Fetal cytotoxic antibodies to maternal T-lymphocytes: a possible mechanisms for maternal tolerance of the fetal allograft

Cytotoxic antibodies to lymphocytes: relationship to sperm immunity

Sperm and T lymphocytes share antigens, and sera from infertile subjects with sperm immunity have agglutinating antibodies to T lymphocytes. In the present study, cytotoxic antibody titers to sperm (C-Sp) and lymphocytes (C-Ly) were measured in sera, seminal plasma, cervical mucus and vaginal secretions of 52 infertile couples. The samples were divided into C-Sp negative and C-Sp positive groups. C-Ly titers against control T lymphocytes were significantly elevated in C-Sp positive sera of 35 males (P less than 0.005) and 27 females (P less than 0.05) as compared with C-Sp negative sera. C-Ly titers against autologous or partner T lymphocytes were similarly elevated in the sera of both groups. Titers of C-Ly in C-Sp positive secretions (seminal plasma, cervical mucus and vaginal secretions) against autologous and partner, as well as control, T lymphocytes were significantly elevated. In addition, elevated titers of C-Ly to autologous, partner and control B lymphocytes were observed in sera, cervical mucus and vaginal secretions from females with sperm immunity. The infertile males, however, did not have significant B lymphocyte immunity. Immunofluorescence assays revealed a significantly higher incidence of sperm and T lymphocyte antibodies (primarily IgG) in the C-Sp positive than in the C-Sp negative group. Titration of 100 sera from infertile subjects (50 couples) against a panel of lymphocytes of known HLA specificities failed to reveal a pattern of activity against HLA antigens of the A, B and C loci. Absorption of immune sera with sperm or lymphocytes reduced C-Sp and C-Ly titers significantly (P less than 0.001). These results suggest that infertile subjects with sperm immunity produce antibodies to cross-reactive antigens present on sperm and T lymphocytes.

Sperm immunity in infertile couples: antibody titers are higher against the husbands' sperm than to sperm from controls

Titers of hemagglutination and cytotoxic antibodies to sperm were determined in the sera, seminal plasma, cervical mucus, and vaginal secretions from 69 infertile couples, using sperm from the husbands and from normal control subjects. Titers of hemagglutination and cytotoxic antibodies were significantly higher (p = 0.002 and p less than 0.001, respectively) against autologous sperm as contrasted with sperm from control subjects in sera from 55 autoimmune males. Hemagglutination and cytotoxic antibody titers were also significantly higher (p = 0.044 and p less than 0.001, respectively) against their husbands' sperm as contrasted with control sperm in sera from 46 females with isoimmunity to sperm. Ninety percent of males and females with sperm immunity were positive for histocompatibility antigens HLA-B7, HLA-B8, and/or HLA-BW35. In males, the presence of increased serum cytotoxic antibody titers against autologous versus control sperm was significantly associated with the presence of HLA-B7 allele (p = 0.0017) and with HLA-B7, HLA-B8, and/or HLA-BW35 in general (p less than 0.05). In the females, increased serum antibody titers to their own husbands' versus control sperm were not preferentially associated with HLA-B7, HLA-B8, or HLA-BW35 antigens.