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AAV-expressed eCD4-Ig provides durable protection from multiple SHIV challenges.

Gardner MR, Kattenhorn LM, Kondur HR, von Schaewen M, Dorfman T, Chiang JJ, Haworth KG, Decker JM, Alpert MD, Bailey CC, Neale ES, Fellinger CH, Joshi VR, Fuchs SP, Martinez-Navio JM, Quinlan BD, Yao AY, Mouquet H, Gorman J, Zhang B, Poignard P, Nussenzweig MC, Burton DR, Kwong PD, Piatak M, Lifson JD, Gao G, Desrosiers RC, Evans DT, Hahn BH, Ploss A, Cannon PM, Seaman MS, Farzan M - Nature (2015)

Bottom Line: Rhesus macaques inoculated with an AAV vector stably expressed 17-77 μg ml(-1) of fully functional rhesus eCD4-Ig for more than 40 weeks, and these macaques were protected from several infectious challenges with SHIV-AD8.Rhesus eCD4-Ig was also markedly less immunogenic than rhesus forms of four well-characterized bNAbs.Our data suggest that AAV-delivered eCD4-Ig can function like an effective HIV-1 vaccine.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, The Scripps Research Institute, Jupiter, Florida 33458, USA.

ABSTRACT
Long-term in vivo expression of a broad and potent entry inhibitor could circumvent the need for a conventional vaccine for HIV-1. Adeno-associated virus (AAV) vectors can stably express HIV-1 broadly neutralizing antibodies (bNAbs). However, even the best bNAbs neutralize 10-50% of HIV-1 isolates inefficiently (80% inhibitory concentration (IC80) > 5 μg ml(-1)), suggesting that high concentrations of these antibodies would be necessary to achieve general protection. Here we show that eCD4-Ig, a fusion of CD4-Ig with a small CCR5-mimetic sulfopeptide, binds avidly and cooperatively to the HIV-1 envelope glycoprotein (Env) and is more potent than the best bNAbs (geometric mean half-maximum inhibitory concentration (IC50) < 0.05 μg ml(-1)). Because eCD4-Ig binds only conserved regions of Env, it is also much broader than any bNAb. For example, eCD4-Ig efficiently neutralized 100% of a diverse panel of neutralization-resistant HIV-1, HIV-2 and simian immunodeficiency virus isolates, including a comprehensive set of isolates resistant to the CD4-binding site bNAbs VRC01, NIH45-46 and 3BNC117. Rhesus macaques inoculated with an AAV vector stably expressed 17-77 μg ml(-1) of fully functional rhesus eCD4-Ig for more than 40 weeks, and these macaques were protected from several infectious challenges with SHIV-AD8. Rhesus eCD4-Ig was also markedly less immunogenic than rhesus forms of four well-characterized bNAbs. Our data suggest that AAV-delivered eCD4-Ig can function like an effective HIV-1 vaccine.

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IC50 values of eCD4-Ig variants against neutralization-resistant isolates.a, The IC50 values (μg/mL) of CD4-Ig, eCD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A (Q40A), and eCD4-IgQ40A,mim2 (Q40A,mim2) against 24 HIV-1 and SIV isolates selected for their neutralization resistance are shown. The clade and tier of each isolate is listed. HIV-1 pseudotyped with the indicted envelope glycoprotein was incubated in triplicate with TZM-bl cells and varying concentrations of CD4-Ig or eCD4-Ig variant. Luciferase activity was determined two days post-infection. ‘Fold’ indicates the ratio of the IC50 value of CD4-Ig to the geometric mean of the IC50 values of the assayed eCD4-Ig variants. The geometric mean of eCD4-Ig variants and the CD4bs antibodies 3BCN117, NIH45-46, and VRC01 calculated from values reported in Huang et al. and Sheid et al.4,6 are shown in the two rightmost columns. b, Neutralization studies similar to those in (a) except that the IC50 values of CD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A,mim2 (Q40A,mim2) and NIH45-46 were determined for a panel of 40 viral isolates selected for their resistance to the CD4bs bNAbs 3BNC117 and NIH45-46. IC50 values of the CD4bs antibodies VRC01 and 3BNC117 listed in the two rightmost columns were reported in Huang et al. and Scheid et al.4,6
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Figure 8: IC50 values of eCD4-Ig variants against neutralization-resistant isolates.a, The IC50 values (μg/mL) of CD4-Ig, eCD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A (Q40A), and eCD4-IgQ40A,mim2 (Q40A,mim2) against 24 HIV-1 and SIV isolates selected for their neutralization resistance are shown. The clade and tier of each isolate is listed. HIV-1 pseudotyped with the indicted envelope glycoprotein was incubated in triplicate with TZM-bl cells and varying concentrations of CD4-Ig or eCD4-Ig variant. Luciferase activity was determined two days post-infection. ‘Fold’ indicates the ratio of the IC50 value of CD4-Ig to the geometric mean of the IC50 values of the assayed eCD4-Ig variants. The geometric mean of eCD4-Ig variants and the CD4bs antibodies 3BCN117, NIH45-46, and VRC01 calculated from values reported in Huang et al. and Sheid et al.4,6 are shown in the two rightmost columns. b, Neutralization studies similar to those in (a) except that the IC50 values of CD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A,mim2 (Q40A,mim2) and NIH45-46 were determined for a panel of 40 viral isolates selected for their resistance to the CD4bs bNAbs 3BNC117 and NIH45-46. IC50 values of the CD4bs antibodies VRC01 and 3BNC117 listed in the two rightmost columns were reported in Huang et al. and Scheid et al.4,6

Mentions: We then characterized the ability of eCD4-Ig to neutralize a diverse panel of neutralization resistant tier 2 and 3 viruses25 (Extended Data Figs. 4a and 5a). In parallel, we assayed three additional eCD4-Ig variants. In the first, eCD4-Igmim2, CCR5mim1 was replaced by CCR5mim2, which differs from CCR5mim1 by single alanine to tyrosine substitution22. We also introduced a previously characterized glutamine 40 to alanine mutation into CD4 domain 1 of eCD4-Ig (eCD4-IgQ40A)16. Both mutations were combined in a final variant (eCD4-IgQ40A,mim2). eCD4-Ig and these variants substantially outperformed CD4-Ig for every virus in the panel, typically improving neutralization potency by 20 to >200-fold. Underscoring its breadth, eCD4-Ig neutralized SIVmac251 33 times more efficiently than CD4-Ig. In general, the more neutralization resistant a virus, the better eCD4-Ig and its variants performed relative to CD4-Ig. In most cases, replacement of CCR5mim1 with CCR5mim2 modestly improved neutralization. Similarly, the Q40A mutation also improved neutralization of most HIV-1 isolates, but not of SIVmac251.


AAV-expressed eCD4-Ig provides durable protection from multiple SHIV challenges.

Gardner MR, Kattenhorn LM, Kondur HR, von Schaewen M, Dorfman T, Chiang JJ, Haworth KG, Decker JM, Alpert MD, Bailey CC, Neale ES, Fellinger CH, Joshi VR, Fuchs SP, Martinez-Navio JM, Quinlan BD, Yao AY, Mouquet H, Gorman J, Zhang B, Poignard P, Nussenzweig MC, Burton DR, Kwong PD, Piatak M, Lifson JD, Gao G, Desrosiers RC, Evans DT, Hahn BH, Ploss A, Cannon PM, Seaman MS, Farzan M - Nature (2015)

IC50 values of eCD4-Ig variants against neutralization-resistant isolates.a, The IC50 values (μg/mL) of CD4-Ig, eCD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A (Q40A), and eCD4-IgQ40A,mim2 (Q40A,mim2) against 24 HIV-1 and SIV isolates selected for their neutralization resistance are shown. The clade and tier of each isolate is listed. HIV-1 pseudotyped with the indicted envelope glycoprotein was incubated in triplicate with TZM-bl cells and varying concentrations of CD4-Ig or eCD4-Ig variant. Luciferase activity was determined two days post-infection. ‘Fold’ indicates the ratio of the IC50 value of CD4-Ig to the geometric mean of the IC50 values of the assayed eCD4-Ig variants. The geometric mean of eCD4-Ig variants and the CD4bs antibodies 3BCN117, NIH45-46, and VRC01 calculated from values reported in Huang et al. and Sheid et al.4,6 are shown in the two rightmost columns. b, Neutralization studies similar to those in (a) except that the IC50 values of CD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A,mim2 (Q40A,mim2) and NIH45-46 were determined for a panel of 40 viral isolates selected for their resistance to the CD4bs bNAbs 3BNC117 and NIH45-46. IC50 values of the CD4bs antibodies VRC01 and 3BNC117 listed in the two rightmost columns were reported in Huang et al. and Scheid et al.4,6
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Figure 8: IC50 values of eCD4-Ig variants against neutralization-resistant isolates.a, The IC50 values (μg/mL) of CD4-Ig, eCD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A (Q40A), and eCD4-IgQ40A,mim2 (Q40A,mim2) against 24 HIV-1 and SIV isolates selected for their neutralization resistance are shown. The clade and tier of each isolate is listed. HIV-1 pseudotyped with the indicted envelope glycoprotein was incubated in triplicate with TZM-bl cells and varying concentrations of CD4-Ig or eCD4-Ig variant. Luciferase activity was determined two days post-infection. ‘Fold’ indicates the ratio of the IC50 value of CD4-Ig to the geometric mean of the IC50 values of the assayed eCD4-Ig variants. The geometric mean of eCD4-Ig variants and the CD4bs antibodies 3BCN117, NIH45-46, and VRC01 calculated from values reported in Huang et al. and Sheid et al.4,6 are shown in the two rightmost columns. b, Neutralization studies similar to those in (a) except that the IC50 values of CD4-Ig, eCD4-Igmim2 (mim2), eCD4-IgQ40A,mim2 (Q40A,mim2) and NIH45-46 were determined for a panel of 40 viral isolates selected for their resistance to the CD4bs bNAbs 3BNC117 and NIH45-46. IC50 values of the CD4bs antibodies VRC01 and 3BNC117 listed in the two rightmost columns were reported in Huang et al. and Scheid et al.4,6
Mentions: We then characterized the ability of eCD4-Ig to neutralize a diverse panel of neutralization resistant tier 2 and 3 viruses25 (Extended Data Figs. 4a and 5a). In parallel, we assayed three additional eCD4-Ig variants. In the first, eCD4-Igmim2, CCR5mim1 was replaced by CCR5mim2, which differs from CCR5mim1 by single alanine to tyrosine substitution22. We also introduced a previously characterized glutamine 40 to alanine mutation into CD4 domain 1 of eCD4-Ig (eCD4-IgQ40A)16. Both mutations were combined in a final variant (eCD4-IgQ40A,mim2). eCD4-Ig and these variants substantially outperformed CD4-Ig for every virus in the panel, typically improving neutralization potency by 20 to >200-fold. Underscoring its breadth, eCD4-Ig neutralized SIVmac251 33 times more efficiently than CD4-Ig. In general, the more neutralization resistant a virus, the better eCD4-Ig and its variants performed relative to CD4-Ig. In most cases, replacement of CCR5mim1 with CCR5mim2 modestly improved neutralization. Similarly, the Q40A mutation also improved neutralization of most HIV-1 isolates, but not of SIVmac251.

Bottom Line: Rhesus macaques inoculated with an AAV vector stably expressed 17-77 μg ml(-1) of fully functional rhesus eCD4-Ig for more than 40 weeks, and these macaques were protected from several infectious challenges with SHIV-AD8.Rhesus eCD4-Ig was also markedly less immunogenic than rhesus forms of four well-characterized bNAbs.Our data suggest that AAV-delivered eCD4-Ig can function like an effective HIV-1 vaccine.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, The Scripps Research Institute, Jupiter, Florida 33458, USA.

ABSTRACT
Long-term in vivo expression of a broad and potent entry inhibitor could circumvent the need for a conventional vaccine for HIV-1. Adeno-associated virus (AAV) vectors can stably express HIV-1 broadly neutralizing antibodies (bNAbs). However, even the best bNAbs neutralize 10-50% of HIV-1 isolates inefficiently (80% inhibitory concentration (IC80) > 5 μg ml(-1)), suggesting that high concentrations of these antibodies would be necessary to achieve general protection. Here we show that eCD4-Ig, a fusion of CD4-Ig with a small CCR5-mimetic sulfopeptide, binds avidly and cooperatively to the HIV-1 envelope glycoprotein (Env) and is more potent than the best bNAbs (geometric mean half-maximum inhibitory concentration (IC50) < 0.05 μg ml(-1)). Because eCD4-Ig binds only conserved regions of Env, it is also much broader than any bNAb. For example, eCD4-Ig efficiently neutralized 100% of a diverse panel of neutralization-resistant HIV-1, HIV-2 and simian immunodeficiency virus isolates, including a comprehensive set of isolates resistant to the CD4-binding site bNAbs VRC01, NIH45-46 and 3BNC117. Rhesus macaques inoculated with an AAV vector stably expressed 17-77 μg ml(-1) of fully functional rhesus eCD4-Ig for more than 40 weeks, and these macaques were protected from several infectious challenges with SHIV-AD8. Rhesus eCD4-Ig was also markedly less immunogenic than rhesus forms of four well-characterized bNAbs. Our data suggest that AAV-delivered eCD4-Ig can function like an effective HIV-1 vaccine.

Show MeSH
Related in: MedlinePlus