Mouse fetal liver:a source of immunologically reactive cells.

Abstract

Male and female AHeJ mice were mated and the resulting pregnancies were surgically interrupted at various stages of gestation. The embryos were dissected and identical organs (liver, thymus, gut, placenta, and umbilicus) from each separate pregnancy were pooled and injected i.p. into sublethally irradiated (500 rad) F/sub 1/ hybrids (either ((BALB/c x A))F/sub 1/ or ((C57L x A))F/sub 1/ ). Death of the F/sub 1/ hybrids within 60 days was the criterion for the presence of immunologically competent cells in the inoculum. At the end of this period the survivors were sacrificed, their spleens and lymph nodes homogenized, and injected i.p. into sublethally irradiated F/sub 1/ hybrids of the other type. Again death within 60 days was the criterion for the presence of immunologically competent cells in the inoculum. One death occurred among the primary hosts. Immunologicaily competent cells were detected in secondary recipients of 2nd trimester fetal liver, 2nd trimester thymus, and 3rd trimester fetal liver. No immunologically competent cells were found in secondary recipients of 3rd trimester and newborn thymus. Deaths occurred among secondary hosts of fetal gut, umbilicus, and placenta. There were two deaths among the secondary control mice. It was concluded that 2nd and 3rd trimestermore » mouse fetal liver, 2nd trimester fetal thymus, and perhaps other fetal tissues contain potemtial immunologically competent cells. The theoretical significance of these data is discussed. (auth)« less