Immune responsiveness of a novel peptidoglycan conjugate prepared from surface Candida immunogens: mannan and CR3-related protein.

Candida albicans expresses a CR3-related protein (CR3-RP) antigenically, structurally and functionally related to human adhesion glycoprotein, also known as Mac-l, the iC3b receptor, or complement receptor type 3. The purpose of the present study was to analyze the immunogenic properties of a novel CR3-RP glycoconjugate in a rabbit model. Cell-mediated responses revealed immunoenhancement triggered by CR3-RP glycoconjugate with respect to expression of IL-2 receptor subunit CD25 on B-lymphocytes and inductive increase of the CD4(+)/CD8(+) ratio compared with unconjugated cell wall mannan (P<0.001). Active immunization with the CR3-RP glycoconjugate resulted in an effective IgM-IgG isotypic switch even after the second booster. Altogether, it could be assumed that the novel peptide glycoconjugate is a prospective antigenic candidate for further Candida vaccine design.