IMMUNOHISTOCHEMISTRY OF SECRETORY PARTICLES (VESICULOSOMES) FROM THE EPITHELIUM OF BOVINE SEMINAL-VESICLES AND AMPULLA OF THE VAS-DEFERENS

Secretory particles, designated as 'vesiculosomes', were isolated and purified from bovine seminal vesicle fluid. The protein pattern was ch aracterized using one- and two-dimensional gel electrophoresis. Native vesiculosome fractions were used for immunization of female New Zeala nd rabbits. The resulting vesiculosome antiserum was used for immunohi stochemical studies, designed to obtain data on the intracellular form ation, the localization and the potential release from secretory cells of the respective proteins present in these particles. The specificit y and sensitivity of the antiserum was tested by Western blot analysis and by an ELISA system. Western blot analysis of isolated vesiculosom es separated on SDS-PAGE showed several heterogeneous immunoreactive b ands in the range of 16 kD and above 66 kD, indicating a polyvalent mi xture of immunoglobulins. Immunohistochemical staining of different bo vine tissues, nevertheless, revealed a strong reaction exclusively at the apical portion of secretory cells of the seminal vesicle and the a mpulla of the vas deferens and of intraluminal secretion. The antiseru m recognizes both secretory granules and plasma membrane proteins of s eminal vesicle epithelium, supporting the concept of vesiculosomes to represent cytoplasmic particles formed from plasma membranes surroundi ng apical 'blebs' of the cells that are released physiologically durin g secretion.