Monoclonal antibodies to bovine and human acrosin

Abstract

Monoclonal antibodies to human acrosin were required for studies of immunological interference with fertilization. Since human acrosin was not available in adequate amounts, monoclonal antibodies have been raised in mice against purified bovine acrosin and screened for cross-reaction with human sperm cells. Two of these antibodies are described, B4F6 and C2E5. Data from enzyme-linked immunosorbent assays, immunoblots, immunoprecipitation, and indirect immunofluorescence on sperm cells indicate that B4F6 binds only to bovine acrosin, and that C2E5 binds both to bovine and to human acrosin at a conformationally determined epitope. The antibodies do not inhibit the hydrolysis of benzoylarginine ethyl ester by acrosin, but C2E5 did inhibit the dissolution of the hamster zona pellucida by purified human acrosin. The antibodies have also been used for affinity purification of acrosin and proacrosin.

Antiacrosin antibodies and infertility. II. Gene immunization with human proacrosin to assess the effect of immunity toward proacrosin/acrosin upon protein activities and animal fertility

“…This design was chosen considering findings elsewhere showing the inhibitory effect of anti-boar acrosin antibodies when added to the gamete incubation medium but not during sperm capacitation (83,84). The results showing a significant inhibition of mouse IVF by the addition of antiacrosin antibodies raised by GI are in agreement with a report elsewhere using 630 mg/mL of a polyclonal antibody to a synthetic peptide of h-proacrosin (amino acids 43-60) (39).…”

Acrosin antibodies and infertility. I. Detection of antibodies towards proacrosin/acrosin in women consulting for infertility and evaluation of their effects upon the sperm protease activities

“…Numerous reports have documented the involvement of the proacrosin/acrosin system in mammalian fertilization in humans as well as in animal models (41)(42)(43)(44)(45), and there are some studies that have demonstrated the ability of proacrosin/acrosin to trigger an immune response (44,(47)(48)(49)(50). On the other hand, several publications have described the ability of circulating ASA to block fertilization by affecting sperm protein functions involved in this process (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21).…”

“…In addition, it was previously suggested that proacrosin/acrosin would participate in sperm-zona pellucida (ZP) binding by interaction with ZP glycoproteins (36,(42)(43)(44)(45), and the mature enzyme would help sperm penetration by limited and specific proteolysis of ZP glycoproteins (34), although the latter role is currently under revision (46). Specific antibodies to human proacrosin/acrosin have been developed in animal models (44,47,48), demonstrating the ability of this protein system to trigger an immune response. Moreover, in vivo (49,50) and in vitro (51,52) studies have demonstrated that sperm-ZP binding and enzymatic activities may be inhibited by specific antiacrosin antibodies.…”

Molecular genetic approaches to studying fertilization in model systems

“…Indeed, so successful were these strategies, that antibody-based strategies were even being touted as 'contraceptive vaccines' (Isojima et al 1986). Both speciesspecific antibodies as well as antibodies that affected fertilization in a wide variety of animals were generated by such techniques (Isojima et al 1984, Koyama et al 1985, Elce et al 1986). …”