In vivo detection of specific cell-mediated immunity in street rabies virus infection in mice.

In street rabies-infected mice, in vivo expression of delayed type hypersensitivity (DTH) measured by the footpad test was revealed by challenge with inactivated fixed rabies virus (RV). The use of BCG as an adjuvant cell-mediated immunity (CMI) was necessary for the production of significant DTH levels. Typical DTH kinetics were obtained, with a maximum at 24 h after the challenge. DTH was also found to be at highest levels 4 days after infection with street rabies virus. DTH could also be revealed with street rabies virus in RV immunized mice. Adoptive transfer of lymphoid cells from a street rabies infected donor to normal recipient mice was performed and DTH was tested with RV. Susceptibility of DTH to immunosuppression by cyclophosphamide treatment was also assayed in street rabies virus-infected mice and in adoptively-sensitized recipient mice. These results and the relationship between DTH and CMI in rabies infection and immunization are discussed.