Multiprotein HIV Type 1 Clade B DNA/MVA Vaccine: Construction, Safety, and Immunogenicity in Macaques

Self Cite

“…Consistent with our prior trials using i.m. inoculations of DNA, T-cell responses were not detected until after the first MVA boost (data not shown) (21,34).…”

Section: Resultsmentioning

confidence: 96%

Preclinical Studies of Human Immunodeficiency Virus/AIDS Vaccines: Inverse Correlation between Avidity of Anti-Env Antibodies and Peak Postchallenge Viremia

Zhao

Lai

Amara

et al. 2009

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“…That the recombinant elicited a lesser cell-mediated immune response in macaques perhaps reflects the multiple differences between mouse and human immunology (36), here extended to nonhuman primates. Other studies with rhesus macaques using vectored vaccine candidates have reported widely varying ELISPOT responses to Tat immunogens (30,52). This variability may result from the different vaccine regimens but could also reflect differences in MHC haplotypes.…”

Section: Discussionmentioning

confidence: 99%

A Replication-Competent Adenovirus-Human Immunodeficiency Virus (Ad-HIV)tatand Ad-HIVenvPriming/Tat and Envelope Protein Boosting Regimen Elicits Enhanced Protective Efficacy against Simian/Human Immunodeficiency Virus SHIV_89.6PChallenge in Rhesus Macaques

Demberg

Florese

Heath

et al. 2007

We previously demonstrated that replication-competent adenovirus (Ad)-simian immunodeficiency virus (SIV) recombinant prime/protein boost regimens elicit potent immunogenicity and strong, durable protection of rhesus macaques against SIV mac251 . Additionally, native Tat vaccines have conferred strong protection against simian/human immunodeficiency virus SHIV 89.6P challenge of cynomolgus monkeys, while native, inactivated, or vectored Tat vaccines have failed to elicit similar protective efficacy in rhesus macaques. Here we asked if priming rhesus macaques with replicating Ad-human immunodeficiency virus (HIV) tat and boosting with the Tat protein would elicit protection against SHIV 89.6P . We also evaluated a Tat/Env regimen, adding an Ad-HIV env recombinant and envelope protein boost to test whether envelope antibodies would augment acute-phase protection. Further, expecting cellular immunity to enhance chronic viremia control, we tested a multigenic group: Ad-HIV tat, -HIV env, -SIV gag, and -SIV nef recombinants and Tat, Env, and Nef proteins. All regimens were immunogenic. A hierarchy was observed in enzyme-linked immunospot responses (with the strongest response for Env, followed by Gag, followed by Nef, followed by Tat) and antibody titers (with the highest titer for Env, followed by Tat, followed by Nef, followed by Gag). Following intravenous SHIV 89.6P challenge, all macaques became infected. Compared to controls, no protection was seen in the Tat-only group, confirming previous reports for rhesus macaques. However, the multigenic group blunted acute viremia by approximately 1 log (P ‫؍‬ 0.017), and both the multigenic and Tat/Env groups reduced chronic viremia by 3 and 4 logs, respectively, compared to controls (multigenic, P ‫؍‬ 0.0003; Tat/Env, P < 0.0001). The strikingly greater reduction in the Tat/Env group than in the multigenic group (P ‫؍‬ 0.014) was correlated with Tat and Env binding antibodies. Since prechallenge anti-Env antibodies lacked SHIV 89.6P -neutralizing activity, other functional anti-Env and anti-Tat activities are under investigation, as is a possible synergy between the Tat and Env immunogens.

“…AF457066) were obtained from the Henry Jackson Modifications of each env gene included (i) removal of the 5TNT early transcription termination signal by silent codon alterations using a site-directed mutagenesis kit (Stratagene, La Jolla, CA) (9), (ii) addition of nucleotides ACC immediately before the initiating ATG for optimal translation (14), and (iii) truncation of the C terminus of the cytoplasmic tail following the sequences GGGEQD, EGGEQG, and EGGEQD for AG, UGD, and KEA env, respectively (34). Three mutations were introduced into the AG gag-pol gene to inactivate reverse transcriptase, strand transfer, and RNase H activities, and the integrase was deleted as previously described (25). The gag-pol genes of UGD and KEA were truncated to delete the RNase H and integrase, and two mutations were made in the active site of the reverse transcriptase.…”

Section: Methodsmentioning

confidence: 99%

Elucidating and Minimizing the Loss by Recombinant Vaccinia Virus of Human Immunodeficiency Virus Gene Expression Resulting from Spontaneous Mutations and Positive Selection

Wyatt

Earl

Xiao

et al. 2009

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While characterizing modified vaccinia virus recombinants (rMVAs) containing human immunodeficiency virus env and gag-pol genes, we detected nonexpressing mutants by immunostaining individual plaques. In many cases, the numbers of mutants increased during successive passages, indicating strong selection pressure. This phenomenon provided an opportunity to investigate the formation of spontaneous mutations in vaccinia virus, which encodes its own cytoplasmic replication system, and a challenge to reduce the occurrence of mutations for vaccine production. Analysis of virus from individual plaques indicated that loss of expression was due to frameshift mutations, mostly by addition or deletion of a single nucleotide in runs of four to six Gs or Cs, and large deletions that included MVA DNA flanking the recombinant gene. Interruption of the runs of Gs and Cs by silent codon alterations and moving the recombinant gene to a site between essential, highly conserved MVA genes eliminated or reduced frameshifts and viable deletion mutants, respectively. The rapidity at which nonexpressing mutants accumulated depended on the individual env and gag-pol genes and their suppressive effects on virus replication. Both the extracellular and transmembrane domains contributed to the selection of nonexpressing Env mutants. Stability of an unstable Env was improved by swapping external or transmembrane domains with a more stable Env. Most dramatically, removal of the transmembrane and cytoplasmic domains stabilized even the most highly unstable Env. Understanding the causes of instability and taking preemptive actions will facilitate the development of rMVA and other poxviruses as human and veterinary recombinant vaccines.