Lymphocyte stimulation by allogeneic cells in sperm-free ejaculates

HLA-D determinants are expressed on human seminal cells other than spermatozoa but not on purified spermatozoa

Purified human spermatozoa do not regularly stimulate lymphocytes in spermlymphocyte cultures (SLC). This lack of consistent stimulation was found not to be dependent on sperm/lymphocyte ratio or on culture peak response time. A few weak stimulations obtained are not HLA-D or sex dependent. Contaminating seminal cells other than spermatozoa (SC non-SZ) may be responsible for the high stimulations found in SLC by others, since, in our hands, purified suspensions of SC non-SZ stimulate allogeneic lymphocytes in an HLA-D-dependent fashion, and such responses are abrogated by anti-HLA-DR monoclonal antibodies. These functional data confirm our previous finding of HLA-DR molecules on SC non-SZ by absorptions (and a lack of expression on spermatozoa) and suggest the concomitant expression of HLA-DQ and -DP products.

Production of interferon gamma by lymphocytes exposed to antibody-coated spermatozoa: a mechanism for sperm antibody production in females

The ability of sperm to induce lymphocytes from female donors to produce interferon gamma (IFN) was measured. Of nine samples where immunoglobulin was bound to ejaculated motile sperm, five (55.6%) induced IFN production. In contrast, only 1 of 35 (2.9%) sperm samples lacking bound immunoglobulins induced IFN (P less than 0.005). Incubation of donor sperm with sperm antibody containing sera from nine male patients led, in seven cases (77.8%), to acquisition by sperm of the ability to induce IFN. Lymphocytes from eight of eight females tested all responded to sperm with bound antibodies. IFN induction of Ia antigen expression on macrophage may be required for recognition of processed sperm antigens by the female's T helper cells.

Human leukocyte antigens (HLA) class I and class II on sperm cells studied at the serological, cellular, and genomic levels

The expression of human leukocyte antigens (HLA) on highly purified human ejaculated sperm cells was studied using the sensitive enzyme-linked immunosorbent assay (ELISA) technique and a wide panel of monoclonal antibodies to class I and class II HLA. In addition, the stimulatory capacity of these cells was tested in mixed cultures of lymphocytes and spermatozoa, and the levels of RNA homologous to the HLA class I and class II genes were determined. The results obtained using the ELISA indicate that the class I and class II HLA serologically defined antigens are weakly expressed on the cell surface of the mature spermatozoa. Highly purified sperm cells consistently stimulated heterologous lymphocytes but not when HLA-DR compatibility was observed between stimulator and responder. The proliferative response of lymphocytes induced by sperm cells was lower than the response obtained in a lymphocyte-lymphocyte combination, though the kinetics of the response were similar in both cases. In addition, it was found that spermatozoa contained RNA species homologous to HLA class II DR beta and DQ beta genes sequences but not to HLA class I sequences. The levels of these RNA species were significantly reduced after interferon stimulation. Lymphocytes that served as positive control were found to contain RNA complementary to both HLA class I and class II genes.