Recombinant HIV type 2 gp36

Introduction: Among the several existing methods for the detection of antibodies to HIV, the 'sandwich' ELISA is currently the most used. This study aims to assess a biotinylated monomeric synthetic peptide of the glycoprotein trans-membrane gp36 from HIV-2, in a sandwich assay, for the detection of antibodies against this HIV-2 protein. Materials and methods: To perform the assay, plates coated with recombinant protein gp36 at 0.5 mu g/mL and synthetic peptide gp36(5) at 1 mu g/mL were used. The concentration of the biotinylated synthetic peptide (gp36(5)-B) used was 0.1 mu g/mL prepared with a Tris-BSA-NaCI buffer solution and the Streptavidin-Alkaline Phosphatase conjugate diluted 1:30000 prepared with a PBS-Sucrose-BSA solution. Positive serum samples to antibodies against HIV-1 and HIV-2 viruses (88 and 34, respectively) were tested, with 483 negative samples from blood donors and 96 serum samples to assess the analytical specificity. All the samples were tested using the UMELISA HIV 1+2 RECOMBINANT assay, and all positives were confirmed using a DAHIV-BLOT assay. Results: Thirty four samples with antibodies against HIV-2 were assessed as positive for both coating variants. The highest specificity was obtained with the variant using the synthetic peptide gp36(5) in its coating. The antigen 'sandwich' assay developed by using gp36(5)-B enables the detection of antibodies against gp36 protein of HIV-2 (C) 2014 Elsevier Espana, S.L.U. and Sociedad Espanola de Enfermedades Infecciosas y Microbiologia Clinica. All rights reserved.

Serological diagnosis of human immunodeficiency virus (HIV) based on detection of HIV antibodies is one of the easiest, cheapest and simplest assay. Synthetic peptides corresponding to immunodominant regions of envelope glycoprotein (gp41, V3 loop for HIV-1 and gp36 for HIV-2) were used in the present study, to detect the anti-HIV antibodies in sera of Sexually Transmitted Diseases (STD), Tuberculosis (TB), Anti-Natal Care (ANC) patients. About 550 serum samples were tested using Enzyme Linked Immunosorbent Assay (ELISA) technique. The human sera positive for antibody to HIV-1 and HIV-2, reacted to different degrees with these peptides when used as a plain peptide with or without CGG motif/biotin motif at the amino terminus. The selected sequences are of Indian strain with 'C' serotype. The results showed a 100% sensitivity and specificity for V3 loop peptide and 98% sensitivity and specificity for gp41 peptide containing CGG moiety while the plain peptides showed similar sensitivities but low specificity's, i.e. 98% for V3 loop peptide and 42% for gp41 peptide when reacted with HIV-1 positive sera. The presence of biotin at the amino terminus did not provide any beneficial effect in increasing the sensitivity although the specificity was enhanced for both the peptide sequences, i.e. gp41 and V3 loop peptide. Furthermore, the gp36 peptide containing CGG moiety detected the HIV-2 sera with 100% sensitivity and 98% specificity while the sensitivity and specificity of gp36 plain peptide was reduced to 98 and 90%. Thus the study overall highlighted the importance of synthetic peptides containing CGG moiety as a capture antigen in detecting both HIV-1&2 sera using an indigenously built ELISA system which is simple, cheap, sensitive and cost effective for rural areas. (C) 2002 Published by Elsevier Science B.V.