Abstract
Allogeneic immunocompetent T cells injected into chicken embryos induce a graft-versushost
reaction (GVHR) whose most prominent manifestation is splenic hyperplasia. The
highly inbred CC and CB strains of chickens used here are, respectively, homozygous for
the B4 or B12 MHC haplotypes. By means of a panel of immunological reagents, including
alloantisera and monoclonal antibodies against public domains of the T-cell receptor, CD4,
CD8, and the inducible interleukin-2-receptor light chain (CD25), it is shown that the bulk
of cells in the enlarged spleen are of host origin and do not express markers typical of
mature T or B lymphocytes. Among recipient splenocytes, the quantitatively most important
population consists of TCR