The role of T lymphocytes in the pathogenesis of Coxsackie virus B3 heart disease.

Myocarditis in athymic BALB/c-nu/nu (nu/nu) mice infected with Coxsackie virus B3 was studied to determine whether inflammatory mononuclear cell infiltration was produced by transfer of spleen cells ob BALB/c-nu/+ (nu/+) mice infected with the same virus. In addition, spleen cells of uninfected nu/+mice were transferred into athymic nu/nu mice infected with Coxsackie virus B3. Athymic nu/nu mice infected with Coxsackie virus B3 after transfer of spleen cells of nu/+ mice infected with the same virus developed marked to moderate myocarditis with inflammatory mononuclear cell infiltration. However, athymic nu/nu mice infected with Coxsackie virus B3 after transfer of spleen cells of uninfected nu/+ mice developed moderate to mild degeneration or necrosis of the muscle fibres, although mild mononuclear cell infiltration was found in only one mouse. The incidence of myocardial lesions of athymic nu/nu mice infected with Coxsackie virus B3 after transfer of infected-spleen cells of nu/+ mice was about the same is that in infected nu/+ mice after transfer of spleen cells of uninfected nu/+ mice. However, degrees in the intensity of the muscular changes and inflammatory mononuclear cell infiltration in the former was significantly greater than that in the latter. The results show, therefore, that Coxsackie virus B3 infection stimulated production of cytotoxic activity in the spleen which was evident on Day 6. From the present results, it is confirmed that myocarditis in mice infected with Coxsackie virus B3 is thymus-dependent, supporting previous investigations.