Siglecs facilitate HIV-1 infection of macrophages through adhesion with viral sialic acids (PDF)
Zou,Zhongcheng; Chastain,Ashley; Moir,Susan; Ford,Jennifer; Trandem,Kathryn; Martinelli,Elena; Cicala,Claudia; Crocker,Paul; Arthos,James; Sun,Peter D.
PLoS ONE 6(9): e24559-
Publication date: 2011
Human immunodeficiency virus type 1 (HIV-1) infects macrophages effectively, despite relatively low levels of cell surface-expressed CD4. Although HIV-1 infections are defined by viral tropisms according to chemokine receptor usage (R5 and X4), variations in infection are common within both R5- and X4-tropic viruses, indicating additional factors may contribute to viral tropism.
Methodology and Principal Findings
Using both solution and cell surface binding experiments, we showed that R5- and X4-tropic HIV-1 gp120 proteins recognized a family of I-type lectin receptors, the Sialic acid-binding immunoglobulin-like lectins (Siglec). The recognition was through envelope-associated sialic acids that promoted viral adhesion to macrophages. The sialic acid-mediated viral-host interaction facilitated both R5-tropic pseudovirus and HIV-1 infection of macrophages. The high affinity Siglec-1 contributed the most to HIV-1 infection and the variation in Siglec-1 expression on primary macrophages from different donors was associated statistically with sialic acid-facilitated viral infection. Furthermore, envelope-associated sialoglycan variations on various strains of R5-tropic viruses also affected infection.
Conclusions and Significance of the Findings
Our study showed that sialic acids on the viral envelope facilitated HIV-1 infection of macrophages through interacting with Siglec receptors, and the expression of Siglec-1 correlated with viral sialic acid-mediated host attachment. This glycan-mediated viral adhesion underscores the importance of viral sialic acids in HIV infection and pathogenesis, and suggests a novel class of antiviral compounds targeting Siglec receptors.
For 60 years, the Population Council has changed the way the world thinks about important health and development issues. Explore an interactive timeline of the Council's history, learn more about some of our key contributions, and watch a short video about why your support is so important to us.