THE EFFECTS OF MONOCLONAL-ANTIBODIES AGAINST IC3B RECEPTORS IN MICE WITH EXPERIMENTALLY-INDUCED DISSEMINATED CANDIDIASIS

CR3 (iC3b receptor), composed of CD11b/CD18, is a beta(2) integrin. A protein that shares antigenic and structural homology with the alpha-c hain of CD11b/CD18 has been isolated from the surface of Candida albic ans. This molecule is thought to be essential in the pathogenesis of d isseminated candidiasis. To evaluate the effects of anti-iC3b receptor antibodies on adhesion between human dermal microvascular endothelial cells (HDMEC) and C. albicans, and in treatment of candidal infection , a binding assay of C. albicans to cultured HDMEC was performed in vi tro. An anti-iC3b receptor-specific monoclonal antibody was administer ed to mice infected with C. albicans. The mice were monitored for mort ality and renal involvement by culture and histopathological findings. Flow cytometric analysis demonstrated surface expression of iC3b rece ptor on C. albicans. The adherence of C. albicans to HDMEC was signifi cantly decreased by treatment with anti-iC3b receptor antibodies. Anti -iC3b receptor antibodies significantly increased the survival time an d rate while lowering the renal fungal burden. The iC3b receptors are involved in the adherence of C. albicans to vascular endothelial cells and are likely to be involved in the pathogenesis of disseminated can didiasis. The increased survival in mice infected with C. albicans aft er treatment with anti-iC3b receptor antibodies indicates that this mo dality may be beneficial for future development of a new therapy for c andidiasis.