Effects of CD45 on NF-kappa B. Implications for replication of HIV-1. 
Increased levels of replication of the HIV type 1 are observed after the activation of infected T cells through the TCR. However, anti-CD45 antibodies inhibit these effects in cells from infected individuals. In this study, we examined interrelationships between CD45 and HIV-1 further. We measured effects on the HIV-1 LTR in T cell lines that were stimulated with antibodies against CD45 and in those that lacked the expression of CD45 on their surfaces. First, anti-CD45 antibodies did not affect basal but decreased activated levels of expression from the HIV-1 LTR. Second, T cells, which lack CD45 and cannot signal via the TCR, supported higher levels of viral replication and gene expression. This was due to the presence of active NF-kappa B complexes in the nucleus of CD45- T cells. Additionally, infected T cells displayed lower levels of CD45 on their surfaces. Thus, CD45 plays an active role in the physiology of T cells and in the replication of HIV-1.