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M9650950.TXT
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Document 0950
DOCN M9650950
TI Enhanced specificity of truncated transmembrane protein for serologic
confirmation of human T-cell lymphotropic virus type 1 (HTLV-1) and
HTLV-2 infections by western blot (immunoblot) assay containing
recombinant envelope glycoproteins.
DT 9505
AU Varma M; Rudolph DL; Knuchel M; Switzer WM; Hadlock KG; Velligan M; Chan
L; Foung SK; Lal RB; Department of Pathology, Stanford University,
California 94305,; USA.
SO J Clin Microbiol. 1995 Dec;33(12):3239-44. Unique Identifier : AIDSLINE
MED/96156135
AB Immunoassays based on the highly immunogenic transmembrane protein of
human T-cell lymphotropic virus type 1 (HTLV-1) (protein 21c) are
capable of detecting antibodies in all individuals infected with HTLV-1
and HTLV-2. However, because of antigenic mimicry with other cellular
and viral proteins, such assays also have a large proportion of
false-positive reactions. We have recently identified an immunodominant
epitope, designated GD21-I located within amino acids 361 to 404 of the
transmembrane protein, that appears to eliminate such false positivity.
This recombinant GD21-I protein was used in conjunction with additional
recombinant HTLV type-specific proteins and a whole virus lysate to
develop a modified Western blot (immunoblot) assay (HTLV WB 2.4). The
sensitivity and specificity of this assay were evaluated with 352
specimens whose infection status was determined by PCR assay for the
presence or absence of HTLV-1/2 proviral sequences. All HTLV-1-positive
(n = 102) and HTLV-2-positive (n = 107) specimens reacted with GD21-1 in
the HTLV WB 2.4 assay, yielding a test sensitivity of 100%. Furthermore,
all specimens derived from individuals infected with different viral
subtypes of HTLV-1 (Cosmopolitan, Japanese, and Melanesian) and HTLV-2
(IIa0, a3, a4, IIb1, b4, and b5) reacted with GD21-I in the HTLV WB 2.4
assay. More importantly, HTLV WB 2.4 analysis of 81 PCR-negative
specimens, all of which reacted to recombinant protein 21e in the
presence or absence of p24 and p19 reactivity in the standard WB assay,
showed that only two specimens retained reactivity to GD21-I, yielding
an improved test specificity for the transmembrane protein of 97.5%.
None of 41 specimens with gag reactivity only or 21 HTLV-negative
specimens demonstrated reactivity to GD21-I. In an analysis of
additional specimens (n = 169) from different geographic areas for which
PCR results were not available, a substantial increase in the
specificity of GD21-I detection was demonstrated, with no effect on the
sensitivity of GD21-I detection among specimens from seropositive
donors. Thus, the highly sensitive, GD21-I-based HTLV WB 2.4 assay
eliminates the majority of false-positive transmembrane results, thereby
increasing the specificity for serologic confirmation of HTLV-1 and
HTLV-2 infections.
DE Amino Acid Sequence Blotting, Western/*METHODS/STATISTICS & NUMER DATA
Comparative Study False Positive Reactions Gene Products,
env/GENETICS/IMMUNOLOGY Human HTLV-I/GENETICS/IMMUNOLOGY HTLV-I
Antibodies/BLOOD HTLV-I Infections/*DIAGNOSIS/IMMUNOLOGY/VIROLOGY
HTLV-II/GENETICS/IMMUNOLOGY HTLV-II Antibodies/BLOOD HTLV-II
Infections/*DIAGNOSIS/IMMUNOLOGY/VIROLOGY Immunodominant
Epitopes/GENETICS Molecular Sequence Data Polymerase Chain Reaction
Recombinant Proteins/GENETICS/IMMUNOLOGY Sensitivity and Specificity
Sequence Homology, Amino Acid Serodiagnosis/METHODS/STATISTICS & NUMER
DATA Support, U.S. Gov't, P.H.S. JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).