Genera Curvularia and Bipolaris include closely related melanin producing filamentous fungi but while Bipolaris species infect only plants, there are opportunistic human pathogenes among Curvularia species, such as C lunata, C. spicifera or C. hawaiiensis. Infections caused by these species can manifest as local infections (e.g. keratitis, sinusitis and cutaneous lesions) in immunocompetent or invasive mycoses with frequent involvement of the central nervous system in immunocompromised patients. However, there is only little information available about the host response to these fungi. The aim of this study was to investigate the neutrophil granulocytes’ response and killing efficiency to hyphal forms of Curvularia and Bipolaris in comparison with that to the well-characterized Aspergillus fumigatus.
In the present study, C. lunata SZMC 23759 and A. fumigatus SZMC 23245, both isolated from human eye infection, and B. zeicola BRIP 19582b isolated from plant leaf were examined. Release of H2O2 from neutrophil granulocites were measured in the presence and the absence of the supernatant of germinating conidia and after serum treatment. Activation and survival of neutrophils were checked by measuring the myeloperoxidase and LDH release, respectively.
ROS production of neutrophils in interaction with the three fungi were compared. It is already known that Aspergillus species induce ROS production of neutrophils only after serum treatment. Similarly, C. lunata and B. zeicola were also able to induce H2O2 release only after serum opsonisation. Viability of C. lunata and B. zeicola did not decrease when H2O2 production was detected. A potential defence mechanism of the fungi is the neutralization of H2O2, so relative transcription level of haloperoxidase genes of C. lunata were measured after induction with H2O2.
This research was supported by the grants „Lendület” LP2016-8/2016 and GINOP-2.3.2-15-2016-00035. EJT was granted by the UNKP-17-3 New National Excellence Program of the Ministry of Human Capacities.

Response of neutrophil granulocytes to Curvularia lunata and Bipolaris zeicola