Experimental autoimmune
prostatitis (EAP) is a disease that could be considered an experimental model of human non-bacterial
prostatitis. In this experimental model, male rats are intradermally immunized with a saline extract of male sex accessory glands (RAG) in an adequate adjuvant. The
prostatitis observed in the immunized animals develops as a consequence of the immune response against RAG
antigens, and the histological lesion is strikingly similar to the pattern of prostatic
inflammation observed in the human disease. In this study, we purified one of the prostatic
autoantigens recognized by the
autoantibodies in our model. Amino acid sequence analysis identified the purified
protein as
prostatein or rat
prostatic steroid binding protein, a member of the
uteroglobin superfamily.
Prostatein was recognized not only by the humoral autoimmune response, but also by the cellular autoimmune response. Certainly, the DTH response and lymph node cell proliferative assays against
prostatein in immunized animals yielded positive results.
Prostatein is not only the target of the autoimmune response in animals immunized with the whole extract, but also an inducing
antigen of the disease. Purified
prostatein, when incorporated to an adequate adjuvant, elicited cellular and humoral autoimmune response and lesion in the prostate gland. The identification of one of the target
antigens in autoimmune
prostatitis has provided a further refinement and characterization of our model, which could serve for a better understanding of the aetiology, pathogenesis and pathophysiology of non-bacterial
prostatitis.