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Optimal Combinations of Broadly Neutralizing Antibodies for Prevention and Treatment of HIV-1 Clade C Infection.

Wagh K, Bhattacharya T, Williamson C, Robles A, Bayne M, Garrity J, Rist M, Rademeyer C, Yoon H, Lapedes A, Gao H, Greene K, Louder MK, Kong R, Karim SA, Burton DR, Barouch DH, Nussenzweig MC, Mascola JR, Morris L, Montefiori DC, Korber B, Seaman MS - PLoS Pathog. (2016)

Bottom Line: While combinations of bnAbs targeting distinct epitopes on the viral envelope (Env) will likely be required to overcome the extraordinary diversity of HIV-1, a key outstanding question is which bnAbs, and how many, will be needed to achieve optimal clinical benefit.Using this model, we performed a comprehensive and systematic comparison of the predicted neutralizing activity of over 1,600 possible double, triple, and quadruple bnAb combinations.By this set of criteria, triple and quadruple combinations of bnAbs were identified that were significantly more effective than the best double combinations, and further improved the probability of having multiple bnAbs simultaneously active against a given virus, a requirement that may be critical for countering escape in vivo.

View Article: PubMed Central - PubMed

Affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.

ABSTRACT
The identification of a new generation of potent broadly neutralizing HIV-1 antibodies (bnAbs) has generated substantial interest in their potential use for the prevention and/or treatment of HIV-1 infection. While combinations of bnAbs targeting distinct epitopes on the viral envelope (Env) will likely be required to overcome the extraordinary diversity of HIV-1, a key outstanding question is which bnAbs, and how many, will be needed to achieve optimal clinical benefit. We assessed the neutralizing activity of 15 bnAbs targeting four distinct epitopes of Env, including the CD4-binding site (CD4bs), the V1/V2-glycan region, the V3-glycan region, and the gp41 membrane proximal external region (MPER), against a panel of 200 acute/early clade C HIV-1 Env pseudoviruses. A mathematical model was developed that predicted neutralization by a subset of experimentally evaluated bnAb combinations with high accuracy. Using this model, we performed a comprehensive and systematic comparison of the predicted neutralizing activity of over 1,600 possible double, triple, and quadruple bnAb combinations. The most promising bnAb combinations were identified based not only on breadth and potency of neutralization, but also other relevant measures, such as the extent of complete neutralization and instantaneous inhibitory potential (IIP). By this set of criteria, triple and quadruple combinations of bnAbs were identified that were significantly more effective than the best double combinations, and further improved the probability of having multiple bnAbs simultaneously active against a given virus, a requirement that may be critical for countering escape in vivo. These results provide a rationale for advancing bnAb combinations with the best in vitro predictors of success into clinical trials for both the prevention and treatment of HIV-1 infection.

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Neutralization activity of bnAbs against clade C virus panel.Potency-breadth curves are presented for both IC50 (A) and IC80 (B) titers. BnAbs are color coded and grouped by target epitopes. Bold lines indicate bnAbs that were best in class for V2-glycan (V2g), V3-glycan (V3g), CD4bs, and MPER epitopes. Dashed vertical lines indicated the lowest and highest concentration tested. Neutralization data are also presented as scatter plots of IC50 (C) and IC80 (D) titers in which each virus is represented by an individual dot. The highest concentration tested for each bnAb and the percentage of viruses neutralized are indicated. Solid bars represent median titers. Heat maps of IC50 (E) and IC80 (F) were generated using the Heatmap tool on the Los Alamos HIV Database. In the heatmaps, rows represent viruses, and columns represent bnAbs. The darker hues indicate more potent neutralization, and blue (for contrast) indicates the virus had IC50 or IC80 above threshold, unable to reach this level of neutralization at the highest concentration of bnAb tested. The order of viruses is same in panels E and F.
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ppat.1005520.g001: Neutralization activity of bnAbs against clade C virus panel.Potency-breadth curves are presented for both IC50 (A) and IC80 (B) titers. BnAbs are color coded and grouped by target epitopes. Bold lines indicate bnAbs that were best in class for V2-glycan (V2g), V3-glycan (V3g), CD4bs, and MPER epitopes. Dashed vertical lines indicated the lowest and highest concentration tested. Neutralization data are also presented as scatter plots of IC50 (C) and IC80 (D) titers in which each virus is represented by an individual dot. The highest concentration tested for each bnAb and the percentage of viruses neutralized are indicated. Solid bars represent median titers. Heat maps of IC50 (E) and IC80 (F) were generated using the Heatmap tool on the Los Alamos HIV Database. In the heatmaps, rows represent viruses, and columns represent bnAbs. The darker hues indicate more potent neutralization, and blue (for contrast) indicates the virus had IC50 or IC80 above threshold, unable to reach this level of neutralization at the highest concentration of bnAb tested. The order of viruses is same in panels E and F.

Mentions: A panel of bnAbs targeting HIV-1 Env was used to assess and compare the breadth and potency of neutralization against acute/early clade C Envs. Fifteen bnAbs were selected that target four distinct epitope regions: the CD4 binding site (CD4bs: 3BNC117, VRC01, VRC07, VRC07-523, VRC13) [11, 19, 23, 69, 70], the V3-glycan supersite (V3g: 10–1074, 10-1074V, PGT121, PGT128) [9, 17], the V1/V2-glycan site (V2g: PG9, PGT145, PGDM1400, CAP256-VRC26.08, CAP256-VRC26.25) [9, 10, 12, 20, 32], and the gp41 MPER epitope (10E8) [15]. BnAbs were tested against a panel of 200 clade C HIV-1 Env pseudoviruses using the validated luciferase-based TZM-bl assay. This virus panel consists of viruses isolated from individuals in the acute/early stages of infection from five southern African countries, including South Africa, Tanzania, Malawi, Zambia, and Botswana. Serial dilutions of individual bnAbs were tested against each virus using a starting concentration that ranged from 10–50 μg/ml, depending on sample availability at the time of testing. Neutralizing activities were evaluated using potency-breadth curves (the percentage of viruses neutralized versus an IC50 or IC80 cutoff, Fig 1A and 1B), scatter plots (Fig 1C and 1D) and heatmaps (Fig 1E and 1F). The 5 bnAbs targeting the V1/V2-glycan region neutralized between 67–75% of viruses with positive IC50 titers, and the 4 bnAbs targeting V3-glycan neutralized 54–68%. When positive, these glycan-dependent bnAbs were strikingly potent. Using the more stringent IC80 measure, median IC80 titers ranged from 0.003–1.274 μg/ml for V1/V2-glycan and 0.073–0.203 μg/ml for V3-glycan bnAbs (Table A in S1 Text). CD4bs bnAbs tended to exhibit greater breadth (71–96% at IC50), but were generally less potent than V1/V2-glycan or V3-glycan antibodies (median IC80 titers 0.30–1.58 μg/ml). The MPER directed bnAb 10E8 exhibited lower overall potency (median IC80 3.399 μg/ml), yet had exceptional IC50 breadth, neutralizing 98% of viruses. Even the most resistant isolates were sensitive to at least 3 bnAbs, which most often targeted the CD4bs or MPER. Overall, clear differences in potency and/or breadth were observed among bnAbs of the same class (defined here as bnAbs that target the same epitope region). Based on IC50 and IC80 titers, best-in-class bnAbs were CAP256-VRC26.25 (V2-glycan), 10-1074V (V3-glycan), VRC07-523 (CD4bs), and 10E8 (MPER).


Optimal Combinations of Broadly Neutralizing Antibodies for Prevention and Treatment of HIV-1 Clade C Infection.

Wagh K, Bhattacharya T, Williamson C, Robles A, Bayne M, Garrity J, Rist M, Rademeyer C, Yoon H, Lapedes A, Gao H, Greene K, Louder MK, Kong R, Karim SA, Burton DR, Barouch DH, Nussenzweig MC, Mascola JR, Morris L, Montefiori DC, Korber B, Seaman MS - PLoS Pathog. (2016)

Neutralization activity of bnAbs against clade C virus panel.Potency-breadth curves are presented for both IC50 (A) and IC80 (B) titers. BnAbs are color coded and grouped by target epitopes. Bold lines indicate bnAbs that were best in class for V2-glycan (V2g), V3-glycan (V3g), CD4bs, and MPER epitopes. Dashed vertical lines indicated the lowest and highest concentration tested. Neutralization data are also presented as scatter plots of IC50 (C) and IC80 (D) titers in which each virus is represented by an individual dot. The highest concentration tested for each bnAb and the percentage of viruses neutralized are indicated. Solid bars represent median titers. Heat maps of IC50 (E) and IC80 (F) were generated using the Heatmap tool on the Los Alamos HIV Database. In the heatmaps, rows represent viruses, and columns represent bnAbs. The darker hues indicate more potent neutralization, and blue (for contrast) indicates the virus had IC50 or IC80 above threshold, unable to reach this level of neutralization at the highest concentration of bnAb tested. The order of viruses is same in panels E and F.
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ppat.1005520.g001: Neutralization activity of bnAbs against clade C virus panel.Potency-breadth curves are presented for both IC50 (A) and IC80 (B) titers. BnAbs are color coded and grouped by target epitopes. Bold lines indicate bnAbs that were best in class for V2-glycan (V2g), V3-glycan (V3g), CD4bs, and MPER epitopes. Dashed vertical lines indicated the lowest and highest concentration tested. Neutralization data are also presented as scatter plots of IC50 (C) and IC80 (D) titers in which each virus is represented by an individual dot. The highest concentration tested for each bnAb and the percentage of viruses neutralized are indicated. Solid bars represent median titers. Heat maps of IC50 (E) and IC80 (F) were generated using the Heatmap tool on the Los Alamos HIV Database. In the heatmaps, rows represent viruses, and columns represent bnAbs. The darker hues indicate more potent neutralization, and blue (for contrast) indicates the virus had IC50 or IC80 above threshold, unable to reach this level of neutralization at the highest concentration of bnAb tested. The order of viruses is same in panels E and F.
Mentions: A panel of bnAbs targeting HIV-1 Env was used to assess and compare the breadth and potency of neutralization against acute/early clade C Envs. Fifteen bnAbs were selected that target four distinct epitope regions: the CD4 binding site (CD4bs: 3BNC117, VRC01, VRC07, VRC07-523, VRC13) [11, 19, 23, 69, 70], the V3-glycan supersite (V3g: 10–1074, 10-1074V, PGT121, PGT128) [9, 17], the V1/V2-glycan site (V2g: PG9, PGT145, PGDM1400, CAP256-VRC26.08, CAP256-VRC26.25) [9, 10, 12, 20, 32], and the gp41 MPER epitope (10E8) [15]. BnAbs were tested against a panel of 200 clade C HIV-1 Env pseudoviruses using the validated luciferase-based TZM-bl assay. This virus panel consists of viruses isolated from individuals in the acute/early stages of infection from five southern African countries, including South Africa, Tanzania, Malawi, Zambia, and Botswana. Serial dilutions of individual bnAbs were tested against each virus using a starting concentration that ranged from 10–50 μg/ml, depending on sample availability at the time of testing. Neutralizing activities were evaluated using potency-breadth curves (the percentage of viruses neutralized versus an IC50 or IC80 cutoff, Fig 1A and 1B), scatter plots (Fig 1C and 1D) and heatmaps (Fig 1E and 1F). The 5 bnAbs targeting the V1/V2-glycan region neutralized between 67–75% of viruses with positive IC50 titers, and the 4 bnAbs targeting V3-glycan neutralized 54–68%. When positive, these glycan-dependent bnAbs were strikingly potent. Using the more stringent IC80 measure, median IC80 titers ranged from 0.003–1.274 μg/ml for V1/V2-glycan and 0.073–0.203 μg/ml for V3-glycan bnAbs (Table A in S1 Text). CD4bs bnAbs tended to exhibit greater breadth (71–96% at IC50), but were generally less potent than V1/V2-glycan or V3-glycan antibodies (median IC80 titers 0.30–1.58 μg/ml). The MPER directed bnAb 10E8 exhibited lower overall potency (median IC80 3.399 μg/ml), yet had exceptional IC50 breadth, neutralizing 98% of viruses. Even the most resistant isolates were sensitive to at least 3 bnAbs, which most often targeted the CD4bs or MPER. Overall, clear differences in potency and/or breadth were observed among bnAbs of the same class (defined here as bnAbs that target the same epitope region). Based on IC50 and IC80 titers, best-in-class bnAbs were CAP256-VRC26.25 (V2-glycan), 10-1074V (V3-glycan), VRC07-523 (CD4bs), and 10E8 (MPER).

Bottom Line: While combinations of bnAbs targeting distinct epitopes on the viral envelope (Env) will likely be required to overcome the extraordinary diversity of HIV-1, a key outstanding question is which bnAbs, and how many, will be needed to achieve optimal clinical benefit.Using this model, we performed a comprehensive and systematic comparison of the predicted neutralizing activity of over 1,600 possible double, triple, and quadruple bnAb combinations.By this set of criteria, triple and quadruple combinations of bnAbs were identified that were significantly more effective than the best double combinations, and further improved the probability of having multiple bnAbs simultaneously active against a given virus, a requirement that may be critical for countering escape in vivo.

View Article: PubMed Central - PubMed

Affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.

ABSTRACT
The identification of a new generation of potent broadly neutralizing HIV-1 antibodies (bnAbs) has generated substantial interest in their potential use for the prevention and/or treatment of HIV-1 infection. While combinations of bnAbs targeting distinct epitopes on the viral envelope (Env) will likely be required to overcome the extraordinary diversity of HIV-1, a key outstanding question is which bnAbs, and how many, will be needed to achieve optimal clinical benefit. We assessed the neutralizing activity of 15 bnAbs targeting four distinct epitopes of Env, including the CD4-binding site (CD4bs), the V1/V2-glycan region, the V3-glycan region, and the gp41 membrane proximal external region (MPER), against a panel of 200 acute/early clade C HIV-1 Env pseudoviruses. A mathematical model was developed that predicted neutralization by a subset of experimentally evaluated bnAb combinations with high accuracy. Using this model, we performed a comprehensive and systematic comparison of the predicted neutralizing activity of over 1,600 possible double, triple, and quadruple bnAb combinations. The most promising bnAb combinations were identified based not only on breadth and potency of neutralization, but also other relevant measures, such as the extent of complete neutralization and instantaneous inhibitory potential (IIP). By this set of criteria, triple and quadruple combinations of bnAbs were identified that were significantly more effective than the best double combinations, and further improved the probability of having multiple bnAbs simultaneously active against a given virus, a requirement that may be critical for countering escape in vivo. These results provide a rationale for advancing bnAb combinations with the best in vitro predictors of success into clinical trials for both the prevention and treatment of HIV-1 infection.

Show MeSH
Related in: MedlinePlus