Isolation of chicken eosinophils and their migration response in chick embryos

Almost pure eosinophils have been isolated from chicken bursa, spleen, thymus or blood using Ficoll metrizoate and Ficoll gradient (eosinophil p.c. 71.4-87.6). Centrifugation by Ficoll discontinuous gradient yielded clear cut interface layer and had no deleterious influence on eosinophil viability. Purified eosinophil populations were examined for eosinophil migration response in vitro by exposure of the eosinophil population to lymphocytes sensitized in ovo with dinitrophenylated bovine serum albumin (DNP-BSA), DNP or BSA. Embryonic lymphocytes sensitized with antigens used led a eosinophil migration in vitro. From these findings, it is suggested that immunological maturation of the lymphocytes in the production of chemotactic factor may occur during the developing stage of chick embryos by antigenic stimulation.