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Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate
Proefskrif (Ph. D.) -- Universiteit van Stellenbosch, 1992.
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| Format: | Thesis |
| Language: | Afrikaans |
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Stellenbosch : Stellenbosch University
2012
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| _version_ | 1867614112359383040 |
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| access_status_str | Open Access |
| author | Engelbrecht, Susan |
| author2 | Lecatsas, G. |
| author_browse | Engelbrecht, Susan Lecatsas, G. |
| author_facet | Lecatsas, G. Engelbrecht, Susan |
| author_sort | Engelbrecht, Susan |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Proefskrif (Ph. D.) -- Universiteit van Stellenbosch, 1992. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/57808 |
| institution | Stellenbosch University (South Africa) |
| language | Afrikaans |
| last_indexed | 2026-06-10T12:46:51.765Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2012 |
| publishDateRange | 2012 |
| publishDateSort | 2012 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/57808 Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate Engelbrecht, Susan Lecatsas, G. Van Heiden, P. D. Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology. Division of Medical Virology Virology HIV (Viruses) Dissertations -- Medicine Proefskrif (Ph. D.) -- Universiteit van Stellenbosch, 1992. One salient feature of the HIV-1 genome is the degree of variability that exists among the virus strains. Such heterogeneity raises important questions concerning antigenic diversity relative to vaccine development and laboratory diagnosis. No detailed study on HIV-1 variation in South Africa has been published. The purpose of the study described here was to characterize certain aspects of HIV-1 variation in South Africa and to determine the outcome of this variation on HIV-1 laboratory diagnosis. Nineteen HIV-1 strains, isolated at Tygerberg Hospital between 1984 and 1990, were investigated for variation. The virus strains were isolated from blood specimens and cocultured with normal peripheral blood lymphocytes. Virus infection in these cultures was detected by electron microscopy and reverse transcriptase activity in the cell culture supernatant fluid. The Southern blot hybridization technique and the polymerase chain reaction (PCR) were used to investigate the variation of the proviral DNA that had been isolated from infected cell cultures. Variation was found in Southern blot restriction sites. PCR using different primer pairs gave erratic results and the primers used did not detect proviral DNA in all the specimens. Evaluation of the patients' antibody responses to HIV-1 was determined using rapid test kits, ELISA screening tests and confirmatory Western blot tests. Although HIV-1 was isolated from all 19 patients, the serologic diagnosis could not be confirmed in all cases. False negative reactions were detected with tests using synthetic peptides and these patients' sera also showed indeterminate Western blot reactions. Variation in the patients' gp41 antibody response was also detected. Three strains were selected for further study of the variable membrane gene, based on the above results. Proviral DNA from one of the strains was cloned by preparing a genomic library in bacteriophage lambda. Proviral DNA from the other two strains was amplified by PCR and cloned in a plasmid. Nucleotide sequences derived from the cloned membrane gene were analysed with computer programs. The sequences were aligned and a phylogenetic tree was constructed which demonstrated that one of the strains was linked to prototype strains from USA/Europe and the other two strains were linked to Central African strains. The principal neutralizing determinant, the V3 loop, is a prime target for vaccine development and variation in the sequence at the tip of the loop should be studied more closely. A rare amino acid substitution was discovered in the sequence of HIV-1(R1296), that has been detected in only 2 of 245 strains. Amino acid substitutions in the immunodominant epitope of the gp41 transmembrane protein could explain the false negative serological results of patient R482. Fewer glycosylation sites, which influence the conformation of the membrane, were found in the membrane gene of HIV-1(R482). This could explain the poor serological reactions of the panel of 19 patients with the membrane antigen of HIV-1(R482). A nucleotide substitution in the 3' end of one of the PCR primer sets could also explain the variable results of HIV-1(R1296) DNA with the PCR tests. The conclusion is that variation in local strains can influence laboratory diagnosis of HIV-1. Identification and characterization of the prevalent strains will lead to improvement in the development of diagnostic tests specifically designed for local conditions. Doctoral 2012-08-27T11:38:40Z 2012-08-27T11:38:40Z 1992 Thesis http://hdl.handle.net/10019.1/57808 af Stellenbosch University 200 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Virology HIV (Viruses) Dissertations -- Medicine Engelbrecht, Susan Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate |
| title | Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate |
| title_full | Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate |
| title_fullStr | Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate |
| title_full_unstemmed | Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate |
| title_short | Karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 (HIV-1) isolate |
| title_sort | karakterisering van sekere aspekte van menslike immuungebrek virus tipe 1 hiv 1 isolate |
| topic | Virology HIV (Viruses) Dissertations -- Medicine |
| url | http://hdl.handle.net/10019.1/57808 |
| work_keys_str_mv | AT engelbrechtsusan karakteriseringvansekereaspektevanmenslikeimmuungebrekvirustipe1hiv1isolate |