RESUMO
Candida albicans (C. albicans) is an important human commensal and opportunistic fungal pathogen. Secreted aspartyl proteinases (Saps) are a major virulence trait of C. albicans, and among these proteases Sap2 has the highest expression levels. It is possible that antibodies against Sap2 could provide an antifungal effect. In this study, two phages displaying anti-rSap2 single chain variable fragments (scFvs) were screened from human single fold scFv libraries, and their potential therapeutic roles were evaluated using a murine model infected by C. albicans. The in vivo efficacies were assessed by mortality rates, fungal burden and histological examination. Overall survival rates were significantly increased while the colony counts and infectious foci were significantly decreased after treatment with the scFv-phages relative to the control groups. In order to investigate the immune response provoked by scFv-phages, three kinds of cytokines (Th1, Th2 and Th17 types) were measured and a clear immune response was observed. These findings suggest that anti-rSap2 scFv-phages have potential in the therapy of systemic infection caused by C. albicans.
Assuntos
Anticorpos Antifúngicos/farmacologia , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Candida albicans/imunologia , Candidíase/tratamento farmacológico , Proteínas Fúngicas/antagonistas & inibidores , Anticorpos de Domínio Único/farmacologia , Animais , Anticorpos Antifúngicos/química , Anticorpos Antifúngicos/genética , Anticorpos Antifúngicos/imunologia , Ácido Aspártico Endopeptidases/imunologia , Bacteriófago M13 , Candidíase/genética , Candidíase/imunologia , Candidíase/patologia , Modelos Animais de Doenças , Feminino , Proteínas Fúngicas/imunologia , Humanos , Camundongos Endogâmicos BALB C , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/genética , Anticorpos de Domínio Único/imunologia , ômega-CloroacetofenonaRESUMO
Historically, the therapy of serious fungal infection has been dominated by monotherapy with the polyene antibiotic amphotericin B. Clinical failures, side effects, the lack of alternatives and the toxicity of this drug have heightened the need to produce alternative therapies, which have included fluconazole, voriconazole and caspofungin. The observation that recovery from disseminated candidiasis was associated with an antibody response to the 47 kDa Candida heat-shock protein (HSP)90 homologue, coupled with the ability to sequence all the antibodies from patients who have recovered from the infection and to re-express the dominant ones as fragments in Escherichia coli, has opened the possibility of immunotherapy. The first recombinant antibody fragment, Mycograb (Neu Tec Pharma plc), against Candida HSP90 is now in clinical trials in patients with disseminated candidiasis in Europe and the US. Laboratory and early clinical data support the concept of synergy between Mycograb and amphotericin B. This should improve outcome and diminish the risk of resistance occurring to either drug, without an increase in toxicity, as this should be minimal in a human antibody fragment representing the natural antibody that a patient produces on recovery.