The role of acrosomal enzymes in lymphocytes stimulation by spermatozoa

Major histocompatibility complex expression on human, male germ cells: a review

PROBLEM

The male reproductive compartment is an immunologically privileged site. The expression pattern of human leukocyte antigens (HLAs) may play an important role in the maintenance of immune tolerance toward differentiating gametogenic cells. This review presents current knowledge about HLA gene expression on human, male germ cells, on mRNA and protein levels, and on their methylation status.

METHOD OF STUDY

Different techniques were applied to study HLA gene expression in human testis: (a) protein: e.g., cytotoxicity test, fluorescent labeling techniques, enzyme-linked immunosorbent assay, and confocal microscopy; (b) mRNA: reverse transcriptase-polymerase chain reaction, Northern blot hybridization, and in situ hybridization; and (c) methylation status.

RESULTS

In normal testicular tissue we observe a lack of HLA-class I (classical) antigens expression and inversely related expression pattern of HLA class I classical and nonclassical genes. HLA-A, -B, -C, and -E loci are likewise methylated in somatic and germ cells, whereas -F and -G genes are less methylated in sperm precursors.

CONCLUSIONS

Immunologic tolerance in human testis is actively maintained by the specific expression pattern of HLA genes regulated by hormones and growth factors.

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.