A new SIV co-receptor, STRL33

The identification last year of chemokine receptors as fusion co-factors for HIV-11,2,3,4,5,6 has contributed significantly towards understanding HIV transmission and AIDS pathogenesis (see ref. 7 for a review). Because the experimental infection of rhesus macaques with simian immunodeficiency virus (SIV) and the resulting development of an AIDS-like illness is the best animal model for HIV disease in humans8, identifying SIV co-receptors analogous to those used by HIV has obvious importance. We now report that STRL33, a chemokine receptor-like orphan receptor expressed in activated human lymphocytes and acting as a fusion co-factor with envelope glycoproteins (Envs) from HIV-1 strains of diverse tropisms9, is a co-receptor for SIV.