The NF-kappa B binding site is necessary for efficient replication of simian immunodeficiency virus of macaques in primary macrophages but not in T cells in vitro.

We demonstrate here that the nuclear factor-kappa B (NF-kappa B) binding site in the simian immunodeficiency virus (SIVmac) long terminal repeat is essential for efficient virus replication in primary alveolar macrophages but dispensable for efficient replication in primary T cells. Mutation of the NF-kappa B site does not seriously impair replication of a T-cell-tropic SIVmac239 or a macrophagetropic SIVmacEm* in peripheral blood lymphocytes or established CD4+ cell lines; however, mutation of the NF-kappa B site prevents efficient SIVmacEm* replication in primary alveolar macrophages. These data suggest that efficient replication in primary macrophages requires both envelope and long terminal repeat determinants.