title: Virion attachment and entry: HIV gp120 Env biotinylation, gp120 Env, or integrin ligand-binding assay.
abstract: The HIV-1 entry receptors are CD4 and a chemokine receptor (CCR5 or CXCR4). In addition it has recently been demonstrated that HIV-1 gp120 binds to and signals through integrin α4β7, the gut-homing receptor (Arthos et al., Nat Immunol 9(3):301-309, 2008). Integrin α4β7 is not an entry receptor for HIV-1, although it can facilitate virion attachment to target cells (Arthos et al., Nat Immunol 9(3):301-309, 2008; Cicala et al., Proc Natl Acad Sci U S A 106:20877-20882, 2009). Recombinant HIV-1 gp120s bind to integrin α4β7 in a manner similar to its natural ligands (MAdCAM-1, V-CAM-1, fibronectin) (Andrew et al., J Immunol 153:3847-3861, 1994). gp120-α4β7 interactions are detected in a manner similar to assays developed for the natural ligands of α4β7. In this chapter we describe a method for the analysis of integrin-gp120 binding via a cell-based binding assay. In vitro ligand-integrin affinity can be modified by the presence of divalent cations (Mn(2+), Mg(2+), Ca(2+)) (Leitinger et al., Leitinger Biochim Biophys Acta 1498:91-98, 2000). Here we describe a protocol to detect biotinylated recombinant HIV-1 gp120 binding to integrin α4β7 in both primary cells and cell lines expressing the gut-homing receptor.
authors.affiliation: Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Cicala
authors.forename: James
authors.initials: J
authors.lastname: Arthos
mesh_terms: D000818:Animals; D019921:Biotinylation; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D057809:HEK293 Cells; D015699:HIV Envelope Protein gp120 / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D008024:Ligands; D011485:Protein Binding; D014771:Virion / Q000502:physiology*; D053585:Virus Attachment; D053586:Virus Internalization
chemical_list: D015699:HIV Envelope Protein gp120; D016023:Integrins; D008024:Ligands; C514793:gp120 protein, Human immunodeficiency virus 1