HUMORAL IMMUNE-RESPONSES TO SYSTEMIC CANDIDA-ALBICANS INFECTION IN INBRED MOUSE STRAINS

The protective role of humoral antibodies in the resolution of systemi c candidiasis remains controversial. Investigation of the humoral immu ne responses in mouse strains of varying susceptibility to infection m ay demonstrate a link between mouse strain susceptibility, antibody pr oduction and specificity, and the ability to resolve an infection. The antibody response in five different strains of mice during a primary imune response to systemic infection with Candida albicans was investi gated. Immune sera were fractionated by protein A affinity chromatogra phy to yield fractions containing IgG1, IgG2a and IgGZb immunoglobulin s. BALB/c mice of low susceptibility to the infection and DB4/2J mice of high susceptibility produced increased levels of the IgG1 isotype a nd decreased levels of the IgG2a isotype. AKR, CBA/H and C57B1/6J mice of moderate susceptibility produced antibodies predominantly of the I gG2a isotype. The patterns of antigen recognition by antibodies in imm une sera and in fractions obtained after protein A chromatography of i mmune sera were investigated by western blotting and immunostaining. A ntibodies from AKR(H-2K) and CBA/H (H-2k) mice reacted strongly after immunoblotting with antigens of 87 and 96 kDa. In contrast, immune ser a from both the highly susceptible DBA/2J (H-2d) mice and the resistan t BALB/c (H-2d) mice reacted strongly with an antigen of 48 kDa. C57B1 /6J (H-2b) mice produced variable antibody reactivity to antigens of 4 8, 65, 66 and 79 kDa depending on the IgG subclass tested. The IgG sub class responses and the patterns of antigen recognition in these mice suggest that humoral responses to C. albicans may be restricted by H-2 haplotype. There was no clear correlation between humoral immunity an d resistance or susceptibility to infection with C. albicans.