Antigens During Spermatogenesis

Abstract

The germinal epithelial cells in the mammalian testis undergo an elaborate and orderly sequence of differentiation from spermatogonia to testicular spermatozoa, accompanied by morphological and chemical changes as well as by a reduction of genome from diploid to haploid as already discussed in Chaps. II, III, and IV. The marked changes in the proteins during spermatogenesis are by no means limited to chromatin constituents, but occur in other parts of the germ-cell as well. For example, the polypeptide components of membranes in the differentiating male germ-cells show conspicuous alterations during specific stages of spermatogenesis (Millette 1979a, O’Rand and Romrell 1980, Balbontin and Bustos-Obregon 1982, Moore et al. 1985). Of the many peptides synthesized during spermatogenesis, not all are antigenic. In most cases, the functional or metabolic roles of these sperm-specific proteins has not been identified. Proteins that have been purified from testes include some of defined function, e.g. enzymes, and some that play an as yet unknown structural role, e.g. plasma membrane components. Many of the proteins that are formed during spermatogenesis represent potential autoantigens, as sexual maturation starts long after immunologic maturity. Besides the various testis-specific enzymes, plasma membrane constituents of developing spermatogenic cells could be antigenic. Several antigens have been identified on the surface of testicular cells (Radu and Voisin 1975, Koo et al. 1977a, b, O’Rand and Romrell 1977, Millette and Bellvé 1977, Romrell and O’Rand 1978, Tung et al. 1979, Bebe Han and Tung 1979, Millette 1979a, Balbontin and Bustos-Obregon 1982, Söderström et al. 1982, Goldberg 1983, Narayan et al. 1983, O’Brien and Millette 1984).