Cell transplantation into immunodeficient chicken embryos Reconstituting capacity of cells from the bursa of fabricius spleen, bone marrow, thymus, and liver of 18-day-old embryos

Abstract

Cyclophosphamide-treated 18-day-old chicken embryos were transplanted with cells from the bursa of Fabricius, spleen, bone marrow, thymus, or liver of histocompatible embryos of the same age. To evaluate the reconstitution capacity of transplanted cells, several parameters were used to study the recipients at the age of 36 days. These parameters include survival pattern, gain of body weight, antibody-forming capacity, response of peripheral blood lymphocytes to phytohemagglutinin and concanavalin A, weight and microscopic morphology of the bursa of Fabricius, and weight of the spleen and thymus. According to all criteria employed, bursa cells were the only cells capable of a functional and morphological reconstitution of the recipient's humoral immune system. Cells from embryonic spleen, bone marrow, thymus, or liver had no reconstituting effect, indicating that these organs do not harbor precursors for the B-cell line at this stage of development. Taken together with previous observations, these findings reveal that, as a differentiation site of the B-cell lineage, the bursa of Fabricius precedes bone marrow during the ontogenetic development.