Cell cycle requisite for vesicular stomatitis virus replication in T lymphocytes activated with concanavalin A

The relationship between the development of virus plaque forming cells (V-PFC) and the blastogenic response of T cells activated with concanavalin A (Con A) was investigated in connection with the cell cycle using a modified virus plaque assay (VPA) which facilitated the quantitative detection of T lymphoblasts with low susceptibility to infection by vesicular stomatitis virus (vsv). The generation of V-PFC markedly decreased when DNA synthesis inhibitors such as thymidine, hydroxyurea and cytosine arabinoside (Ara C) were added to spleen cell cultures stimulated with Con A, while the addition of a mitotic inhibitor, Colcemid, to the cultures caused only partial reduction of V-PFC development. These results indicate that the S to G2 phases of the first cell cycle are essential for vsv-replication or V-PFC development in Con A activated T cells. However, vsv-replication in the activated T cells does not depend on the initial G1 phase during the blastogenic response since the morphological blast formation of activated T cells is not suppressed by treatment with DNA synthesis inhibitors.