APPEARANCE OF NATURAL ANTISPERM AUTOANTIBODIES AFTER SEXUAL-MATURATION OF NORMAL LEWIS RATS

Serum antisperm antibodies were assessed quantitatively with an ELISA in normal male Lewis rats at intervals between ages 10 and 128 days, s panning the onset of puberty. Antisperm antibodies rose between 56 and 91 days, and were significantly higher in 91- and 128-day old rats th an at earlier intervals. The animals underwent normal pubertal develop ment as indicated by increases in weights of the seminal vesicles and ventral prostate. The rise in antisperm antibodies correlated temporal ly with events in the postnatal development of the male reproductive s ystem, with the increase in antisperm antibodies most closely followin g the time when spermatozoa reach the epididymis and proximal vas defe rens at approximately 56 days. The observation that serum antisperm an tibodies increased only after sexual maturation suggests that some dif ferentiation antigens of sperm are processed and presented to the immu ne system under normal circumstances in this strain. Western blot anal ysis showed that the sera from normal postpubertal Lewis rats bound se veral proteins, including bands of > 100, 82-75, 78, 68, 65, 63, 54-55 , 42, 37, 35, 26, and 20-22 kDa. The majority of these autoantibodies were sperm-specific as shown by the absence of comigrating bands in we stern blots of somatic tissue extracts, although antibodies in postpub ertal sera recognized certain other proteins in somatic tissues. Sever al protein autoantigens, defined by sera from postpubertal animals, ma tched dominant autoantigens recognized by antibodies produced in respo nse to vasectomy, prepubertal vas obstruction, or immunization with sp ermatozoa. This finding indicates that the antisperm antibody response s following sperm immunization, vasectomy or prepubertal vasal obstruc tion represent accentuation of an autoantibody response to sperm that develops normally following puberty. (C) 1997 Elsevier Science Ireland Ltd.