Nonopsonic Phagocytosis of Zymosan andMycobacterium kansasiiby CR3 (CD11b/CD18) Involves Distinct Molecular Determinants and Is or Is Not Coupled with NADPH Oxidase Activation

作者：Véronique Le Cabec, Carine Cols, Isabelle Maridonneau‐Parini · 发表于：Infection and Immunity · 年份：2000 · DOI：10.1128/iai.68.8.4736-4745.2000 · 被引用次数：123 · 研究领域：Mycobacterium research and diagnosis、Immune Cell Function and Interaction、Tuberculosis Research and Epidemiology

Complement receptor type 3 (CR3) was initially described as an opsonic receptor. Subsequently, CR3-mediated lectin-sugar recognition mechanisms have been shown to play a major role in the nonopsonic phagocytosis of several pathogens, among them Mycobacterium tuberculosis. Little is known about the binding and signal transduction mechanisms operating during nonopsonic ingestion through CR3 of different microorganisms. In the present study, we used CHO cells stably transfected with CR3 to show that CR3 was able to mediate internalization of zymosan and pathogenic mycobacteria (Mycobacterium kansasii and Mycobacterium avium) but not that of nonpathogenic species (Mycobacterium smegmatis and Mycobacterium phlei). A combination of mannan and beta-glucan inhibited the phagocytosis of zymosan but had no effect on M. kansasii ingestion. Among six monoclonal antibodies (MAbs) directed against the CD11b subunit of CR3 that decreased zymosan ingestion, only three inhibited M. kansasii phagocytosis. In particular, MAbs known to block the CR3 lectin site affected only internalization of zymosan. Using U937 macrophages, we observed that zymosan ingestion through CR3 induced superoxide production measured by cytochrome c reduction and by translocation of the NADPH oxidase cytosolic component p47phox to the phagosomal membrane, whereas phagocytosis of viable or heat-killed M. kansasii did not. Furthermore, lack of superoxide anion production during phagocytosis of M. kansasii was not due to ...