AUTOANTIBODIES AGAINST RAT PROSTATE ANTIGENS - ASSOCIATION OF SPECIFIC IGG2B AND IGG2C WITH THE DTH RESPONSE

Although autoimmune response against most tissues in the body has been extensively described, very Little is known about autoimmune response against prostate antigens either in humans or animals. In this work w e studied the autoimmune response elicited against rat prostate (RP) i n Wistar rats immunized with a chemically modified extract of syngenei c male sex accessory glands (MRAG). We observed that one immunization was enough for the induction of positive delayed-type hypersensitivity test (DTH), which was higher on day 15 than on day 30. It was also en ough to induce IgG autoantibodies to RP although a second injection wa s necessary to obtain a more frequent occurrence and a greater reactiv ity. The autoantibodies against RP were directed mainly to the cytosol ic fraction and reacted at least with two molecules of 43 and 20 KD. S era obtained on days 30 and 45 showed presence of specific IgG, IgA an d IgM. Specific IgG2b and IgG2c were found on both days. On day 30 non e of the sera presented IgG2a anti-RP, while on day 45 only 38% of the sera were considered positive for this isotype. No IgG1 anti-RP was d etected in any serum of either bleeding. Direct immunofluorescence sta ining showed intense immunofluorescence in prostate epithelium, mainly in the apical zone of the gland, in animals that had received two imm unizations with MRAG-CFA. No positive staining was seen in prostates o btained on day 30 after just one immunization, in sections of normal p rostates or in sections of other rat organs. Our data indicate that th e main isotypes involved in this autoimmune phenomenon are IgG2b and I gG2c. A strong association between the cellular autoimmune response me asured by the DTH response and the IgG2b and IgG2c isotype was found a t early stages of the disease. Since the DTH response and the IgG2b is otype have been previously associated with Th1-like activity in rats, our results suggest that Th1-like cells could be playing an active rol e in early stages of this disease. (C) 1996 Academic Press Limited