IMMUNOPROTECTION AGAINST SYSTEMIC CANDIDIASIS IN MICE

We have previously described an immunosuppressive a cell mitogenic (IS M) protein, p43, produced by Candida albicans, which plays an importan t role in the survival of the microorganism in the host, The N-termina l amino acid sequence of p43 was found to be different from all amino acid sequences registered in updated protein databanks, Immunization o f BALB/c mice with p43 partially neutralized the biological effects of this protein, namely depletion of bone marrow pre-B and a cells, the increased numbers of total and large a and CD4(+) lymphocytes, and the non-specific polyclonal response of splenic IgG2a-, IgG2b- and IgM-se creting plaque forming cells, Immunization of BALB/c mice with p43 ful ly protected the mice against the fungal infection. In contrast, immun ization with C. albicans sonicates (Cs) was not protective, Our data i ndicated that specific antibodies against p43 protected, whereas those against Cs facilitated C. albicans infection, Thus, the ratio between anti-p43 and anti-Cs antibody titres was much lower in the non-protec ted mice (Cs-immunized and control non-immunized) than in p43-immunize d mice, Moreover, passive administration of specific anti-p43 antibodi es significantly protected against fungal infection, whereas passive a dministration of specific anti-Cs antibodies markedly increased the su sceptibility to C. albicans infection, These observations are discusse d on the basis of alternative approaches of immunointervention.