Potentiation of antitumor activity of macrophages by recombinant interferon alpha A/D contained in gelatin microspheres.
Gelatin microspheres containing recombinant human interferon alpha A/D (A/D-IFN) (IFN-microspheres) potentiated the antitumor activity of mouse peritoneal macrophages (M phi) much more efficiently than free A/D-IFN. M phi acquired the inhibitory activity on tumor cell growth by the ingestion of IFN-microspheres without the aid of lipopolysaccharide (LPS), though LPS was required as a second signal for activating M phi primed with free IFN. The IFN-microspheres were much more efficient than free IFN plus LPS in respect of the IFN amount and the time required for M phi activation. Furthermore, M phi pretreated with the IFN-microspheres maintained their activated state for a much longer period than those pretreated with free A/D-IFN plus LPS. A monoclonal anti-IFN-alpha A antibody, which was capable of neutralizing A/D-IFN, did not interfere with the M phi activation by the IFN-microspheres. Even human IFN-alpha A was effective in activating murine M phi similarly to A/D-IFN, when given in the form of IFN-microspheres, though human IFN-alpha A in the free form was ineffective. These results argue that the mechanism of M phi activation by the IFN-microspheres is different from that by free IFN.
D000818:Animals; D005260:Female; D005780:Gelatin; D007370:Interferon Type I / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008854:Microscopy, Electron; D008863:Microspheres; D010587:Phagocytosis / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology; D013045:Species Specificity
D007370:Interferon Type I; D011994:Recombinant Proteins; D005780:Gelatin