Paralysis of street rabies virus-infected mice is dependent on T lymphocytes

Street rabies virus (SRV)-infected T-lymphocyte-deficient (nude) mice, in contrast to euthymic mice, did not develop hindlimb paralysis prior to death. To document the role of T lymphocytes in rabies virus-associated paralysis, 10⁸ spleen cells from normal immunocompetent euthymic mice were transferred to nude mice and the recipient mice were challenged with SRV. One hundred percent of the reconstituted mice developed paralysis and died. Depletion of T cells from the donor spleen suspension prior to transfer abrogated the development of paralysis but did not prevent the deaths of the recipient animals. Mice receiving 10⁸ rabies virus-immune spleen cells did not become paralyzed and did not die. Nude mice inoculated with either rabies virus-immune or normal mouse serum prior to and following SRV inoculation did not develop paralysis. Immune serum protected the mice, whereas animals inoculated with normal serum died. Central nervous system inflammatory responses in nude mice immunologically reconstituted with normal spleen cells were characterized by diffuse cellular infiltrates in the parenchyma and extensive perivascular cuffing. Perivascular infiltrates included CD8⁺ and CD4⁺ T lymphocytes and Mac-1⁺ macrophage-microglial cells. Inflammatory cells in the parenchyma were limited to CD8⁺ lymphocytes and Mac-1⁺ cells. These observations indicate that paralysis of SRV-infected mice is dependent on T lymphocytes. Whether injury leading to paralysis is mediated by T lymphocytes or by an influence of T lymphocytes on macrophage-microglial cells or other cells remains to be determined.