title: Sialic acid-binding Ig-like lectin-7 interacts with HIV-1 gp120 and facilitates infection of CD4pos T cells and macrophages.
abstract: BACKGROUND
  Sialic acid-binding Ig-like lectin-7 (Siglec-7) expression is strongly reduced on natural killer (NK) cells from HIV-1 infected viremic patients. To investigate the mechanism(s) underlying this phenomenon, we hypothesized that Siglec-7 could contribute to the infection of CD4pos target cells following its interaction with HIV-1 envelope (Env) glycoprotein 120 (gp120).
  
  
  RESULTS
  The ability of Siglec-7 to bind gp120 Env in a sialic acid-dependent manner facilitates the infection of both T cells and monocyte-derived macrophages (MDMs). Indeed, pre-incubation of HIV-1 with soluble Siglec-7 (sSiglec-7) increases the infection rate of CD4pos T cells, which do not constitutively express Siglec-7. Conversely, selective blockade of Siglec-7 markedly reduces the degree of HIV-1 infection in Siglec-7pos MDMs. Finally, the sSiglec-7 amount is increased in the serum of AIDS patients with high levels of HIV-1 viremia and inversely correlates with CD4pos T cell counts.
  
  
  CONCLUSIONS
  Our results show that Siglec-7 binds HIV-1 and contributes to enhance the susceptibility to infection of CD4pos T cells and MDMs. This phenomenon plays a role in HIV-1 pathogenesis and in disease progression, as suggested by the inverse correlation between high serum level of sSiglec-7 and the low CD4pos T cell count observed in AIDS patients in the presence of chronic viral replication.
authors: Stefania
authors: S
authors: Varchetta
authors: Paolo
authors: P
authors: Lusso
authors: Kelly
authors: K
authors: Hudspeth
authors: Joanna
authors: J
authors: Mikulak
authors: Dalila
authors: D
authors: Mele
authors: Stefania
authors: S
authors: Paolucci
authors: Raffaello
authors: R
authors: Cimbro
authors: Mauro
authors: M
authors: Malnati
authors: Agostino
authors: A
authors: Riva
authors: Renato
authors: R
authors: Maserati
authors: Mario U
authors: MU
authors: Mondelli
authors: Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy. domenico.mavilio@humanitas.it.
authors: Domenico
authors: D
authors: Mavilio
mesh_terms: D000328:Adult; D000368:Aged; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000821:virology*; D005260:Female; D015699:HIV Envelope Protein gp120 / Q000378:metabolism*; D015497:HIV-1 / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D037102:Lectins / Q000378:metabolism*; D008264:Macrophages / Q000821:virology*; D008297:Male; D008875:Middle Aged; D011485:Protein Binding; D055815:Young Adult
chemical_list: D015214:Antigens, Differentiation, Myelomonocytic; D015699:HIV Envelope Protein gp120; D037102:Lectins; C402206:SIGLEC7 protein, human; C514793:gp120 protein, Human immunodeficiency virus 1