title: Envelope-specific antibody response in HIV-2 infection: C2V3C3-specific IgG response is associated with disease progression.
abstract: OBJECTIVE
  To examine the unspecific and envelope-specific IgA and IgG responses in acute and chronic HIV-2 infection.
  
  
  METHODS
  Twenty-eight chronically infected adults and two children with perinatal infection were studied. Total plasma concentrations of IgA and IgG were determined by nephelometry. IgA and IgG reactivity against the immunodominant region in gp36 and the C2V3C3 region in gp125 was tested with the enzyme-linked immunosorbent assay (ELISA)-HIV-2 assay. Clonal sequences of the C2V3C3 env region were obtained for most patients.
  
  
  RESULTS
  Total plasma IgG concentration, but not IgA, was significantly higher than normal in HIV-2 patients and correlated inversely with CD4 T-cell counts. Seroconversion to gp36 occurred during the first year of life in both infants. The infant with rapid disease progression did not elicit C2V3C3-specific antibodies. Most chronically infected patients produced plasma IgG1, IgG3 and IgA antibodies against gp36 and C2V3C3. Lack of C2V3C3-specific IgG response in two patients was associated with a major antigenic change in the V3 region. In longitudinal analysis, there was a significant inverse association between the C2V3C3-specific IgG antibody response and the number of CD4 T cells.
  
  
  CONCLUSIONS
  HIV-2 promotes an early, strong and broad gp36 and C2V3C3-specific IgG and IgA response. Increase in the IgG response against the envelope C2V3C3 region is associated with increased loss of CD4 T cells in chronically infected patients. These results provide further support for the immune protective role of the C2V3C3 envelope region during HIV-2 infection and have direct implications for HIV-2 diagnosis, clinical management and pathogenesis.
authors.affiliation: UTPAM, Departamento de Biotecnologia, Instituto Nacional de Engenharia Tecnologia e Inovação, Lisbon, Portugal.
authors.forename: José Maria
authors.initials: JM
authors.lastname: Marcelino
authors.forename: Charlotta
authors.initials: C
authors.lastname: Nilsson
authors.forename: Helena
authors.initials: H
authors.lastname: Barroso
authors.forename: Perpétua
authors.initials: P
authors.lastname: Gomes
authors.forename: Pedro
authors.initials: P
authors.lastname: Borrego
authors.forename: Fernando
authors.initials: F
authors.lastname: Maltez
authors.forename: Lino
authors.initials: L
authors.lastname: Rosado
authors.forename: Manuela
authors.initials: M
authors.lastname: Doroana
authors.forename: Francisco
authors.initials: F
authors.lastname: Antunes
authors.forename: Nuno
authors.initials: N
authors.lastname: Taveira
mesh_terms: D000328:Adult; D000368:Aged; D000917:Antibody Formation / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D015704:CD4 Antigens / Q000276:immunology*; D018791:CD4 Lymphocyte Count; D002648:Child; D018450:Disease Progression; D005260:Female; D015686:Gene Products, env / Q000276:immunology*; D015658:HIV Infections / Q000276:immunology* / Q000821:virology; D015498:HIV-2 / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D019562:Viral Load
chemical_list: D015415:Biomarkers; D015704:CD4 Antigens; D015686:Gene Products, env; D007070:Immunoglobulin A; D007074:Immunoglobulin G