LDL acts as an opsonin enhancing the phagocytosis of group A Streptococcus by monocyte and whole human blood

• DOI: 10.1007/s00430-015-0436-8
• Publication Date: 2015-09-21T04:26:56Z
• Authors: Lulei Zhou; Ling Liu; Jinli Yang; Yuxin Li; Wencheng Bai; Na Liu; Wenlong Li; Yumin Gao; Liping Xu; Zhi Liu; Runlin Han
• Keywords: Scavenger Receptor; CD36; Monocyte; Antibody opsonization; Low-density lipoprotein

Low-density lipoprotein (LDL) binds to group A Streptococcus (GAS) through Sc11 protein, and scavenger receptor CD36 of monocyte mediates the endocytosis native or modified LDL. Therefore, we hypothesized that LDL might be an opsonin enhancing phagocytosis LDL-bound GAS by monocyte. The results showed could significantly promote U937 cell phagocytose M28 (ATCC BAA1064) M41 12373, AM41)-type GAS, rates were increased, compared with LDL-free group. LDL, however, did not enhance (CMCC 32198, CM41) M6 BAA946)-type since these two strains bind was major mediating uptake cells anti-CD36 antibody abolished LDL-opsonized but anti-CD4 not. Most AM41-type killed in human blood, whereas only a few CM41-type phagocytosed. Moreover, recombinant Scl1 (rScl1) derived from M41-type decrease opsonophagocytosis AM41 because rScl1 competitively blocked binding our findings suggest may CD36-dependent opsonic