Aspergillus fumigatus proteins bound by a germination inhibitory monclonal antibody

Abstract

Aspergillus fumigatus, a common fungus, causes several forms of disease in humans. One such disease, invasive aspergillosis (IA), has a very high mortality rate in the immunosuppressed population. Dr. Marta Feldmesser and the Albert Einstein College of Medicine Hybridoma Facility synthesized a monoclonal antibody (MAb 318) that binds to the fungal spores and prevents germination. Administration of this MAb prolongs survival in experimentally infected mice. Three fungal proteins, an aldehyde dehydrogenase, catalase (Catl), and an actin cortical patch component, were previously identified as binding MAb 318. The interaction(s) responsible for inhibition of germination is not known. The goal of this study is to make recombinant proteins of actin cortical patch component and aldehyde dehydrogenase to confirm the identity of the targets. Parallel processes for the preparation of the two recombinant proteins were performed. RNA was isolated from sporulating cultures for synthesis of cDNA. The genes were amplified using PCR. We digested the PCR products and ligated them into the plasmid pGAPZA. The plasmid was then electroporated into Pichia pastoris. We are currently assessing protein production in this expression system by Western blot and ELISA. Our research hopefully will confirm that MAb 318 binds one or more of the identified proteins. These proteins can be used to synthesize protein-specific antibodies and may be used to develop a vaccine against IA.