Cell-Mediated Immune Response to Simian Oncornavirus Antigens in Pregnant Women 2

Abstract

Tritiated thymidine Incorporation into lymphocytes of 118 adult women was studied in the presence of mitomycin C-treated cells prepared from cell lines continuously producing Mason-Pfizer monkey virus (MPMV), baboon C-particle virus, or simian sarcoma virus (SSV) and in the presence of control cell lines documented for the absence of oncornaviruses. At the end of pregnancy, women who had had 5–9 pregnancies showed a high frequency (53%) of specific positive responses to cells with MPMV antigens. The frequencies were 15% for pregnant women with smaller numbers of pregnancies and 3% for nonpregnant women with similar numbers of previous pregnancies as in the pregnancy group. None of these nonpregnant women had lymphocytes responding to stimulation by baboon C-virus antigens, but positive responses were obtained in 20 and 16% of the pregnant groups, respectively. No correlation was found between responses to MPMV or baboon C-virus antigens. Of 48 women (35 pregnant, 13 nonpregnant) who were tested for lymphocyte responses to SSV antigens, only 2 showed a positive response. The results indicated that two distinct antigens, related to MPMV and to baboon C-virus, may be expressed during pregnancy and may then induce a transient ceil-mediated response.