RESUMO
Severe suppression of the immune system is the major cause of infections following burn injury. The aim of this study was to investigate the time-related alterations of immune responses following thermal injury in an animal model and also to modulate immune responses by use of the immunomdulators cimetidine and pyrimethamine. Male Balb/c mice were anesthetized and given a 10% total body surface area full-thickness burn. The timedependent changes of delayed type hypersensitivity [DTH] and antibody responses to sheep red blood cell [SRBC] were assessed at post-burn days [PBD]. The effects of different doses of cimetidine and pyrimethamine on DTH response were also quantitated at 10 PBD. Marked suppression of DTH response occurred during 30 days after burn trauma, with maximal suppression occurring between 10 to 14 days after burn injury. Simultaneously the antibody response to SRBC was significantly increased after thermal trauma. Cimetidine [at doses of 10 and 15 mg/kg] and pyrimethamine [at doses of 5 and 10 mg/kg] significantly augmented DTH response after thermal injury. These results showed that the severe time-dependent alterations occurred in DTH and antibody responses following burn injury. Cimetidine and pyrimethamine also restore burn-induced suppression of DTH response following thermal trauma