Cell and antibody mediated immunity induced by vaccination with novel Candida dubliniensis mannan immunogenic conjugate

Antigen-specific humoral response, as well as the induction of cellular immunity generated by Candida dubliniensis mannan–human serum albumin (HSA) conjugate, a novel proposed immunogenic structure for subcellular vaccine, were evaluated in rabbits. Mannan–HSA conjugate-induced specific IgG and IgA increased significantly after boosters (IgG: P < 0.001 and IgA: P < 0.01). Mannan–HSA conjugate up-regulation of cell-surface expression of B-lymphocyte and granulocyte activation antigens CD25 and CD11b indicated the effective activation. Immunogenic effect of conjugate on T lymphocytes was demonstrated via inductive increase of CD4+ T lymphocyte subset and CD4+/CD8+ ratio and via induction of TH1 cytokines. Immunogenic effectiveness of mannan–HSA conjugate at a dose of 0.25 mg of mannan antigenic moiety overcame that of the mannan alone and of yeast whole cells, thus promising further application in Candida vaccine development.