Monoclonal antibodies against human prostasomes.

BACKGROUND The prostasomes are secreted into the gland ducts of the human prostate. At ejaculation, these native prostasomes are expelled with the secretions of the prostate and appear in the seminal plasma as seminal prostasomes, where they facilitate sperm function in various ways. We have designed methods for producing monoclonal anti-prostasome antibodies to be used for immunohistochemistry and sequencing analyses of the prostasomes. METHODS The immunogen applied was purified seminal prostasomes placed on small pieces of nitrocellulose membranes (prostasome blots) and deposited into the spleen of mice for immunization. For screening, both seminal and native prostasomes were used. RESULTS We obtained antibodies which detected native prostasomes both in prostatic secretions and in paraffin sections of the prostate. The immunostaining demonstrated that all prostate epithelial cells contained prostasomes. They were located in the apical parts of the secretory cells and in the gland ducts, while the nuclei and the corpora amylacea were unstained. CONCLUSIONS Using the methods described, monoclonal antibodies against native prostasomes were produced. In addition to their usefulness in structural and functional studies of prostasomes, specific monoclonal antibodies can be used to characterize prostasomes by sequencing analyses. Prostate 35:178–184, 1998. © 1998 Wiley-Liss, Inc.