Pneumocystis carinii Major Surface Glycoprotein Dampens Macrophage Inflammatory Responses to Fungal β-Glucan.
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ABSTRACT: Background
Pneumocystis major surface glycoprotein (Msg) is a 120-kD surface protein complex on the organism with importance in adhesion and immune recognition. In this study, we show that Msg significantly impairs tumor necrosis factor (TNF)-α secretion by macrophages induced by Saccharomyces cerevisiae and Pneumocystis carinii (Pc) β-glucans.Methods
Major surface glycoprotein was shown to greatly reduce β-glucan-induced Dectin-1 immunoreceptor tyrosine-based activating motif (ITAM) phosphorylation. Major surface glycoprotein also down regulated Dectin-1 receptor messenger ribonucleic acid (mRNA) expression in the macrophages. It is interesting that Msg incubation with macrophages resulted in significant mRNA upregulation of both C-type lectin receptors (CLR) Mincle and MCL in Msg protein presence alone but to even greater amounts in the presence of Pc β-glucan.Results
The silencing of MCL and Mincle resulted in TNF-α secretions similar to that of macrophages treated with Pneumocystis β-glucan alone, which is suggestive of an inhibitory role for these 2 CLRs in Msg-suppressive effects on host cell immune response.Conclusions
Taken together, these data indicate that the Pneumocystis Msg surface protein complex can act to suppress host macrophage inflammatory responses to the proinflammatory β -glucan components of the organisms.
SUBMITTER: Kottom TJ
PROVIDER: S-EPMC7459132 | biostudies-literature |
REPOSITORIES: biostudies-literature
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