Ultrastructural and immunocytochemical study of P1, protamine localization in human testis

Abstract
Two monoclonal antibodies (MAbs) directed against human protamine P1 were realized. Anti-P1 specificity was assessed by western-blot and confirmed by ELISA. Monoclonal antibody 97-3 was selected. Protamine P1 was specifically demonstrated in human testis by immunoelectron microscopy, using 97-3 MAb and an indirect post-embedding immunogold technique. Our results clearly demonstrated the precise time of appearance of P1 protamine in the nuclei of human spermatids. P1 first appeared in the nucleus of step 5 spermatids and its concentration was increased in steps 6-8 spermatids, cytoplasm was not labelled.