EXPERIMENTAL AUTOIMMUNE PROSTATITIS AND THE TRANSPORT OF ANTIGENS TO LYMPH NODE IN AGED RATS.

RÓPOLO, G. MORÓN, B. MALETTO AND MC PISTORESI-PALENCIA.

Punta del Este

Congreso; V Congreso Latinoamericano de Inmunología; 1999

We have been working within a model of Experimental Autoimmune Prostatitis (EAP) in Wistar rats and its association with age. In previous studies we found that 12-18 months old rats have an impaired humoral autoimmune response (Clin. Immunol. Immunopathol. 87,256-265, 1998). Therefore we studied the initial steps in the transport of antigen to lymphatic organs in normal and autoimmune rats of different ages. We used as antigen prostatic components (RAG) conjugated with fluorescein isothiocyanate (FITC) which gives an opportunity to directly detect by fluorescence those cells in lymph nodes that have taken up the antigen. We used autoimmune 3-, 12- and 18-month-old rats to s.c. injected the RAG-FITC, and 6 hs. post-injection we analyzed the fluorescent cells by flow citometry. Also we used monoclonal antibodies to recognized the different cells. We found that the percentages of RAG-FITC positive cells were 36±3% in three, 35±2% in twelve and 9±2% in 18-months-old rats. In all groups the fluorescent cells were MHC class II+, and some of them were also IgM+ cells (B cells). The diminished percentage of cells observed in 18 months old rats might results from a defect in the migration of RAG-FITC positive cells from the skin to lymph nodes. In order to issue this point we injected RAG-FITC in normal rats of different ages and we found that the percentages of fluorescent cells in 3 and 12-month-old rats were lower than in EAP rats (8±1%, and 9±1%,respectively). However 18 months old rats had a percentage comparable to the percentage found in autoimmune rats (10±1%). Also the RAG-FITC positive cells were MHC class II+ and some of them were IgM+, and the percentages of the total MHC class II+ cells were lower than in autoimmune rats in all groups. These results show that the induction of EAP in 18 month-old-rats do not trigger an increase in the number of RAG-FITC positive cells in the draining lymph nodes. This might contribute to the dimished humoral autoimmune response seen in old rats. (Grants: CONICET, CONICOR, SeCyt UNC)