Bursa lymphocytes and IgM-containing cells in chicken embryos bursectomized at 52-64 hours of incubation

A technique of surgical removal of the bursal primordium ("bursectomy") of chicken embryos at stage 17, approximately 52-64 hours and 29-32 somites, is described. The survival rate of bursectomized (Bx) embryos approached a level of 50% on the 21st day. About 20% of correctly Bx embryos exhibited malformations of the anal sphincter and the large intestine. Using a rabbit anti-bursacyte serum, which did not react with thymocytes, the specific bursa-derived cell (Bu) marker was detected on the surface of bursa, spleen, bone marrow and thymus lymphocytes. Early embryonic bursectomy caused a moderate depletion of Bu marker-bearing and IgM-containing cells. It has been postulated that embryonic Bu cells can be recruited from sites other than the bursa and in the absence of the bursa.