Human T-Cell Lymphotropic Virus Types I and II (HTLV-I/-II) Antibody Screen with Confirmation, Serum
Method Description Describes how the test is performed and provides a method-specific reference
Human T-Cell Lymphotropic Virus Types I and II (HTLV-I/II) Antibody Screen:
The Avioq HTLV-I/II Microelisa System is an enzyme-linked immunosorbent assay in which the solid phase (Microwells) is coated with a purified HTLV-I viral lysate, a purified HTLV-II viral lysate, and a recombinant HTLV-I p21E antigen. With the addition of a diluted test sample containing antibodies to either HTLV-I or HTLV-II, complexes are formed by the interaction of the antibodies in the sample and the solid phase antigens. Following incubation, the sample is aspirated and the well is washed with buffer. Subsequently, anti-human immunoglobulin (goat) conjugated with horseradish peroxidase (HRP) is added which binds the antibody-antigen complex during a second incubation. Following a wash and incubation with TMB (tetramethylbenzidine) substrate, a blue color is produced. The enzyme reaction is stopped by the addition of a sulfuric acid solution which changes the color to yellow. The amount of antibody present in the sample is proportional to color development.(Package insert: Avioq HTLV-I/II Microelisa System, Avioq, Inc., Research Triangle Park, NC, March 2012)
INNO-LIA HTLV I/II is a line immunoassay that uses well-defined antigens derived from HTLV-I and HTLV-II immunodominant proteins. The antigens used are either recombinant proteins or synthetic peptides, highly purified and fixed on a nylon membrane strip. The sequences are selected to allow the detection of antibodies with a wide specificity to all known isolates of the HTLV strains. The antigenicity exhibited by these proteins and peptides is either common to both HTLV-I and HTLV-II, or type-specific to 1 of the 2 viruses to allow confirmation and discrimination in a single assay. Two gag (p19-I/II, p24-I/II) and 2 env (gp46-I/II, gp21-I/II) bands are applied as nontype-specific antigens, which are used to confirm the presence of antibodies against HTLV-I/II. The type-specific antigens for HTLV-I (gag p19-I, env gp46-I) and for HTLV-II (env gp46-II) are applied to differentiate between HTLV-I and HTLV-II infections. In addition, 4 control lines are coated: 1 negative control (streptavidin), and 3 positive control lines, a strong (antihuman IgG), a moderate (human IgG), and a weak (human IgG) line.
This assay is based on the enzyme immunoassay principle. Specific anti-HTLV antibodies, if present in the clinical sample, will bind to the HTLV antigen lines on the strip. Subsequently, goat antihuman IgG antibodies labeled with alkaline phosphatase are added and will bind to any HTLV antigen-antibody complex previously formed. Incubation with a chromogenic substrate produces a dark brown color in proportion to the amount of specific antibodies present in the sample. The color development is stopped with sulfuric acid. If the sample contains no HTLV-specific antibodies, only a low background color develops.
Every sample is classified as negative, indeterminate, or positive, then further classified as HTLV-I, HTLV-II, or untypeable-positive according to the antibody band reactivity.(Package insert: INNO-LIA HTLV I/II Score kit 25957 v5; INNOGENETICS N.V., Gent, Belgium)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
HTLV-I/-II Antibody Screen: Monday through Friday; varies
HTLV-I/-II Antibody Confirmation: Wednesday; 3 p.m.