Chemokine Receptors: Keys to AIDS Pathogenesis? Dan R Littman Cell Volume 93, Issue 5, Pages 677-680 (May 1998) DOI: 10.1016/S0092-8674(00)81429-4
Figure 1 Basis of HIV-1 Cellular Tropism Previous nomenclature for viral tropism is noted at the bottom. Macrophage-tropic viruses were also named NSI (non-syncytium-inducing in T cell lines), whereas T cell line–tropic viruses were named SI (syncytium-inducing). These viruses are now named R5 and X4, respectively. Cell 1998 93, 677-680DOI: (10.1016/S0092-8674(00)81429-4)