Investigating Host and Environmental Influences of Fusarium solani Using a Novel Monoclonal Antibody

Human fungal infections among severely immunocompromised individuals have increased dramatically over the last 30 years and that coincidence with an expanding patient numbers of bone marrow and solid organ transplantation and those receiving aggressive cytotoxic chemotherapy for neoplastic diseases or immunosuppressive drugs. In recent years, many of opportunistic fungi have emerged as serious human pathogens and causing life-threatening infections of humans such as Fusarium species. Due to lack of a highly accurate diagnostic test for tracking the pathogenic Fusarium species, fusariosis is frequently misdiagnosed as aspergillosis. Delays in identification and differentiation of Fusarium spp. from other causative agents of hyalohyphomycetes associated with high morbidity and mortality rate among immunocompromised patients. This research aimed to develop a highly specific monoclonal antibody (mAb) using hybridoma technology to produce a highly genus-specific murine mAb ED7 that could be used for tracking and early detecting circulating Fusarium species antigens from other opportunistic pathogens. At present, a very little is known about the pathogenicity and interaction of human pathogenic F. solani and cells of the innate immune system like alveolar macrophages (AMØ), the residential innate immune cells of alveoli. For this reason, F. solani was genetically transformed with GFP gene and a model of immunoassay was developed to investigate the interactions of F. solani with AMØ that would allow studying the fungal pathogenicity, visualising and quantification of the pathogen during the process of macrophage phagocytosis. In addition, this model can be used to evaluate the effect of a mAb on fungal uptake by AMØ. Habitates providing direct human exposure to infectious propargules are largely unknown, but there is growing evidence that plumbing systems are sources of human pathogenic strains in the F. solani and F. oxysporum species complexes, the most common groups infecting humans. Using mAb ED7 specific to the Fusarium species, this work demonstrates how the mAb can be used as a powerful immunodiagnostic tool for accurately tracking the Fusarium species antigens in sink drain biofilms and water system samples containing mixed populations of human opportunistic filamentous and yeasts pathogenic fungi across a University campus and a tertiary care hospital. Specificity of the ELISA was confirmed by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2 rRNA-encoding regions of culturable yeasts and moulds that were recovered using mycological culture, while translation elongation factor (TEF)-1 analysis of Fusarium isolates included FSSC 1-a, FOSC 33 and FDSC ET-gr, the most common clinical pathotypes in each group. The mAb ED7 is, therefore, suitable to be carried forward for use in diagnostic assays, such as the lateral flow device