Lectin binding sites on human sperm and spermatogenic cells

Abstract

Testes of sexually mature men were studied histochemically with 20 fluorescein isothiocyanate-labeled lectins. Based on their pattern of reactivity with intratesticular spermatogenic cells, lectins were divided into five groups: 1) lectins reacting with all spermatogenic cells (Suc. ConA, WGA, LCA, PHA-E, PHA-L, STA, MPA, and RCA-II); 2) lectin reacting with spermatocytes, spermatids, and spermatozoa, but not with spermatogonia (RCA-I); 3) lectins reacting with spermatids and spermatozoa only (BPA, PNA, SBA, and VVA); 4) lectins reacting only with spermatozoa (HPA, GSA-I, UEA-II, and GSA-II); and 5) lectins with no distinct staining of spermatogenic cells (DBA, LBA, and UEA-I). All lectins from groups 1-4 were reactive with ejaculated spermatozoa. On the basis of the staining patterns of the head region of ejaculated spermatozoa, four lectin reactivity groups were defined: 1) lectins reacting with the plasma membrane of the whole head (BPA, WGA, LCA, STA, RCA-II, PHA-E, PHA-L, RCA-I, UEA-II, and GSA-II); 2) lectin reacting with the acrosomal cap and postacrosomal region of the plasma membrane (Suc. ConA); 3) lectin reacting with the acrosomal cap region of the plasma membrane (PNA); and 4) lectins reacting with the midregion of the sperm head in a bandlike manner (HPA, VVA, SBA, GSA-I, and MPA). These data provide a map of lectin binding sites on human testicular spermatogenic cells and ejaculated spermatozoa and show that the distribution of glycoconjugate domains of spermatogenic cell changes during differentiation and maturation.