Tissue- and Species-Specific Antigens of Normal Human Prostatic Tissue

Abstract

Abstract Heteroimmunization of rabbits with saline extracts of normal human prostatic tissue incorporating complete Freund's adjuvant produced antibodies reacting with saline extracts of normal human prostatic tissue as well as with comparable extract preparations of other human tissues and fluids as judged by the criteria of double diffusion gel precipitation and tanned cell hemagglutination. Rigorous absorption studies of rabbit antisera to extracts of normal human prostatic tissue accompanied by enhanced resolution of lines of precipitation following incubation of gel diffusion plates in a buffer-substrate mixture incorporating lead nitrate and sodium-β-glycerophosphate revealed that a portion of these antibodies were prostate-specific, and in addition permitted identification of two prostatic tissue-specific antigens. By specific immunochemical staining of the gel precipitation pattern, one of the prostate tissue-specific antigens was identified as prostatic acid phosphatase. Species-specificity studies of the antigens of the normal human prostate revealed that comparable antigens were absent from preparations of canine and rabbit prostatic tissue, but apparently shared to some degree with antigens of the cranial lobe of the monkey prostate. Several sera of patients with benign and malignant diseases of the prostate gave precipitation reactions accompanied by staining for prostatic acid phosphatase, but the relevance of such reactions remains to be determined. In addition, preliminary gel diffusion precipitation studies suggested specific antigenic differences between normal, benign and malignant prostatic tissue extracts. Immunoelectrophoretic analysis of extracts of normal human prostatic tissue and specifically absorbed homologous antisera revealed one arc of precipitation in the βγ-region of the electrophoretic field. Further resolution of immunoelectrophoretic patterns obtained by incubation in the buffer-substrate mixture and staining for acid phosphatase disclosed two to three additional lines of precipitation, the major arc of precipitation being identified as prostatic acid phosphatase. The sensitivity and specificity of rabbit antisera to extracts of normal human prostatic tissue as evaluated by gel diffusion precipitation and immunoelectrophoresis, as well as the development of this immunologic response, was confirmed by both direct tanned cell hemagglutination and inhibition of tanned cell hemagglutination.