BURN INJURY INDUCES A BIPHASIC IMMUNOGLOBULIN-M RESPONSE TO BACTERIAL-ANTIGEN

We studied 75 BALB/c mice to examine the role of impaired imunnoglobul in M (IgM) synthesis in the increased risk of bacterial infection afte r burn injury by investigating the kinetics of IgM synthesis to peptid oglycan polysaccharide (PGPS), a ubiquitous bacterial antigen. Splenoc ytes were isolated 1, 5, and 8 days postburn (PBD) and cultured with l ipopolysaccharide for 5 days. Culture supernatant was collected and an ti-PGPS IgM and total IgM levels were measured by ELISA. Total IgM-sec reting cells were measured by ELISPOT assay. Total IgM and anti-PGPS I gM per IgM-secreting cell were calculated. On PBD 1, anti-PGPS IgM syn thesis but not total IgM synthesis is increased in burned animals. By PBD 5, total IgM and anti-PGPS IgM synthesis in the burn group start t o fall and by PBD 8, both are significantly decreased. The early incre ase in anti-PGPS IgM synthesis represents a positive response to bacte rial challenge. However, the late nonspecific decrease in total IgM an d anti-POPS IgM synthesis suggests a potential mechanism for increased susceptibility to bacterial infection 5 to 10 days after burn injury.