title: A peptide enzyme linked immunosorbent assay (ELISA) for the detection of human immunodeficiency virus type-2 (HIV-2) antibodies: an evaluation on polymerase chain reaction (PCR) confirmed samples.
abstract: BACKGROUND
  HIV-1 and HIV-2 infections differ in prognosis, and may also require different prevention and/or treatment approaches. Thus, estimating the true prevalence of HIV-1 and HIV-2 infections, as well as co-infections, is a critical step in controlling the disease. There are a few commercial ELISA and immunoblot kits, which can differentiate between HIV-1 and HIV-2 infections. However, some of these assays overestimate the prevalence of dual infection. Hence, it is necessary to develop assays capable of discriminating between the two infections.
  
  
  OBJECTIVE
  To develop a synthetic HIV-2 env based peptide ELISA for the detection of HIV-2 specific antibodies and evaluate its performance on samples from HIV positive individuals previously tested by HIV-1 and HIV-2 PCR and HIV seronegative individuals.
  
  
  METHODS
  We studied 45 HIV seronegative and 63 HIV infected individuals, including 30 HIV-1 PCR and immunoblot positives, 19 HIV-2 PCR and immunoblot positives, five HIV-1 and two PCR and dual immunoblot positives, two PCR negative but positive for HIV-2 by immunoblot and seven dual immunoblot positives who were only positive for HIV-1 by PCR.
  
  
  RESULTS
  All 24 HIV-2 PCR positive samples tested were positive by the peptide assay. Among 30 HIV-1 PCR and immunoblot positive samples, only one (3.3%) showed an absorbance value above the cut off level. The seven dual positive samples by immunoblot (only positive for HIV-1 by PCR) were negative by the HIV-2 peptide ELISA. There was a 100% concordance between HIV-2 PCR and peptide ELISA. The sensitivity, specificity, and the likelihood ratio for the peptide ELISA were 100,94.9, and 19.5, respectively when compared against the PCR findings.
  
  
  CONCLUSIONS
  This ELISA, using a specific immunodominant epitope (11 amino acids) from the transmembrane (gp36) portion of the HIV-2 envelope glycoprotein showed a high concordance with PCR findings. This can be considered as a highly sensitive, specific and economically feasible assay for the discrimination of HIV-1 and HIV-2, and may serve as an alternative to HIV-2 PCR in epidemiological studies.
authors: Department of Clinical Virology, Christian Medical College Hospital, 632 004, Vellore, India.
authors: R
authors: R
authors: Kannangai
authors: S
authors: S
authors: Ramalingam
authors: K J
authors: KJ
authors: Prakash
authors: O C
authors: OC
authors: Abraham
authors: R
authors: R
authors: George
authors: R C
authors: RC
authors: Castillo
authors: D H
authors: DH
authors: Schwartz
authors: M V
authors: MV
authors: Jesudason
authors: G
authors: G
authors: Sridharan
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015686:Gene Products, env / Q000276:immunology; D015483:HIV Antibodies / Q000097:blood* / Q000276:immunology; D015658:HIV Infections / Q000097:blood / Q000276:immunology / Q000821:virology*; D015497:HIV-1 / Q000235:genetics; D015498:HIV-2 / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D010455:Peptides / Q000276:immunology; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D015686:Gene Products, env; D015483:HIV Antibodies; D010455:Peptides