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103 HIV-1 gp120 Interactions With the Gut Homing Receptor Integrin α4β7 on CD4+ T Cells

Arthos J.; Nawaz, F.; Wei, D.; Van Ryk, D.; Jelicic, K.; Pascuccio, M.; Cicala, C.; Fauci, A. S.
JAIDS Journal of Acquired Immune Deficiency Syndromes: April 2012
doi: 10.1097/01.qai.0000413750.62137.66
Abstract: PDF Only

Mucosal transmission of HIV is inefficient. The virus must breach physical barriers before it infects mucosal CD4+ T cells. Low-level viral replication occurs initially in mucosal CD4+ T cells, but within days high-level replication occurs in Peyer's patches, mesenteric lymph nodes and the gut lamina propria. The viral quasispecies in a donor contracts through a genetic bottleneck in the recipient, such that infection is typically established by a single founder virus. Founder viruses in subtypes A and C mucosal transmission tend to encode gp120s with reduced numbers of N-linked glycosylation sites at specific positions throughout the V1- V4 domains, relative to typical chronically replicating isolates. The transmission advantage gained by the absence of these N-linked glycosylation sites is unknown.Using primary α4β7+/CD4+ T cells and a flow-cytometry based steady-state binding assay we have determined that the removal of transmission-associated N-linked glycosylation sites from chronic subtype A and C envelopes results in large increases in the specific reactivity of gp120 for integrin-α4β7. These results suggest that the genetic bottleneck reported at the time of transmission may frequently involve a requirement for the productive infection of α4β7+/CD4+ T cells. Understanding the structural features of the HIV envelope that promote reactivity with integrin α4β7 receptor may help define early events in HIV transmission.

© 2012 Lippincott Williams & Wilkins, Inc.