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Biomedical subjects

G Beelaert

Publications and source records attributed to G Beelaert.

9 recordsLinked to original sources

Evaluation of an agglutination HIV-1 + 2 antibody assay.

Studies have shown that an HIV (HIV-PA) agglutination assay (Serodia) for the detection of antibody to human immunodeficiency virus (HIV) can be as sensitive and as specific as enzyme-linked immunosorbent assay (ELISA). However, since this HIV assay was designed to detect antibody to the HIV-1 virus, a substantial number of HIV-2 positive sera are missed by this assay. Since the HIV-2 has now been found throughout the world this test is becoming less suitable. The new HIV-1 + 2 assay version (HIV-1 + 2 PA) was evaluated in 300 sera, which contained 50 HIV-1, 40 HIV-2 and 10 HIV-1/HIV-2 antibody positive samples, and a sensitivity and specificity of 100% and 99%, respectively, was obtained. Whereas all HIV-2 positive sera were detected by the new HIV-1 + 2 version, 26% (13/50) were missed by the old version of the agglutination test. It is concluded that the HIV-1 + 2 PA assay is a promising instrument free assay which can be used for screening purposes in areas where both HIV-1 and HIV-2 are present.

AIDS Serodiagnosis

Eradication of hantavirus infection among laboratory rats by application of caesarian section and a foster mother technique.

Hantavirus antibodies were demonstrated by the indirect immunofluorescent antibody assay, in the serum of inbred strains of laboratory rats, during the period 1973-1982, at the Unit of Experimental Immunology in the Catholic University of Louvain, Brussels, Belgium. LOU rats, as well as immunocytomas, which were requested by laboratories in the U.K. and The Netherlands, were supplied at a time when the infection was unknown and unsuspected in Europe. Hantavirus-infected laboratory rats were rendered free of virus through re-derivation by caesarian section and suckling by virus-free foster mothers. Immunocytomas were tested for the presence of hantaviruses by implantation into seronegative laboratory rats. The strain of hantavirus causing the laboratory infection was clearly different from the one circulating in free-living bankvoles in Belgium. The exchange of laboratory rats and rat tumours in relation to the potential risk of laboratory-acquired hantavirus infection, is discussed.

Animals

Evaluation of a line immunoassay for simultaneous confirmation of antibodies to HIV-1 and HIV-2.

An anti-HIV-1/HIV-2 line immunoassay (LIA), using peptides and recombinant antigens was evaluated against commercially available Western blot tests for HIV-1 and HIV-2 antibodies. Two thousand one hundred and ten sera of European, African, and South American origin were used in the evaluation. The panel included 1066 sera with antibodies to HIV-1, 192 sera with antibodies to HIV-2, and 64 sera with antibodies to both. Using Western blot results interpreted according to the WHO criteria as a reference standard, the overall specificity obtained by this LIA was 100% and the sensitivity was 99.77% (97.51-100% for 95% confidence limits) when sera dually reactive in Western blot were included. Of the three sera negative in the LIA but positive in HIV-1 WB, two could be retested in a radioimmunoprecipitation assay and were negative. When dually reactive sera in the Western blot (WHO) were included, the LIA yielded 9.9% indeterminate results as compared with 15.5% for both assays (chi 2 = 29.30; p less than 0.001). Although only one HIV-2 specific peptide antigen (gp36) was used, the LIA yielded a specificity of 100% and a sensitivity of 100% as compared with the HIV-2 Western blot assay. When indeterminate results were included, the overall agreement between the LIA and the HIV-1 and HIV-2 Western blot (WHO criteria) was 89.9% and 90.1% respectively. These results indicate that the LIA provides reliable simultaneous detection of antibodies to HIV-1 and HIV-2, and at a cost which is substantially lower than the cost of Western blot tests.

Blotting, Western

Confirmation and differentiation of antibodies to human immunodeficiency virus 1 and 2 with a strip-based assay including recombinant antigens and synthetic peptides.

We evaluated the use of the INNO-LIA HIV-1/HIV-2 Ab test (LIA HIV; Innogenetics) for the confirmation of antibodies to human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2). The test includes three recombinant HIV-1 proteins: p24 (gag), p17 (gag), and endonuclease (p31; pol), in combination with two synthetic peptides derived from the env gene of HIV-1 and one synthetic peptide selected from the env gene of HIV-2. Analysis of 450 sera from blood donors, 220 sera from patients with non-HIV pathology, and 28 Western blot (WB) p24-only reactive sera revealed no false-positive results, and the rate of indeterminate results was substantially lower than that with WB. Testing of 334 WB-confirmed HIV antibody-positive sera (309 HIV-1; 25 HIV-2) revealed no false-negative results. In two of seven seroconversion panels tested, LIA HIV detected the presence of HIV antibodies before WB did. In the other five panels, LIA HIV and WB confirmed the presence of HIV antibodies in the same sample. The LIA HIV assay therefore appears well suited for routine confirmation of the presence of HIV-1 and HIV-2 antibodies.

Antibodies, Viral

Line immunoassay and enzyme-linked line immunofiltration assay for simultaneous detection of antibody to two treponemal antigens.

Two enzyme immunoassays, the line immunoassay (LIA) and the enzyme-linked line immunofiltration assay (ELLIFA), were studied for suitability in the serodiagnosis of syphilis. In both assays, antibody to treponemes was detected using the recombinant DNA derived treponemal protein TmpA and the purified axial filament derived from the Reiter treponeme. The antigens were applied in parallel lines onto nitrocellulose membranes. The sensitivity and specificity of both assays were compared with that of the Treponema pallidum hemagglutination assay (TPHA), the fluorescent treponemal antibody absorption test, and the axial filament and TmpA enzyme-linked immunosorbent assays. The sensitivity and specificity of the LIA and the ELLIFA were found to be comparable to that of the TPHA using serum samples from 65 untreated syphilitic patients, 95 patients treated for syphilis and 60 blood donors, except in the case of the LIA using axial filament. This latter test was slightly less sensitive in primary and early latent syphilis than the TPHA. In the LIA procedure, serum antibodies to two antigens could be detected simultaneously within two hours. This assay may be useful for fieldwork. In the ELLIFA procedure, antibodies to the two antigens could be detected simultaneously within 15 minutes. The ELLIFA procedure may provide a multiple antigen test with a very short assay operation time.

Antibodies, Bacterial

Partial characterization of a Hantavirus isolated from a Clethrionomys glareolus captured in Belgium.

A Hantavirus was isolated in Vero-E6 cells from lungs of a free living bank vole (Clethrionomys glareolus) captured in Turnhout, Province of Antwerp--Northern part of Belgium. With help of monoclonal antibodies the Belgian Hantavirus isolate could be clearly differentiated from Hantaan virus strain 76-118, Prospect Hill virus strain PH1 and SR11, a Hantavirus isolated from laboratory Wistar rat in Japan, but not from the nephropathia epidemica virus strain Hällnäs.

Animals

Immunoperoxidase assay for the detection of specific IgG antibodies to Hantaan virus.

A technique, using indirect immunoperoxidase antibody (IPA), was developed for the detection of IgG antibody to Hantaan virus. The same protein A-peroxidase conjugate was used with mouse, rat and human sera. The IPA technique employs glass slides with air-dried gamma-ray-inactivated and acetone-fixed Hantaan-infected Vero-E6 cells. Antibody titers detected by IPA was comparable to those detected by the indirect fluorescent antibody technique.

Animals