title: Reversible contraceptive effect of PH-20 immunization in male guinea pigs.
abstract: Sperm proteins are currently being studied as antigens on which to base a contraceptive vaccine. Sperm plasma membrane proteins offer the theoretical possibility of immunizing either males or females and achieving a contraceptive effect. In this study, we investigated the sperm plasma membrane protein PH-20 as an antigen for inducing infertility in males. We found that infertility can reproducibly be induced in male guinea pigs immunized with purified PH-20: 100% (29 of 29) of PH-20-immunized males became infertile, whereas all 22 controls were fertile. The males were extremely responsive to PH-20 immunization: infertility could be induced with a single injection of only 5 microg PH-20. Among males that received their initial injection when they were approximately 300 g (body weight), 14 of 15 had regained fertility at about 1 yr after initial injection. Surprisingly, in another group of males that received their first injection when they were approximately 650 g (body weight), only 1 of 5 had regained fertility about 1 yr after initial injection. Anti-PH-20 titers in antisera (2 mo after initial injection) were generally in the range 1.1-4.2 x 10(4) in twice-injected males and the range 1.8-9.4 x 10(3) in once-injected males. Over the next 6-11 mo, twice-injected males' titers decreased > or = 4-fold, whereas once-injected males' titers decreased slightly (1.1 - to 1.8-fold). After 6-11 mo, anti-PH-20 titers were in the range 1.0-4.8 x 10(3), and the precise residual titer did not correlate with fertility/infertility. The results show that immunization of males with PH-20, even at low doses, results in a reproducible, completely effective contraceptive action.
authors.affiliation: Department of Physiology, University of Connecticut Health Center, Farmington 06030, USA. pdprimakoff@ucdavis.edu
authors.forename: P
authors.initials: P
authors.lastname: Primakoff
authors.forename: L
authors.initials: L
authors.lastname: Woolman-Gamer
authors.forename: K S
authors.initials: KS
authors.lastname: Tung
authors.forename: D G
authors.initials: DG
authors.lastname: Myles
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000941:Antigens / Q000008:administration & dosage; D015815:Cell Adhesion Molecules / Q000008:administration & dosage / Q000276:immunology*; D003269:Contraception, Immunologic / Q000379:methods*; D005260:Female; D006168:Guinea Pigs; D006821:Hyaluronoglucosaminidase; D007114:Immunization; D007248:Infertility, Male / Q000209:etiology / Q000276:immunology; D008297:Male; D011247:Pregnancy; D013094:Spermatozoa / Q000276:immunology*; D013997:Time Factors
chemical_list: D000941:Antigens; D015815:Cell Adhesion Molecules; D006821:Hyaluronoglucosaminidase; C066852:hyaluronidase PH-20