Reprints
PubMed
CAVEAT LECTOR
Section of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190
In the past five years, our knowledge of sperm-oocyte interaction has increased considerably. Sperm-oolemma adhesion and fusion appear to be the result of coordinated expression of several of cell adhesion molecules. The sperm-oocyte adhesion appears to be initiated primarily by the ß1-integrin cell adhesion molecules. Whereas, sperm-leukocyte recognition and sperm entry is initiated by the binding of ß2-integrin protein, CR3, to antisperm antibody and C-coated motile sperm. On the other hand, the entry of sperm into non-phagocytic cells and genital tract epithelial cells is non-integrin mediated. Reproductive biologists are now faced with the challenge to further unravel the relevant molecules involved in sperm membrane-oolemma adhesion and fusion. Availability of antibody probes to generate a variety of human gamete-specific recombinant proteins and the use of human IVF systems to assess their function would certainly help to unravel the molecular events that lead to human physiological fertilization. Identification of a subset of patients with specific defects at the level of sperm membrane-oolemma interaction will be quite useful in further delineating the functional significance of these adhesion molecules. This rapidly moving area of reproductive biology may provide us with important tools for contraception. Alterations of receptor/counter-receptors on gametes, leading to a delay or prevention of binding, fusion and/or oocyte activation is one possible approach for reversible contraception. Moreover, qualitative molecular changes affecting the adhesion of sperm membrane-oolemma can be used as a basis for intervention in fertilization. In principle, it should be possible to inhibit sperm-oocyte interaction by inducing antibodies to the unique adhesive receptors or by peptides reproducing integrin binding sites of sperm or the active site of putative oocyte integrin. Inhibition of fertilization at the level of sperm-oocyte fusion has been documented in the presence of auto or iso ASA and mAbs specific to sperm head antigens.