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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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Extended Data for Figure 3 (IC80 values)The IC80 values from studies of Figs. 1b, 2a, 2b, and Extended Data Figs. 4–6 are plotted. The number of isolates resistant to 50 μg/ml of the indicated inhibitors are indicated on top. Geometric means are calculated for neutralized isolates and indicated with horizontal lines.
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Figure 11: Extended Data for Figure 3 (IC80 values)The IC80 values from studies of Figs. 1b, 2a, 2b, and Extended Data Figs. 4–6 are plotted. The number of isolates resistant to 50 μg/ml of the indicated inhibitors are indicated on top. Geometric means are calculated for neutralized isolates and indicated with horizontal lines.

Mentions: We further evaluated eCD4-Ig, eCD4-Igmim2, eCD4-IgQ40A,mim2 and the bNAb NIH45-46 using nearly every isolate reported to be resistant to either of the CD4bs antibodies NIH45-46 or 3BNC117 (Extended Data Figs. 4b and 5b). Both eCD4-Ig variants efficiently neutralized all 38 resistant isolates assayed with IC50s ranging from <0.001 μg/ml to 1.453 μg/ml. In contrast, 26 isolates in this panel were confirmed to be resistant to NIH45-46. 29 isolates and 18 isolates have been previously reported resistant to 3BCN117 and VRC01, respectively4,6. Fig. 3 and Extended Data Fig. 7 summarize the neutralization studies compiled from the experiments in Figs. 1 and 2, Extended Data Figs. 4–6, and from previous studies of VRC01 and 3BNC117 against the same isolates4. They show that the geometric mean IC50 and IC80 values of eCD4-Ig and its variants are less than 0.05 μg/ml (500 pM) and 0.2 μg/ml (2 nM), respectively, roughly 3–4 times lower than those of VRC01, NIH45-46, or 3BNC117. Importantly, our lead eCD4-Ig variant, eCD4-Igmim2, neutralized 100% of the isolates assayed at concentrations (IC50 < 1.5 μg/ml; IC80 < 5.2 μg/ml) likely sustainable in humans.


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)

Extended Data for Figure 3 (IC80 values)The IC80 values from studies of Figs. 1b, 2a, 2b, and Extended Data Figs. 4–6 are plotted. The number of isolates resistant to 50 μg/ml of the indicated inhibitors are indicated on top. Geometric means are calculated for neutralized isolates and indicated with horizontal lines.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4352131&req=5

Figure 11: Extended Data for Figure 3 (IC80 values)The IC80 values from studies of Figs. 1b, 2a, 2b, and Extended Data Figs. 4–6 are plotted. The number of isolates resistant to 50 μg/ml of the indicated inhibitors are indicated on top. Geometric means are calculated for neutralized isolates and indicated with horizontal lines.
Mentions: We further evaluated eCD4-Ig, eCD4-Igmim2, eCD4-IgQ40A,mim2 and the bNAb NIH45-46 using nearly every isolate reported to be resistant to either of the CD4bs antibodies NIH45-46 or 3BNC117 (Extended Data Figs. 4b and 5b). Both eCD4-Ig variants efficiently neutralized all 38 resistant isolates assayed with IC50s ranging from <0.001 μg/ml to 1.453 μg/ml. In contrast, 26 isolates in this panel were confirmed to be resistant to NIH45-46. 29 isolates and 18 isolates have been previously reported resistant to 3BCN117 and VRC01, respectively4,6. Fig. 3 and Extended Data Fig. 7 summarize the neutralization studies compiled from the experiments in Figs. 1 and 2, Extended Data Figs. 4–6, and from previous studies of VRC01 and 3BNC117 against the same isolates4. They show that the geometric mean IC50 and IC80 values of eCD4-Ig and its variants are less than 0.05 μg/ml (500 pM) and 0.2 μg/ml (2 nM), respectively, roughly 3–4 times lower than those of VRC01, NIH45-46, or 3BNC117. Importantly, our lead eCD4-Ig variant, eCD4-Igmim2, neutralized 100% of the isolates assayed at concentrations (IC50 < 1.5 μg/ml; IC80 < 5.2 μg/ml) likely sustainable in humans.

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