Potentiation of the cellular immune response by adjuvants: a limited role for adjuvant induced interferon.
Adjuvants differ in capacity to induce interferon (IFN). As a consequence IFN induction by adjuvants may influence their effectiveness in enhancement of delayed type hypersensitivity (DH) reactions. In this study, the lipophilic amine dimethyl dioctadecyl ammonium bromide (DDA), the synthetic double-stranded polynucleotide polyinosinic polycytidylic acid (poly I:C), liposomes and the polyols L 101 and L 121 were compared in BALB/c mice as inducers of IFN and also as adjuvants for DH to both lysozyme and inactivated Semliki Forest virus (SFV). The antigens were injected intracutaneously, alone or mixed with adjuvant. At day 6 after the immunization, DH was elicited and measured 24 h later as increase in footpad thickness. Negatively charged liposomes and polyol L 121 were unable to enhance DH to SFV and also lack the capacity to induce IFN. Polyol L 101 induced low levels of IFN and showed only slight adjuvanticity for DH to SFV. In contrast, DDA, a moderate IFN inducer, was shown to be a very effective adjuvant for induction of DH against both lysozyme and SFV. The excellent IFN inducer, poly I:C, at the tested dose range (0.03-3.0 mg/kg), displayed only a relatively weak adjuvant activity. But low doses of poly I:C (0.03 and 0.1 mg/kg) showed still adjuvanticity in contrast to equal doses of DDA. This might be related to sufficient induction of IFN by low doses of poly I:C but not by DDA. The discrepancy observed in the relation between IFN induction and a maximal DH induction suggests that IFN is not the only factor which enhances the effectiveness of adjuvants in induction of DH.(ABSTRACT TRUNCATED AT 250 WORDS)
D000276:Adjuvants, Immunologic / Q000276:immunology*; D000818:Animals; D000917:Antibody Formation; D004306:Dose-Response Relationship, Immunologic; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D007111:Immunity, Cellular; D007372:Interferons / Q000096:biosynthesis*; D008081:Liposomes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011070:Poly I-C / Q000276:immunology; D011108:Polymers / Q000276:immunology; D000644:Quaternary Ammonium Compounds / Q000276:immunology
D000276:Adjuvants, Immunologic; D008081:Liposomes; D011108:Polymers; D000644:Quaternary Ammonium Compounds; C024617:polyol; C015831:dimethyldioctadecylammonium; D007372:Interferons; D011070:Poly I-C