Adoptive immune responses of chicken immunocytes in embryonic and neonatal hosts

The adoptive immune capacities of peripheral blood immunocytes from unprimed juvenile B haplotype-matched donors were compared in late embryonic and neonatal chick hosts. Adoptive PFC counts of immunocytes that responded to mouse erythrocytes (MER+) were high in late embryo and newly hatched chick hosts but somewhat less in older neonatal hosts. In contrast, the PFC levels of immunocytes that responded to sheep erythrocytes (SER+) were high in late embryo and older neonatal hosts, but conspicuously depressed in newly hatched chick hosts. The addition of spleen cells from neonatal 4- to 7-day chick donors to the donor cell inoculum appeared to enhance the adoptive immune responses of MER+ cells in embryonic hosts.