Immunotoxic action of cyclosporin A on the humoral immune response of Galleria mellonella pupae

Abstract

Cyclosporin A (CsA) was inoculated into the hemocel of pupae in the initial phase of the immune response (at the time of immunization) and in the effector phase of the immune response (within 18 h post immunization). The results obtained indicate suppression of the humoral immune response of pupae after treatment with the antibiotic CsA in both the initial and the efector phase. The immunosuppressant decreased the lysozyme activity against Micrococcus luteus and the activity of antibacterial peptides against Escherichia coli in the hemolymph within 3 days after injection. The peptide activity decreased more rapidly in comparison to the activity of lysozyme. After 72 h incubation, the reduction in the lysozyme activity was about 55 % in comparison to the activity in immunized insects and only traces of activity against E. coli were observed. Differences between the untreated and immunosuppressant-treated insects were statistically significant. The decrease in the lysozyme activity and the antibacterial peptide activity was correlated with loss of protective immunity against Pseudomonas aeruginosa.