PROACROSIN AS A MARKER OF MEIOTIC AND POSTMEIOTIC GERM-CELL DIFFERENTIATION - QUANTITATIVE ASSESSMENT OF HUMAN SPERMATOGENESIS WITH A MONOCLONAL-ANTIBODY

A quantitative immunohistochemical study of human spermatogenesis was performed using the 4D4 anti-proacrosin monoclonal antibody (mAb 4D4) as a marker of meiotic and post-meiotic germ cell differentiation. Cel ls from 15 testicular biopsies with normal spermatogenesis, 18 with sl ight and nine with marked hypospermatogenesis and six with maturation arrest were assigned to spermatogenic stages according to both nuclear maturation and proacrosin labelling patterns. The results showed that four spermatogenesis steps (mid- and late-pachytene primary spermatoc ytes, early and late spermatids) have to be separately considered for the classification of a given biopsy. Conversely, data from primary sp ermatocytes in the metaphase, anaphase and telophase stages and second ary spermatocytes did not show significant differences between biopsie s. We conclude that: (1) slight hypospermatogenesis is due only to few er cells entering meiosis, whereas in marked hypospermatogenesis there is also germ cell loss during the later meiotic steps and spermiogene sis; (2) the sloughing of germ cells from the epithelium could be of p athological significance; and (3) immunodetection with mAb 4D4 improve s the assessment of spermatogenesis because it can label a protein exp ressed as early as meiotic prophase. In addition, mAb 4D4 labels a pro tein which is a marker of the Golgi complex allowing the detection of disturbances of cytoplasmic events during meiosis or spermiogenesis. S uch an analysis is facilitated by mAb 4D4 labelling of paraffin-embedd ed sections.