Enlargement and immune activity of chick embryo host spleen associated with transfer of B-haplotype-matched donor lymphoid cells.

Splenic enlargement was elicited in embryo hosts with the transfer of blood leukocytes, spleen cells, thymocytes, and bone marrow cells from B-haplotype-matched donors. The splenic growth profile of embryos grafted with B-haplotype-compatible donor cells, although elevated, was more like that of control embryos than hosts undergoing a graft-versus-host reaction (GVHR). The spleens of compatible hosts, moreover, lacked the obvious signs of GVHR incompatibility. Even greater splenic enlargement and splenic formation of plaque-forming cells (PFCs) was associated with the transfer of blood leukocytes and spleen cells from mouse RBC-primed donor birds, but not with bone marrow or thymus cells. The residual splenic enlargement not attributable to the proliferation and maturation of PFC precursors is believed to be the consequence of the colonization and growth in the host spleen of other hemopoietic precursor cells in the cell suspensions.