β5 integrin is the major contributor to the αVintegrin-mediated blockade of HIV-1 replication.

Monocytes and macrophages are targets of HIV-1 infection and play critical roles in multiple aspects of viral pathogenesis. During the differentiation of monocytes to macrophages, adhesion molecules such as integrins are upregulated; therefore, they provide signals that control the process and subsequently may render macrophages more susceptible to HIV-1 infection. Previous work demonstrated that blocking α(v)-containing integrins triggered a signal transduction pathway leading to the inhibition of NF-κB-dependent HIV-1 transcription. In this paper, we show the influence of the different α(v)-coupled β integrins in HIV-1 replication in macrophages. Inhibition of β integrins, either by specific mAbs, small arginine-glycine-aspartic acid (RGD) mimetic compounds, or RNA interference, showed that integrin β(5) was the major contributor to the integrin-mediated blockade of HIV-1 replication. Importantly, such inhibition did not induce changes in cell adhesion to the substrate. In conclusion, our results reveal a significant role of the integrin dimer α(v)β(5) in HIV-1 infection of macrophages.