Introduction DEAE-D is a potent adjuvant in inactivated foot-and-mouth disease and Aujeszky disease vaccines, enhancing antibody formation and protection against challenge infection, especially in pigs (SKODA and WITTMANN, 1973; WITTMANN et al., 1970 WITTMANN et al., , 1972. It has been demonstrated that inactivated virus is not adsorbed to DEAE-D, and that DEAE-D exerts its adjuvant effect even if it is separately injected locally and temporally from the inactivated virus WITTMANN et al., 1975). In vitro stimulation experiments with mouse lymphocytes (BARTENBACH and WITTMANN, 1976) showed that DEAE-D is a weak mitogen for these lymphocytes, acting apparently upon B and T cells.By using combinations of DEAE-D with concanavalin A, and lipopolysaccharide it was demonstrated that DEAE-D considerably enhances B and T cell stimulation by these mitogens, thereby favouring the T cell response. From these experiments it is concluded that DEAE-D enhances the immunologic reactivity of immunocompetent cells.To gain more information on this subject we have investigated the effect of DEAE-D on the stimulation of lymphocytes from ADV infected and noninfected pigs using virus antigen and virus-free antigen. These experiments were part of more comprehensive investigations on cell-mediated immunity against ADV (WITTMANN et al., 1976). The present paper deals with the influence of DEAE-D on virus specific lymphocyte stimulation.
Material and Methods
Animals and Lymphocyte PreparationFor the experiments 4'12 to 5 month old pigs of the breed "Deutsches Landschwein" were used. Nine animals were intranasally infected with 108 Abbrevations: ADV = Aujeszky disease virus; ADVSA = ADV soluble antigen; cpm = counts per min; DEAE-D = diethylaminoethyl dextran; NSA = non viral soluble antigen.
Influence of DEAE Dextran upon Pig Lymphocyte Stimulation
813TCD,, of ADV, strain Phylaxia, 5th passage in BHK 21 clone CT cells. Pig no. 1 was slaughtered 4 days, pig no. 2 one week, pig no. 3 two weeks, pig no. 4 three weeks, pig no. 5 four weeks, and pig no. 6 five weeks after infection. Pigs no. 7, 8 and 9 were reinfected 4 weeks after the first infection and no. 7 slaughtered one week and no. 8 and 9 two weeks after reinfection. Furthermore, 3 non-infected 5 month old pigs (no. 10, 11 and 12) were slaughtered as controls.Further details concerning virus, cell cultures, course of infection as well as preparation of lymphocyte suspensions from retropharyngeal lymph nodes, thymus and bone marrow have been published elsewhere (WITTMANN et al., 1976).
In Vitro Lymphocyte StimulationLymphocyte cultures from the various tissues (8 X lo6 lymphocytes in 2ml.) were treated with DEAE-D (MW 5 X lo5; Pharmacia, Uppsala, Sweden) 50 p g . per culture, ADVSA and NSA (0.2 ml. per culture) as well as with combinations of with ADVSA (0.2 ml.) or NSA (0.2 ml.). Lymphocyte cultures without DEAE-D and antigen served as controls. The culture medium consisted of Eagle's minimal essential medium supplement with heat-inactivated (56 "C/30 min.) fetal calf serum, and pe...