EXPANDED COHORTS OF MATERNAL CD8(-CELLS SPECIFIC FOR PATERNAL MHC CLASS-I ACCUMULATE DURING PREGNANCY() T)

A recombinant H-2K(b) transgene, GK, containing the human HLA-G gene p romoter is expressed throughout the trophoblast when inherited paterna lly, Male GK transgenic mice were mated with female T-cell receptor (T CR) transgenic mice to assess the effect of fetal H-2Kb expression on maternal H-2K(b)-specific CD8(+) T-cells during pregnancy. The number of maternal H-2K(b)-specific CD8(+) T-cells in spleen increased signif icantly (similar to 3-fold) 10 days post coitus when the GK transgene was inherited from the father. A smaller (similar to 2-fold) increase was observed in the spleen of pregnant females mated with C57BL/10 (H- 2(b)) males. No increase was observed in mothers mated to syngeneic ma le mice. In both cases where expanded cohorts of maternal CD8(+) T-cel ls were observed the amount of surface CD8 and to a lesser extent, TCR molecules was reduced. No change in the amount of surface CD44 or CD4 5RB was detected when levels were compared with naive T-cells from con trol virgin female mice. Expanded cohorts of CD8(+) T-cells were also detected in pars-aortic and inguinal lymph nodes draining the uterus b ut no changes were observed in mesenteric lymph nodes. This study conc ludes that maternal CD8(+) T-cells are exposed to paternally inherited fetal MHC class I antigens during pregnancy. Moreover, the phenotype of the CD8(+) T-cells in maternal spleen and lymph nodes that drain th e uterus is not typical of activated, antigen-experienced T-cells sugg esting that contact with fetal H-2K(b) molecules induces a state of fu nctional unresponsiveness. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.