DIFERENTIAL DNA SYNTHESIS IN A nopheles albimanus TISSUES INDUCED BY IMMUNE CHALLENGE WITH DIFFERENT MICROORGANISMS

The induction of DNA synthesis in various tissues of A nopheles albimanus, in response to challenge with S accharomyces cerevisiae, M icrococcus luteus, and S erratia marcescens, was analyzed by 5‐bromo‐2‐deoxy‐uridine ( B rd U ) incorporation. Microorganism‐inoculated mosquitoes were fed with a sucrose solution containing B rd U and maintained alive for 5 days. Alternatively, abdominal carcasses of microorganisms‐inoculated mosquitoes were cultivated in R oswell P ark M emorial I nstitute ( RPMI ) medium supplemented with B rd U for 5 days. Control groups were inoculated with RPMI alone. In both experiments, DNA synthesis, evidenced by epifluorescence with an anti‐ B rd U fluorescein‐labeled antibody, occurred in fat body, epithelial cells of pleural membranes, dorsal vessel, and the oviducts. Relative quantification of DNA synthesis, evaluated by ELISA using an anti‐ B rd U peroxidase‐labeled antibody, was higher in abdomen tissues of microorganisms‐inoculated mosquitoes than controls in in vitro and in vivo experiments. The intensity of DNA synthesis varied among the different microorganism challenges, but was higher in in vivo experiments, compared to cultured samples. These differences in DNA synthesis suggest a compartmentalization of the immune response, probably mediated by different signaling pathways.