In:
Scientific Reports, Springer Science and Business Media LLC, Vol. 6, No. 1 ( 2016-05-16)
Abstract:
Clearance of apoptotic cells by macrophages plays an important role in maintaining tissue homeostasis. Previous study indicated that streptococcal pyrogenic exotoxin B (SPE B) reduces phagocytic activity in group A streptococcus (GAS) infection. Here, we demonstrate that SPE B causes an inhibitory effect on protein S-mediated phagocytosis. In the presence of SPE B, serum- and purified protein S-mediated phagocytosis of apoptotic cells were significantly inhibited. The binding abilities of protein S to apoptotic cells were decreased by treatment with SPE B. Bacterial culture supernatants from GAS NZ131 strain also caused a reduction of protein S binding to apoptotic cells, but speB mutant strain did not. SPE B directly cleaved protein S in vitro and in vivo , whereas a lower level of cleavage occurred in mice infected with a speB isogenic mutant strain. SPE B-mediated initial cleavage of protein S caused a disruption of phagocytosis and also resulted in a loss of binding ability of protein S-associated C4b-binding protein to apoptotic cells. Taken together, these results suggest a novel pathogenic role of SPE B that initiates protein S degradation followed by the inhibition of apoptotic cell clearance by macrophages.
Type of Medium:
Online Resource
ISSN:
2045-2322
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2016
detail.hit.zdb_id:
2615211-3