Blocking of in vitro and in vivo susceptibility to mouse hepatitis virus

By pretreatment with concanavalin A (Con A) both in vivo and in vitro genetically susceptible mice and their cultured macrophages have been converted to animals and cells which are phenotypically resistant to mouse hepatitus virus (MHV). Con A at 1.0 mg/mouse decreased the mortality from 100% to less than 40% by inducing a prominent inflammatory response, increasing the number of macrophages in the virus inoculation site, and producing a population of macrophages not uniformly susceptible to the virus. In addition, mediators derived from Con A-treated spleen cells conferred resistance to normally susceptible syngeneic macrophages to 100 TCID50 of MHV.