M1 macrophage induction in severely burned mice treated with CCL1 antisense ODN (111.9)

Abstract

Abstract We have reported that M2bMϕ, an inhibitor cell for M1Mϕ generation, are generated in mice 1 to 3 weeks after severe burn injury. CCL1 released from M2bMϕ acts as an autocrine signaler for keeping their suppressor cell properties. In this study, we tried to induce M1Mϕ in burned mice treated with CCL1 antisense ODN. BALB/c burned mice (25% TBSA, 3rd degree flame burn) were treated s.c. with 10 μg/mouse of CCL1 antisense ODN twice a day for 2 days beginning 13 days after burn injury. F4/80+ peritoneal Mϕ isolated from mice 12 hrs after the final treatment were tested for their M2bMϕ properties based on the expression of LIGHT mRNA and intracellular IL-10. These burned mice were then stimulated with heat-killed MRSA for M1Mϕ induction. Mϕ were considered as M1Mϕ if they expressed iNOS mRNA and intracellular IL-12. CCL1 was not detected in sera of burned mice treated with CCL1 antisense ODN. Mϕ from these mice did not express LIGHT mRNA and IL-10, while LIGHT+ IL-10+ Mϕ were isolated from burned mice treated with scrambled ODN. Further, iNOS+ IL-12+ Mϕ were induced by the bacterial antigen in burned mice subjected to the gene therapy. These results indicate that M2bMϕ are eliminated by CCL1 antisense ODN in severely burned mice, and M1Mϕ are induced in these mice stimulated with the antigen. CCL1 antisense ODN gene therapy may improve host’s antibacterial innate immunity severely suppressed in burned individuals.