title: Expression of CD4 on human peripheral blood neutrophils.
abstract: CD4, the primary receptor for entry of HIV, is known to be expressed on T cells and monocytes/macrophages; healthy natural killer (NK) lymphocytes; in vitro human herpesvirus 6 (HHV6)-infected CD8+, NK, and gammadelta T lymphocytes; CD34+ progenitor cells; and a subset of eosinophils and basophils. We here report the unconventional expression of CD4 at the surface of peripheral blood neutrophils derived from 4 of 51 (7.8%) HIV-1-infected and 3 of 25 (12%) uninfected donors, with similar frequency within the 2 groups. The percentage of CD4+ neutrophils ranged from 39% to 97% of the total neutrophil population. Both surface and cytoplasmic forms of CD4 were present in neutrophils. Quantitative RNA polymerase chain reaction (PCR) revealed that neutrophils contain levels of CD4 mRNA comparable to those of peripheral blood mononuclear cells derived from the same donor. The conformation of CD4 expressed at the surface of neutrophils was similar to that of CD4 expressed on T lymphocytes as determined by the binding of monoclonal antibodies specific for conformational epitopes and the binding of recombinant HIV-1 gp120. Thus, our data provide evidence that neutrophils express endogenous CD4 and bind HIV. Owing to their abundance in peripheral blood, CD4+ neutrophils may influence significantly the biodistribution of HIV delivering it to sites of inflammation or to additional tissue reservoirs.
authors.affiliation: Laboratory of Clinical Immunology, San Raffaele Scientific Institute, Milan, Italy. priscilla.biswas@hsr.it
authors.forename: Priscilla
authors.initials: P
authors.lastname: Biswas
authors.forename: Barbara
authors.initials: B
authors.lastname: Mantelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Sica
authors.forename: Mauro
authors.initials: M
authors.lastname: Malnati
authors.forename: Carla
authors.initials: C
authors.lastname: Panzeri
authors.forename: Alessandra
authors.initials: A
authors.lastname: Saccani
authors.forename: Hamid
authors.initials: H
authors.lastname: Hasson
authors.forename: Andrea
authors.initials: A
authors.lastname: Vecchi
authors.forename: Abby
authors.initials: A
authors.lastname: Saniabadi
authors.forename: Paolo
authors.initials: P
authors.lastname: Lusso
authors.forename: Adriano
authors.initials: A
authors.lastname: Lazzarin
authors.forename: Alberto
authors.initials: A
authors.lastname: Beretta
mesh_terms: D001773:Blood Cells; D015704:CD4 Antigens / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D016022:Case-Control Studies; D005434:Flow Cytometry; D015699:HIV Envelope Protein gp120 / Q000378:metabolism; D015658:HIV Infections / Q000276:immunology / Q000473:pathology*; D006801:Humans; D016130:Immunophenotyping; D007963:Leukocytes, Mononuclear / Q000276:immunology; D009504:Neutrophils / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D012333:RNA, Messenger