Effect of erythromycin treatment on specific immunologic response in mice.

Six week old Swiss mice were sensitized by subcutaneous injection of 10(7) sheep red blood cells without adjuvant. One hour after sensitization, the mice were treated with erythromycin lactobionate for ten days. The minimal (15 mg/kg/day) and maximal (57 mg/kg/day) doses clinically used were assayed. The daily dose of erythromycin was administered intraperitoneally, in two injections, one every 12 hours. The kinetics of delayed type hypersensitivity reaction, measured by means of the foot-pad test, was evaluated by challenging different groups of fourteen mice with an eliciting dose of 10(8) SRBC injected into the foot-pad on days 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 after sensitization. Total and 2-mercaptoethanol resistant haemagglutinating antibody titres were determined in sera obtained from mice immediately after measuring the delayed type hypersensitivity reaction. Treatment with maximal erythromycin dose gave rise to a significant enhancement of the cellular immune response, and also to an acceleration of the humoral antibody response. On the other hand, treatment with minimal erythromycin dose gave rise to a slight depression of the immune cellular response and also to a depression of the antibody production at the beginning of the humoral response.