OBJECTIVE It may happen that the virus infection causes changes of the immunogenicity of the host cells that may theoretically result in disturbances of the "self-recognition" of the organism. In this paper we report on the immunization of rabbits by autologous testes cells infected with herpes-virus hominis (HVH) types 1 and 2. METHODS In 20 rabbits the excision of one testis was carried out. The testes cells were cultivated in L 15-medium (Leibowitz) and lactalbumine hydrolysate supplemented with 12% autologous serum. The virus strains herpesvirus hominis type 1 (Kupka) and type 2 (US) were passaged three times on autologous testes cells, in order to remove host-foreign proteins out of the envelope. Thereafter, the monolayer cultures grown in Demeter flasks were infected with 15 ml virus suspension containing 10(4) to 10(5) TCID50. For the immunization three antigen preparations were applied: a) Supernatant of virus-infected cell cultures, b) Pellets of the virus-infected cell cultures, c) Pellets of the non-infected cell cultures. Two times at an interval of 3 weeks the animals were immunized by intramuscular and intraperitoneal injections with prepared antigens. Altogether, 20 animals were immunized: 15 rabbits with virus antigen, 5 control animals with non-infected autologous cells. After 28 days, 13 rabbits were bled, the second testis, liver, spleen, and kidneys were taken out. From 7 rabbits, only the second testis was taken out. These animals got a further injection on the 40th day post infectionem, and on the 50th day, they were bled. From the tissue samples, frozen sections were cut, fixed with acetone, and treated with fluorescein isothiocyanate-labelled antirabbit globulin, in order to elicite the tissue-bound antibodies. For histological studies, paraffin sections were stained with hematoxylin and eosin, and with azan, besides the PAS reaction was carried out. The determination of humoral antibodies was done by means of indirect-immunofluorescence antibody technique (IFAT). As antigen, autologous cells grown on slides were used; a part of them was infected with HVH types 1 or 2, while another part was not infected. RESULTS After immunization with autologous testes cells which were infected with HVH types 1 or 2, histologically homogeneous eosinophilic PAS-positive substances were detected in 14 out of 15 rabbits, mainly in the interstitium of the testes (fig. 2). These substances corresponded to globulin deposits that could be demonstrated by the reaction of labelled antirabbit globulin (fig. 1). The testes sections of thoses 5 rabbits that were injected with noninfected autologous cells, did not react. On the 28th day post infectionem, the antibody levels against virus antigen were found at the degree of 1:32 to 1:1024. Only after the removal of the second testis, there occurred antibodies against autologous testes cells. The immunization conditions exclude the formation of isoantibodies...