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ABSTRACT: Resistance testing for treatment-naïve, recently HIV-infected persons is not currently recommended; its clinical value will depend on the prevalence of resistance-associated mutations among recently infected persons. To estimate this prevalence, specimens were collected during 1997-1999 in Seattle and Los Angeles from drug-naïve, recently HIV-infected persons. HIV-1 protease and reverse transcriptase (RT) RNA sequences were amplified from plasma by RT-polymerase chain reaction (RT-PCR), sequenced, and analysed. Of 69 patients, five (7%) had resistance-associated mutations: three (4%) had primary mutations associated with resistance to nucleoside reverse transcriptase inhibitors (NRTI) or non-nucleoside-RTIs, and three patients (4%) had secondary NRTI mutations. No primary mutation associated with resistance to protease inhibitors was observed. Mean age of the five persons with resistance-associated mutations (38 years) was higher than that of the 64 persons without resistance-associated mutations (31 years, P=0.04). The findings suggest that the prevalence of resistance-associated mutations among persons recently infected with HIV in these cities is low.
International Journal of STD & AIDS 09/2002; 13(8):554-8. · 1.09 Impact Factor
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S M Agwale,
C Zeh,
K E Robbins,
L Odama, A Saekhou,
A Edubio,
M Njoku,
N Sani-Gwarzo,
M S Gboun,
F Gao,
M Reitz,
D Hone,
D Pieniazek,
C Wambebe,
M L Kalish
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ABSTRACT: We conducted a national molecular epidemiologic survey of HIV-1 strains in Nigeria to determine the most prevalent subtype(s) for use in developing candidate vaccines. A total of 230 HIV-1-positive blood samples collected from 34 of the 36 Nigerian states were analyzed by our modified env gp41-based heteroduplex mobility assay (HMA) and/or gp41 sequencing and analysis. Overall, 103 (44.8%) were subtype A, 125 (54.3%) were subtype G, one (0.4%) was subtype C, and one (0.4%) was subtype J, and one (0.4%) was unclassifiable. To further characterize Nigerian viruses to aid in strain selection for candidate vaccines, one gp41 subtype G and five gp41 subtype A strains were selected for full envelope sequencing. The one subtype G sequence had consistent phylogenies throughout gp160, using programs to detect recombination. However, all five sequences that were primarily subtype A in gp41 were found to be recombinant viruses. Two of the five (40%) were A/G/J mosaics with common breakpoints. The remaining three gp160 recombinants all had their own unique break points: two A/? and one A/?/G, however, all five had the majority of their mosaic breakpoints occurring in gp41. None of the five were consistent with the circulating recombinant form (CRF)02_AG strain previously reported to be prevalent in West Africa. In conclusion, we showed a clear dominance and widespread distribution of gp41 subtypes A and G in fairly equal proportions, suggesting that vaccines designed for use in this geographic locale should incorporate the gene(s) of both subtypes. However, appreciating the magnitude of diversity of HIV-1 strains in Nigeria may require sequencing and analysis of longer gene regions for the identification of prevalent or emerging CRFs.
Vaccine 06/2002; 20(16):2131-9. · 3.77 Impact Factor
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S M Agwale,
K E Robbins,
L Odama, A Saekhou,
C Zeh,
A Edubio,
O M Njoku,
N Sani-Gwarzo,
M F Gboun,
F Gao,
M Reitz,
D Hone,
T M Folks,
D Pieniazek,
C Wambebe,
M L Kalish
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ABSTRACT: The gp120 region of the human immunodeficiency virus type 1 (HIV-1) envelope (env) gene exhibits a high level of genetic heterogeneity across the group M subtypes. The heteroduplex mobility assay (HMA) has successfully been used to assign subtype classifications, but C2V5 primers often fail to amplify African strains. We developed an env gp41-based HMA for which the target sequence is amplified with highly conserved gp41 primers, known to efficiently amplify nucleic acids from HIV-1 group M, N, and O viruses. By using gp41 from a new panel of reference strains, the subtype assignments made by our modified HMA were concordant with those obtained by sequencing and phylogenetic analysis of 34 field strains from 10 countries representing subtypes A to G. Testing of field strains from Nigeria further demonstrated the utility of this modified assay. Of 28 samples, all could be amplified with gp41 primers but only 17 (60.7%) could be amplified with the standard C2V5 primers. Therefore, gp41-based HMA can be a useful tool for the rapid monitoring of prevalent subtypes in countries with divergent strains of circulating HIV-1.
Journal of Clinical Microbiology 07/2001; 39(6):2110-4. · 4.15 Impact Factor
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ABSTRACT: The gp120 region of the human immunodeficiency virus type 1 (HIV-1) envelope (env) gene exhibits a high level of genetic heterogeneity across the group M subtypes. The heteroduplex mobility assay (HMA) has successfully been used to assign subtype classifications, but C2V5 primers often fail to amplify African strains. We developed an env gp41-based HMA for which the target sequence is amplified with highly conserved gp41 primers, known to efficiently amplify nucleic acids from HIV-1 group M, N, and O viruses. By using gp41 from a new panel of reference strains, the subtype assignments made by our modified HMA were concordant with those obtained by sequencing and phylogenetic analysis of 34 field strains from 10 countries representing subtypes A to G. Testing of field strains from Nigeria further demonstrated the utility of this modified assay. Of 28 samples, all could be amplified with gp41 primers but only 17 (60.7%) could be amplified with the standard C2V5 primers. Therefore, gp41-based HMA can be a useful tool for the rapid monitoring of prevalent subtypes in countries with divergent strains of circulating HIV-1.
Journal of Clinical Microbiology. 01/2001; 39:2110–2114.
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ABSTRACT: In this study we characterized the immunogenic properties of three different multispecies multiple antigen constructs (MACs) carrying the circumsporozoite protein (CSP) repeats of human malaria parasites, Plasmodium falciparum and P. vivax. We synthesized tetrameric MACs containing the antigenic repeats from the CSP of P. vivax-like parasite in two arms and CSP repeat sequences of either P. vivax type-1 (vivax-like/vivax type-1 MAC), P. vivax type-2 (vivax-like/vivax type-2 MAC), or P. falciparum (vivax-like/falciparum MAC) in the other two arms. Mice of four different genetic backgrounds (H-2a, H-2b, H-2d, and H-2k) were immunized with these MACs in Freund's adjuvant. All three MAC preparations were found to elicit antibodies to P. vivax-like CSP repeats in B10.BR, B10.A, and C57BL/6 mice. On the other hand, in B10.D2 mice only vivax-like/vivax type-1 MAC, but not the other two MACs induced antibodies to the P. vivax-like CSP repeats. In mice immunized with vivax-like/vivax type-1 MAC, antibodies to P. vivax type-1 CS repeat peptides were induced in B10.BR, B10.A, and C57BL/6 mice, but not in B10.D2 mice. Antibody responses to P. vivax type-2 repeats were not induced in any of the four strains of mice that were immunized with vivax-like/vivax type-2 MAC. While B10.BR, B10.A, and C57BL/6 mice produced antibodies to NANP repeats of P. falciparum CSP following immunization with vivax-like/falciparum MAC, B10.D2 mice failed to elicit antibodies to this repeat. All the sera that showed positive reactivity to peptides in enzyme-linked immunosorbent assay were found to react with sporozoites by IFA. In conclusion, these results showed that naturally immunogenic epitopes from different species of malaria parasites can be incorporated in a single vaccine construct to induce immune responses against multiple epitopes.
Vaccine 16(9-10):982-8. · 3.77 Impact Factor
