Anticancer Research 15, 2511-2516. 1995;

Abstract: IL-12 mediated activation of human MHC-unrestricted cytotoxicity wasstudied with freshly isolated, highly enriched CD56 +CD3- NK cells(95.98%), monocytes/macrophages (90-95%) and CD3 + T cells (95-98%).Activation of NK cell cytotoxicity and monocyte cytotoxicity by IL-12were independent of exogenous IL-2 and IFN gamma. Activation of CD3+Tcells to MHC-unrestricted cytotoxicity required coactivation by anti-CD3antibody. The enhanced cytotoxicities were directed against NK-sensitiveas well as NK-resistant target cells and coincided with enhancement ofeffector cell/target cell conjugate formation. The specific cytotoxicityof all three activated effector cell populations was further increasedin the presence of rhamnogalacturonan. These increases were based on anadditional increase of effector cell/target cell conjugate formationthat is based on rhamnogalacturonan-mediated bridging between effectorcells and target cells. Simultaneous enhancement of cytotoxicityindicates involvement of receptors on effector cells cross-reacting withacetylrhamnose (6-deoxymannose) that might play an important role inhuman MHC-unrestricted cytotoxicity against tumor cells. Author.

Keyword(s): ADJUVANTS-IMMUNOLOGIC/ PD (pharmacology)

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