title: Detection of HIV-p24 antigen in body fluids by immunotrapping on Staphylococcus aureus (Cowan 1) bacteria, gold immunolabelling and backscattered electron analysis in a scanning electron microscope.
abstract: An immunosorbent electron microscopical (ISEM) method, the Protein A-coated bacteria technique/gold, (PA-CBT/G), was developed for the detection of non-particulate soluble antigens. The method is based on immunotrapping of antigens on antibody coated, glutaraldehyde cross-linked, Protein A-rich, Staphylococcus aureus bacteria. The 'trapped' antigen is then identified by colloidal-gold immunolabelling. Gold particles are observed in a scanning/transmission electron microscope by analysis of backscattered electrons. With this method it was possible to detect the presence of p24 HIV antigens in blood, semen, saliva, crevicular and cerebrospinal fluids from HIV seropositive cases. Although the PA-CBT/G identified correctly the p24 antigen in only 80% of the ELISA HIV-antigen positive sera, it detected, more frequently than ELISA, HIV-antigen in seminal and oral fluids. The PA-CBT/G method could thus be useful to fully characterise individual HIV excretion patterns in body fluids other than sera even from patients negative for HIV-antigen by ELISA.
authors.affiliation: Department of Virology, Israel Institute for Biological Research, Ness-Ziona.
authors.forename: D
authors.initials: D
authors.lastname: Katz
authors.forename: M I
authors.initials: MI
authors.lastname: Herrera
authors.forename: L
authors.initials: L
authors.lastname: Cuevas
authors.forename: I
authors.initials: I
authors.lastname: Santa-María
authors.forename: C
authors.initials: C
authors.lastname: Casado
authors.forename: J M
authors.initials: JM
authors.lastname: Varela
authors.forename: R
authors.initials: R
authors.lastname: Nájera
mesh_terms: D001826:Body Fluids / Q000382:microbiology*; D003432:Cross-Linking Reagents; D004583:Electrons; D004797:Enzyme-Linked Immunosorbent Assay; D005976:Glutaral; D016655:HIV Core Protein p24 / Q000032:analysis*; D015658:HIV Infections / Q000175:diagnosis*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007163:Immunosorbent Techniques; D008297:Male; D008855:Microscopy, Electron, Scanning / Q000379:methods; D016253:Microscopy, Immunoelectron / Q000379:methods; D012542:Scattering, Radiation; D013205:Staphylococcal Protein A / Q000276:immunology; D013211:Staphylococcus aureus / Q000276:immunology / Q000648:ultrastructure
chemical_list: D003432:Cross-Linking Reagents; D016655:HIV Core Protein p24; D007074:Immunoglobulin G; D013205:Staphylococcal Protein A; D005976:Glutaral