Potent and stable attenuation of live-HIV-1 by gain of a proteolysis-resistant inhibitor of NF-kappaB (IkappaB-alphaS32/36A) and the implications for vaccine development.
Live-attenuated human immunodeficiency viruses (HIVs) are candidates for Acquired Immunodeficiency Syndrome (AIDS) vaccine. Based on the simian immunodeficiency virus (SIV) model for AIDS, loss-of-function (e.g. deletion of accessory genes such as nef) has been forwarded as a primary approach for creating enfeebled, but replication-competent, HIV-1/SIV. Regrettably, recent evidence suggests that loss-of-function alone is not always sufficient to prevent the emergence of virulent mutants. New strategies that attenuate via mechanisms distinct from loss-of-function are needed for enhancing the safety phenotype of viral genome. Here, we propose gain-of-function to be used simultaneously with loss-of-function as a novel approach for attenuating HIV-1. We have constructed an HIV-1 genome carrying the cDNA of a proteolysis-resistant nuclear factor-kappaB inhibitor (IkappaB-alphaS32/36A) in the nef region. HIV-1 expressing IkappaB-alphaS32/36A down-regulates viral expression and is highly attenuated in both Jurkat and peripheral blood mononuclear cells. We provide formal proof that the phenotypic and attenuating characteristics of IkappaB-alphaS32/36A permit its stable maintenance in a live, replicating HIV-1 despite 180 days of forced ex vivo passaging in tissue culture. As compared with other open-reading frames embedded into HIV/SIV genome, this degree of stability is unprecedented. Thus, IkappaB-alphaS32/36A offers proof-of-principle that artifactually gained functions, when used to attenuate the replication of live HIV-1, can be stable. These findings illustrate gain-of-function as a feasible strategy for developing safer live-attenuated HIVs to be tested as candidates for AIDS vaccine.
Quinto
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I
Dipartimento di Biochimica e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Napoli I-80131, Italy. quinto@adbbm.unina.it
Mallardo
M
M
Baldassarre
F
F
Scala
G
G
Englund
G
G
Jeang
K T
KT
D016915:AIDS Vaccines / Q000276:immunology*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics*; D015536:Down-Regulation; D015967:Gene Expression Regulation, Viral / Q000276:immunology; D005814:Genes, Viral / Q000276:immunology; D015754:Genes, nef; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics* / Q000276:immunology; D006801:Humans; D020672:I-kappa B Proteins; D019169:Jurkat Cells / Q000821:virology; D009000:Monocytes / Q000821:virology; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000235:genetics; D010641:Phenotype; D012367:RNA, Viral / Q000235:genetics; D012692:Serial Passage; D015302:Simian Immunodeficiency Virus / Q000235:genetics; D014162:Transfection; D014613:Vaccines, Attenuated / Q000235:genetics; D014779:Virus Replication
D016915:AIDS Vaccines; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D012367:RNA, Viral; D014613:Vaccines, Attenuated; D000072000:NF-KappaB Inhibitor alpha