关键词: Candida albicans, CARD9, 中性粒细胞, ROS, 吞噬, 吞噬溶酶体, 白细胞介素-8

Abstract: Caspase recruitment domain-containing protein 9 (CARD9) is an adaptor molecule that is critical for NF-κB activation,and forms a complex with B-cell lymphoma 10 (BCL10) and mucosa-associated lymphoid tissue lymphoma translocation gene 1 (MALT1) that mediates C-type lectin receptors (CLRs)-triggered intracellular signaling during antifungal immunity.In the present study,we investigated the functions of polymorphonuclear neutrophils (PMNs) from phaeohyphomycosis patients with CARD9 deficiencies against Candida albicans (C.albicans).PMNs were isolated from patients and healthy blood donors and subsequently challenged with C.albicans.By calculating colony-forming units and MTT assay,the killing of C.albicans by CARD9-deficient neutrophils was detected,and the ROS production and phagocytotic ability of CARD9-deficient neutrophils was assayed by Flow CytoMetry (FCM).The phagolysosome ultrastructure and the secretion of IL-8 were analyzed separately by EM and CBA kit.As a result,we demonstrated that,compared with healthy donors,CARD9-deficient PMNs exhibited defects in C.albicans killing and IL-8 productions,which can be rescued in the presence of serum;however,the CARD9-deficient PMNs exhibited normal reactive oxygen species generation,phagocytotic ability and phagolysosome ultrastructure.In conclusion,our results indicate that CARD9 is indispensable for C.albicans killing by PMNs,and serum-opsonization acts as a CARD9-independent way,which could be a promising immunotherapy in the future.

Key words: Candida albicans, CARD9, Neutrophils, ROS, Phagocytosis, Phagolysosome, IL-8