Evaluation of testicular sperm CRISP2 as a potential target for contraception.
Cysteine-rich secretory protein 2 (CRISP2) is a testicular sperm protein  proposed to be involved in fertilization. With the aim of examining the  relevance of CRISP2 for fertility and its potential use as a target for  contraception, in the present work, male and female rats were immunized with  recombinant CRISP2 coupled to maltose-binding protein (MBP) and evaluated for  their subsequent fertility. As controls, animals were injected with either MBP  or recombinant CRISP1. Enzyme-linked immunosorbent assay of sera collected at  different intervals after immunization indicated that CRISP2 immunization  raised specific antibodies in both sexes, with levels that increased as a  function of time. Western blot studies revealed that anti-CRISP2 sera were  capable of recognizing CRISP2 in testicular, epididymal, and sperm extracts,  whereas histological studies showed no evidence of autoimmune orchitis or  epididymitis. Indirect immunofluorescence experiments revealed the ability of  anti-CRISP2 sera to recognize the native sperm protein in fresh, capacitated,  and ionophore-induced acrosome-reacted cells. Moreover, anti-CRISP2 sera  significantly inhibited the sperm ability to penetrate zona-free eggs,  confirming the role of CRISP2 in rat gamete fusion. In spite of the presence  of circulating anti-CRISP2 antibodies capable of inhibiting the sperm  fertilizing ability, mating studies revealed no effects of CRISP2 immunization  on male or female fertility, in contrast to the significant inhibition  observed in both sexes in animals injected with CRISP1. Together, these  observations indicated the immunogenic properties of testicular CRISP2 but do  not support CRISP2 as a target for immunocontraception or as a molecule  responsible for generating autoimmune orchitis or immunoinfertility.
Instituto de Biologia y Medicina Experimental, CONICET, Vuelta de Obligado 2490, Buenos Aires 1428, Argentina.
Mariana Weigel
MW
Muñoz
Juan I
JI
Ernesto
Carolina
C
Bluguermann
Dolores
D
Busso
María A
MA
Battistone
Débora J
DJ
Cohen
Patricia S
PS
Cuasnicú
D000818:Animals; D015815:Cell Adhesion Molecules; D003269:Contraception, Immunologic; D005260:Female; D005306:Fertilization / Q000502:physiology*; D006023:Glycoproteins / Q000276:immunology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000276:immunology; D013075:Sperm Capacitation
C062790:CRISP2 protein, rat; D015815:Cell Adhesion Molecules; D006023:Glycoproteins; D011994:Recombinant Proteins