Identification of a Novel Variant Form of Aspergillus fumigatus CalC and Generation of Anti-CalC Monoclonal Antibodies.

ABSTRACT

Aspergillus fumigatus is a critical human fungal pathogen that infects the host via inhalation of airborne conidia. These conidia then germinate to form filamentous hyphae, which secrete various elements to survive in the host lung.Elements such as proteins secreted by A. fumigatus can act as virulence factors in host tissues. Among secreted proteins, we were interested in the thaumatin-like proteins of A. fumigatus. In our analysis of the function of thaumatin-like proteins, we found that, like CalA and CalB, CalC has a secreted form. Originally, CalC was predicted to be a GPI-anchored protein, as documented in the Aspergillus Genome Database. Here, we report on a novel secreted form of CalC. Furthermore, we established two novel hybridomas, C103 and C306, which recognized CalC. Monoclonal antibodies produced by these hybridomas responded to recombinant CalC produced by the mammalian cell line HEK293T and to the supernatant of cultured A. fumigatus.Taken together, our data suggest that calC can be spliced to give rise to a novel secretory form of CalC, which is present in the supernatant of cultured A. fumigatus. The hybridomas that we established will be helpful in understanding the biological role of A. fumigatus CalC.