The integrin alpha4beta7 forms a complex with cell-surface CD4 and defines a T-cell subset that is highly susceptible to infection by HIV-1.

Cicala, Claudia; Martinelli, Elena; McNally, Jonathan P; Goode, Diana J; Gopaul, Ravindra; Hiatt, Joseph; Jelicic, Katija; Kottilil, Shyamasundaran et al. · Proc Natl Acad Sci U S A · 2009

basic_science · Level V

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Abstract

Both activated and resting CD4(+) T cells in mucosal tissues play important roles in the earliest phases of infection after sexual transmission of HIV-1, a process that is inefficient. HIV-1 gp120 binds to integrin alpha(4)beta(7) (alpha(4)beta(7)), the gut mucosal homing receptor. We find that alpha(4)beta(7)(high) CD4(+) T cells are more susceptible to productive infection than are alpha(4)beta(7)(low-neg) CD4(+) T cells in part because this cellular subset is enriched with metabolically active CD4(+) T cells. alpha(4)beta(7)(high) CD4(+) T cells are CCR5(high) and CXCR4(low); on these cells, alpha(4)beta(7) appears in a complex with CD4. The specific affinity of gp120 for alpha(4)beta(7) provides a mechanism for HIV-1 to target activated cells that are critical for efficient virus propagation and dissemination following sexual transmission.

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