scholarly journals Design and preclinical evaluation of a multigene human immunodeficiency virus type 1 subtype C DNA vaccine for clinical trial

2006 ◽  
Vol 87 (2) ◽  
pp. 399-410 ◽  
Author(s):  
Wendy A. Burgers ◽  
Joanne H. van Harmelen ◽  
Enid Shephard ◽  
Craig Adams ◽  
Thandiswa Mgwebi ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
South African ◽  
Dna Vaccine ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Consensus Sequence ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Hiv 1

In this study, the design and preclinical development of a multigene human immunodeficiency virus type 1 (HIV-1) subtype C DNA vaccine are described, developed as part of the South African AIDS Vaccine Initiative (SAAVI). Genetic variation remains a major obstacle in the development of an HIV-1 vaccine and recent strategies have focused on constructing vaccines based on the subtypes dominant in the developing world, where the epidemic is most severe. The vaccine, SAAVI DNA-C, contains an equimolar mixture of two plasmids, pTHr.grttnC and pTHr.gp150CT, which express a polyprotein derived from Gag, reverse transcriptase (RT), Tat and Nef, and a truncated Env, respectively. Genes included in the vaccine were obtained from individuals within 3 months of infection and selection was based on closeness to a South African subtype C consensus sequence. All genes were codon-optimized for increased expression in humans. The genes have been modified for safety, stability and immunogenicity. Tat was inactivated through shuffling of gene fragments, whilst maintaining all potential epitopes; the active site of RT was mutated; 124 aa were removed from the cytoplasmic tail of gp160; and Nef and Gag myristylation sites were inactivated. Following vaccination of BALB/c mice, high levels of cytotoxic T lymphocytes were induced against multiple epitopes and the vaccine stimulated strong CD8+ gamma interferon responses. In addition, high titres of antibodies to gp120 were induced in guinea pigs. This vaccine is the first component of a prime–boost regimen that is scheduled for clinical trials in humans in the USA and South Africa.

scholarly journals Extensive Intrasubtype Recombination in South African Human Immunodeficiency Virus Type 1 Subtype C Infections

2007 ◽  
Vol 81 (9) ◽  
pp. 4492-4500 ◽  
Author(s):  
Christine M. Rousseau ◽  
Gerald H. Learn ◽  
Tanmoy Bhattacharya ◽  
David C. Nickle ◽  
David Heckerman ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
South African ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Phylogenetic Signal ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Site Test ◽  
Hiv 1

ABSTRACT Recombinant human immunodeficiency virus type 1 (HIV-1) strains containing sequences from different viral genetic subtypes (intersubtype) and different lineages from within the same subtype (intrasubtype) have been observed. A consequence of recombination can be the distortion of the phylogenetic signal. Several intersubtype recombinants have been identified; however, less is known about the frequency of intrasubtype recombination. For this study, near-full-length HIV-1 subtype C genomes from 270 individuals were evaluated for the presence of intrasubtype recombination. A sliding window schema (window, 2 kb; step, 385 bp) was used to partition the aligned sequences. The Shimodaira-Hasegawa test detected significant topological incongruence in 99.6% of the comparisons of the maximum-likelihood trees generated from each sequence partition, a result that could be explained by recombination. Using RECOMBINE, we detected significant levels of recombination using five random subsets of the sequences. With a set of 23 topologically consistent sequences used as references, bootscanning followed by the interactive informative site test defined recombination breakpoints. Using two multiple-comparison correction methods, 47% of the sequences showed significant evidence of recombination in both analyses. Estimated evolutionary rates were revised from 0.51%/year (95% confidence interval [CI], 0.39 to 0.53%) with all sequences to 0.46%/year (95% CI, 0.38 to 0.48%) with the putative recombinants removed. The timing of the subtype C epidemic origin was revised from 1961 (95% CI, 1947 to 1962) with all sequences to 1958 (95% CI, 1949 to 1960) with the putative recombinants removed. Thus, intrasubtype recombinants are common within the subtype C epidemic and these impact analyses of HIV-1 evolution.

scholarly journals Enhanced immunogenicity using an alphavirus replicon DNA vaccine against human immunodeficiency virus type 1

2005 ◽  
Vol 86 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Eva K. L. Nordström ◽  
Mattias N. E. Forsell ◽  
Christina Barnfield ◽  
Eivor Bonin ◽  
Tomas Hanke ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Dna Vaccine ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Semliki Forest Virus ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

With the human immunodeficiency virus type 1 (HIV-1) epidemic expanding at increasing speed, development of a safe and effective vaccine remains a high priority. One of the most central vaccine platforms considered is plasmid DNA. However, high doses of DNA and several immunizations are typically needed to achieve detectable T-cell responses. In this study, a Semliki Forest virus replicon DNA vaccine designed for human clinical trials, DREP.HIVA, encoding an antigen that is currently being used in human trials in the context of a conventional DNA plasmid, pTHr.HIVA, was generated. It was shown that a single immunization of DREP.HIVA stimulated HIV-1-specific T-cell responses in mice, suggesting that the poor immunogenicity of conventional DNA vaccines may be enhanced by using viral replicon-based plasmid systems. The results presented here support the evaluation of Semliki Forest virus replicon DNA vaccines in non-human primates and in clinical studies.

scholarly journals Comprehensive Analysis of Human Immunodeficiency Virus Type 1-Specific CD4 Responses Reveals Marked Immunodominance of gag and nef and the Presence of Broadly Recognized Peptides

2004 ◽  
Vol 78 (9) ◽  
pp. 4463-4477 ◽  
Author(s):  
Daniel E. Kaufmann ◽  
Paul M. Bailey ◽  
John Sidney ◽  
Bradford Wagner ◽  
Philip J. Norris ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Consensus Sequence ◽  
Acute Infection ◽  
Hla Dr ◽  
Immunodeficiency Virus ◽  
Total Magnitude ◽  
Hiv 1

ABSTRACT Increasing evidence suggests that human immunodeficiency virus type 1 (HIV-1)-specific CD4 T-cell responses contribute to effective immune control of HIV-1 infection. However, the breadths and specificities of these responses have not been defined. We screened fresh CD8-depleted peripheral blood mononuclear cells (PBMC) from 36 subjects at different stages of HIV-1 infection for virus-specific CD4 responses by gamma interferon enzyme-linked immunospot assay, using 410 overlapping peptides spanning all HIV-1 proteins (based on the clade B consensus sequence). HIV-1-specific CD4 responses were identified in 30 of the 36 individuals studied, with the strongest and broadest responses detected in persons treated in acute infection who underwent treatment interruption. In individuals with identified responses, the total number of recognized HIV-1 peptides ranged from 1 to 36 (median, 7) and the total magnitude of responses ranged from 80 to >14,600 (median, 990) spot-forming cells/106 CD8-depleted PBMC. Neither the total magnitude nor the number of responses correlated with viremia. The most frequent and robust responses were directed against epitopes within the Gag and Nef proteins. Peptides targeted by ≥25% of individuals were then tested for binding to a panel of common HLA-DR molecules. All bound broadly to at least four of the eight alleles tested, and two bound to all of the HLA-DR molecules studied. Fine mapping and HLA restriction of the responses against four of these peptides showed a combination of clustering of epitopes and promiscuous presentation of the same epitopes by different HLA class II alleles. These findings have implications for the design of immunotherapeutic strategies and for testing candidate HIV vaccines.

scholarly journals CCR5- and CXCR4-Tropic Subtype C Human Immunodeficiency Virus Type 1 Isolates Have a Lower Level of Pathogenic Fitness than Other Dominant Group M Subtypes: Implications for the Epidemic

2009 ◽  
Vol 83 (11) ◽  
pp. 5592-5605 ◽  
Author(s):  
Awet Abraha ◽  
Immaculate L. Nankya ◽  
Richard Gibson ◽  
Korey Demers ◽  
Denis M. Tebit ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Ex Vivo ◽  
Sub Saharan Africa ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Subtype A ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) subtype C is the dominant subtype globally, due largely to the incidence of subtype C infections in sub-Saharan Africa and east Asia. We compared the relative replicative fitness (ex vivo) of the major (M) group of HIV-1 subtypes A, B, C, D, and CRF01_AE and group O isolates. To estimate pathogenic fitness, pairwise competitions were performed between CCR5-tropic (R5) or CXCR4-tropic (X4) virus isolates in peripheral blood mononuclear cells (PBMC). A general fitness order was observed among 33 HIV-1 isolates; subtype B and D HIV-1 isolates were slightly more fit than the subtype A and dramatically more fit than the 12 subtype C isolates. All group M isolates were more fit (ex vivo) than the group O isolates. To estimate ex vivo transmission fitness, a subset of primary HIV-1 isolates were examined in primary human explants from penile, cervical, and rectal tissues. Only R5 isolates and no X4 HIV-1 isolates could replicate in these tissues, whereas the spread to PM1 cells was dependent on active replication and passive virus transfer. In tissue competition experiments, subtype C isolates could compete with and, in some cases, even win over subtype A and D isolates. However, when the migratory cells from infected tissues were mixed with a susceptible cell line, the subtype C isolates were outcompeted by other subtypes, as observed in experiments with PBMC. These findings suggest that subtype C HIV-1 isolates might have equal transmission fitness but reduced pathogenic fitness relative to other group M HIV-1 isolates.

scholarly journals Neutralizing Antibody Responses in Acute Human Immunodeficiency Virus Type 1 Subtype C Infection

2007 ◽  
Vol 81 (12) ◽  
pp. 6187-6196 ◽  
Author(s):  
E. S. Gray ◽  
P. L. Moore ◽  
I. A. Choge ◽  
J. M. Decker ◽  
F. Bibollet-Ruche ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The study of the evolution and specificities of neutralizing antibodies during the course of human immunodeficiency virus type 1 (HIV-1) infection may be important in the discovery of possible targets for vaccine design. In this study, we assessed the autologous and heterologous neutralization responses of 14 HIV-1 subtype C-infected individuals, using envelope clones obtained within the first 2 months postinfection. Our data show that potent but relatively strain-specific neutralizing antibodies develop within 3 to 12 months of HIV-1 infection. The magnitude of this response was associated with shorter V1-to-V5 envelope lengths and fewer glycosylation sites, particularly in the V1-V2 region. Anti-MPER antibodies were detected in 4 of 14 individuals within a year of infection, while antibodies to CD4-induced (CD4i) epitopes developed to high titers in 12 participants, in most cases before the development of autologous neutralizing antibodies. However, neither anti-MPER nor anti-CD4i antibody specificity conferred neutralization breadth. These data provide insights into the kinetics, potency, breadth, and epitope specificity of neutralizing antibody responses in acute HIV-1 subtype C infection.

scholarly journals Human Leukocyte Antigen B58 Supertype and Human Immunodeficiency Virus Type 1 Infection in Native Africans

2006 ◽  
Vol 80 (12) ◽  
pp. 6056-6060 ◽  
Author(s):  
Aleksandr Lazaryan ◽  
Elena Lobashevsky ◽  
Joseph Mulenga ◽  
Etienne Karita ◽  
Susan Allen ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Leukocyte Antigen ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Human Leukocyte ◽  
Subtype C ◽  
Leukocyte Antigen ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human leukocyte antigen (HLA) class I alleles can be grouped into supertypes according to their shared peptide binding properties. We examined alleles of the HLA-B58 supertype (B58s) in treatment-naïve human immunodeficiency virus type 1 (HIV-1)-seropositive Africans (423 Zambians and 202 Rwandans). HLA-B and HLA-C alleles were resolved to four digits by a combination of molecular methods, and their respective associations with outcomes of HIV-1 infection were analyzed by statistical procedures appropriate for continuous or categorical data. The effects of the individual alleles on natural HIV-1 infection were heterogeneous. In HIV-1 subtype C-infected Zambians, the mean viral load (VL) was lower among B*5703 (P = 0.01) or B*5703-Cw*18 (P < 0.001) haplotype carriers and higher among B*5802 (P = 0.02) or B*5802-Cw*0602 (P = 0.03) carriers. The B*5801-Cw*03 haplotype showed an association with low VL (P = 0.05), whereas B*5801 as a whole did not. Rwandans with HIV-1 subtype A infection showed associations of B*5703 and B*5802 with slow (P = 0.06) and rapid (P = 0.003) disease progression, respectively. In neither population were B*1516-B*1517 alleles associated with more favorable responses. Overall, B58s alleles, individually or as part of an HLA-B-HLA-C haplotype, appeared to have a distinctive impact on HIV-1 infection among native Africans. As presently defined, B58s alleles cannot be considered uniformly protective against HIV/AIDS in every population.

scholarly journals Tat Protein of Human Immunodeficiency Virus Type 1 Subtype C Strains Is a Defective Chemokine

2004 ◽  
Vol 78 (5) ◽  
pp. 2586-2590 ◽  
Author(s):  
Udaykumar Ranga ◽  
Raj Shankarappa ◽  
Nagadenahalli B. Siddappa ◽  
Lakshmi Ramakrishna ◽  
Ramalingam Nagendran ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
The United States ◽  
Tat Protein ◽  
Subtype C ◽  
Monocyte Migration ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1)-associated dementia (HAD) is correlated with increased monocyte migration to the brain, and the incidence of HAD among otherwise asymptomatic subjects appears to be lower in India than in the United States and Europe (1 to 2% versus 15 to 30%). Because of the genetic differences between HIV-1 strains circulating in these regions, we sought to identify viral determinants associated with this difference. We targeted Tat protein for these studies in view of its association with monocyte chemotactic function. Analyses of Tat sequences representing nine subtypes revealed that at least six amino acid residues are differentially conserved in subtype C Tat (C-Tat). Of these, cysteine (at position 31) was highly (>99%) conserved in non-subtype C viruses and more than 90% of subtype C viruses encoded a serine. We hypothesized a compromised chemotactic function of C-Tat due to the disruption of CC motif and tested it with the wild type C-Tat (CS) and its two isogenic variants (CC and SC) derived by site-directed mutagenesis. We found that the CS natural variant was defective for monocyte chemotactic activity without a loss in the transactivation property. While the CC mutant is functionally competent for both the functions, in contrast, the SC mutant was defective in both. Therefore, the loss of the C-Tat chemotactic property may underlie the reduced incidence of HAD; although not presenting conclusive evidence, this study provides the first evidence for a potential epidemiologic phenomenon associated with biological differences in the subtype C viruses.

scholarly journals Human immunodeficiency virus type 1 subtype C Gag virus-like particle boost substantially improves the immune response to a subtype C gag DNA vaccine in mice

2004 ◽  
Vol 85 (2) ◽  
pp. 409-413 ◽  
Author(s):  
Ann Jaffray ◽  
Enid Shephard ◽  
Joanne van Harmelen ◽  
Carolyn Williamson ◽  
Anna-Lise Williamson ◽  
...  
Keyword(s):  
Immune Response ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Recombinant Baculovirus ◽  
Vaccination Strategy ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Hiv 1

Human immunodeficiency virus type 1 (HIV-1) subtype C is the predominant HIV in southern Africa, and is the target of a number of recent vaccine candidates. It has been proposed that a heterologous prime/boost vaccination strategy may result in stronger, broader and more prolonged immune responses. Since HIV-1 Gag Pr55 polyprotein can assemble into virus-like particles (VLPs) which have been shown to induce a strong cellular immune response in animals, we showed that a typical southern African subtype C Pr55 protein expressed in insect cells via recombinant baculovirus could form VLPs. We then used the baculovirus-produced VLPs as a boost to a subtype C HIV-1 gag DNA prime vaccination in mice. This study shows that a low dose of HIV-1 subtype C Gag VLPs can significantly boost the immune response to a single subtype C gag DNA inoculation in mice. These results suggest a possible vaccination regimen for humans.

scholarly journals 4E10-Resistant Variants in a Human Immunodeficiency Virus Type 1 Subtype C-Infected Individual with an Anti-Membrane-Proximal External Region-Neutralizing Antibody Response

2007 ◽  
Vol 82 (5) ◽  
pp. 2367-2375 ◽  
Author(s):  
Elin S. Gray ◽  
Penny L. Moore ◽  
Frederic Bibollet-Ruche ◽  
Hui Li ◽  
Julie M. Decker ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antibody Response ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibody ◽  
Subtype C ◽  
External Region ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The broadly neutralizing monoclonal antibody (MAb) 4E10 recognizes a linear epitope in the C terminus of the membrane-proximal external region (MPER) of gp41. This epitope is particularly attractive for vaccine design because it is highly conserved among human immunodeficiency virus type 1 (HIV-1) strains and neutralization escape in vivo has not been observed. Multiple env genes were cloned from an HIV-1 subtype C virus isolated from a 7-year-old perinatally infected child who had anti-MPER neutralizing antibodies. One clone (TM20.13) was resistant to 4E10 neutralization as a result of an F673L substitution in the MPER. Frequency analysis showed that F673L was present in 33% of the viral variants and in all cases was linked to the presence of an intact 2F5 epitope. Two other envelope clones were sensitive to 4E10 neutralization, but TM20.5 was 10-fold less sensitive than TM20.6. Substitutions at positions 674 and 677 within the MPER rendered TM20.5 more sensitive to 4E10 but had no effect on TM20.6. Using chimeric and mutant constructs of these two variants, we further demonstrated that the lentivirus lytic peptide-2 domain in the cytoplasmic tail affected the accessibility of the 4E10 epitope, as well as virus infectivity. Collectively, these genetic changes in the face of a neutralizing antibody response to the MPER strongly suggested immune escape from antibody responses targeting this region.

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