Ultrastructural study of mouse thymus virus replication.
With the exception of thymocytes, no other cell types have been reported to be involved in mouse thymus virus (MTV) infection. The ultrastructure of thymuses of mice infected with MTV were examined. The earliest sign of infection was detected 5 days p.i.; lymphocytes, epithelial and phagocytic (macrophages) reticular cells were shown to be affected. Viral particles and filamentous structures were present in both the nucleus and the cytoplasm of these cells. At more severe stages of cellular necrosis, 6 and 7 days p.i., cytoplasmic granulation as well as loss in definition of cytoplasmic organelles became apparent. This was followed by nuclear degradation and aggregation of cells. After 9 days p.i. necrotic lesions were still observed but viral particles were no longer detectable. This study provides evidence of the susceptibility of macrophages to MTV.