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Association of enhanced HIV-1 neutralization by a single Y681H substitution in gp41 with increased gp120-CD4 interaction and macrophage infectivity.

Ringe R, Bhattacharya J - PLoS ONE (2012)

Bottom Line: In the present study, we found that presence of a naturally occurring H681 in gp41 membrane proximal external region (MPER) of a clade C envelope (Env) obtained from a recently infected Indian patient conferred increased sensitivity to autologous and heterologous plasma antibodies.Furthermore, Env-pseudotyped viruses expressing H681 showed increased sensitivity to soluble CD4, b12 and 4E10 monoclonal antibodies both in related and unrelated Envs and was corroborated with increased Env susceptibility and binding to cellular CD4 as well as with prolonged exposure of MPER epitopes.In summary, our data indicate that Y681H substitution exposes neutralizing epitopes in CD4bs and MPER towards comprehensive interference in HIV-1 entry.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Virology, National AIDS Research Institute, Indian Council of Medical Research, Bhosari, Pune, India.

ABSTRACT
HIV-1 variants that show unusual sensitivity to autologous antibodies due to presence of critical neutralization signatures would likely contribute towards rational envelope based HIV-1 vaccine design. In the present study, we found that presence of a naturally occurring H681 in gp41 membrane proximal external region (MPER) of a clade C envelope (Env) obtained from a recently infected Indian patient conferred increased sensitivity to autologous and heterologous plasma antibodies. Furthermore, Env-pseudotyped viruses expressing H681 showed increased sensitivity to soluble CD4, b12 and 4E10 monoclonal antibodies both in related and unrelated Envs and was corroborated with increased Env susceptibility and binding to cellular CD4 as well as with prolonged exposure of MPER epitopes. The increased gp120-CD4 interaction was further associated with relative exposure of CD4-induced epitopes and macrophage infectivity. In summary, our data indicate that Y681H substitution exposes neutralizing epitopes in CD4bs and MPER towards comprehensive interference in HIV-1 entry.

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Effect of Y681H substitution on exposure of neutralizing epitopes in gp41 MPER.A. Neutralization sensitivity of Env-pseudotyped viruses expressing Y681 and H681 were tested against 4E10 MAb in TZM-bl cells. Percent neutralization on Y-axis against serial dilutions of 4E10 indicated on X-axis shows H681 conferring increased Env sensitivity to 4E10 MAb (and also T20; see Figure S1 and Table 1). The neutralization assays were done in duplicate in more than three independent experiments. VC stands for virus control where antibody was not added. B. Time course of 4E10 MAb neutralization of Envs. 4E10 was added in warm condition (37°C) at different time points in TZM-bl cells which were pre-adsorbed with Env pseudotyped virus in cold condition. The percent infection is plotted on Y-axis against various time points of 4E10 addition given on X-axis. No 4E10 indicates infection of TZM-bl cells in absence of 4E10 MAb and hence serves as virus control. Note that 4E10 could neutralize 4.J2 (H681) by 50% up to 6 min as opposed to 1 min for 4.J2 (Y681). TND S669 that was earlier reported [44] for enhanced exposure of neutralizing epitopes in MPER was used as positive control.
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pone-0037157-g003: Effect of Y681H substitution on exposure of neutralizing epitopes in gp41 MPER.A. Neutralization sensitivity of Env-pseudotyped viruses expressing Y681 and H681 were tested against 4E10 MAb in TZM-bl cells. Percent neutralization on Y-axis against serial dilutions of 4E10 indicated on X-axis shows H681 conferring increased Env sensitivity to 4E10 MAb (and also T20; see Figure S1 and Table 1). The neutralization assays were done in duplicate in more than three independent experiments. VC stands for virus control where antibody was not added. B. Time course of 4E10 MAb neutralization of Envs. 4E10 was added in warm condition (37°C) at different time points in TZM-bl cells which were pre-adsorbed with Env pseudotyped virus in cold condition. The percent infection is plotted on Y-axis against various time points of 4E10 addition given on X-axis. No 4E10 indicates infection of TZM-bl cells in absence of 4E10 MAb and hence serves as virus control. Note that 4E10 could neutralize 4.J2 (H681) by 50% up to 6 min as opposed to 1 min for 4.J2 (Y681). TND S669 that was earlier reported [44] for enhanced exposure of neutralizing epitopes in MPER was used as positive control.

Mentions: Since H681 was located in MPER, to further examine if resistance to autologous neutralization conferred by H681Y was due to its effect on MPER, we tested the sensitivity of pseudoviruses carrying 4.J2 (H681) and 4.J2 (Y681) Envs to 4E10 MAb. We did not test the sensitivities of these Envs to 2F5 as they were found to be resistant to 2F5 because of lack of minimum DKW motif for 2F5 recognition [46]. As shown in Figure 3A, we found that while 4.J2 (N668S) did not alter 4E10 sensitivity, H681Y conferred 4E10 resistance by greater than 16-folds. Enhancement of Env sensitivity to 2F5 was also found with unrelated Envs with Y681H substitutions (Table 1), although it was not as dramatic as 4E10. Our data indicated that presence of H681 modulated Env conformation at MPER and increased neutralization by antibodies targeting this region.


Association of enhanced HIV-1 neutralization by a single Y681H substitution in gp41 with increased gp120-CD4 interaction and macrophage infectivity.

Ringe R, Bhattacharya J - PLoS ONE (2012)

Effect of Y681H substitution on exposure of neutralizing epitopes in gp41 MPER.A. Neutralization sensitivity of Env-pseudotyped viruses expressing Y681 and H681 were tested against 4E10 MAb in TZM-bl cells. Percent neutralization on Y-axis against serial dilutions of 4E10 indicated on X-axis shows H681 conferring increased Env sensitivity to 4E10 MAb (and also T20; see Figure S1 and Table 1). The neutralization assays were done in duplicate in more than three independent experiments. VC stands for virus control where antibody was not added. B. Time course of 4E10 MAb neutralization of Envs. 4E10 was added in warm condition (37°C) at different time points in TZM-bl cells which were pre-adsorbed with Env pseudotyped virus in cold condition. The percent infection is plotted on Y-axis against various time points of 4E10 addition given on X-axis. No 4E10 indicates infection of TZM-bl cells in absence of 4E10 MAb and hence serves as virus control. Note that 4E10 could neutralize 4.J2 (H681) by 50% up to 6 min as opposed to 1 min for 4.J2 (Y681). TND S669 that was earlier reported [44] for enhanced exposure of neutralizing epitopes in MPER was used as positive control.
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Related In: Results  -  Collection

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pone-0037157-g003: Effect of Y681H substitution on exposure of neutralizing epitopes in gp41 MPER.A. Neutralization sensitivity of Env-pseudotyped viruses expressing Y681 and H681 were tested against 4E10 MAb in TZM-bl cells. Percent neutralization on Y-axis against serial dilutions of 4E10 indicated on X-axis shows H681 conferring increased Env sensitivity to 4E10 MAb (and also T20; see Figure S1 and Table 1). The neutralization assays were done in duplicate in more than three independent experiments. VC stands for virus control where antibody was not added. B. Time course of 4E10 MAb neutralization of Envs. 4E10 was added in warm condition (37°C) at different time points in TZM-bl cells which were pre-adsorbed with Env pseudotyped virus in cold condition. The percent infection is plotted on Y-axis against various time points of 4E10 addition given on X-axis. No 4E10 indicates infection of TZM-bl cells in absence of 4E10 MAb and hence serves as virus control. Note that 4E10 could neutralize 4.J2 (H681) by 50% up to 6 min as opposed to 1 min for 4.J2 (Y681). TND S669 that was earlier reported [44] for enhanced exposure of neutralizing epitopes in MPER was used as positive control.
Mentions: Since H681 was located in MPER, to further examine if resistance to autologous neutralization conferred by H681Y was due to its effect on MPER, we tested the sensitivity of pseudoviruses carrying 4.J2 (H681) and 4.J2 (Y681) Envs to 4E10 MAb. We did not test the sensitivities of these Envs to 2F5 as they were found to be resistant to 2F5 because of lack of minimum DKW motif for 2F5 recognition [46]. As shown in Figure 3A, we found that while 4.J2 (N668S) did not alter 4E10 sensitivity, H681Y conferred 4E10 resistance by greater than 16-folds. Enhancement of Env sensitivity to 2F5 was also found with unrelated Envs with Y681H substitutions (Table 1), although it was not as dramatic as 4E10. Our data indicated that presence of H681 modulated Env conformation at MPER and increased neutralization by antibodies targeting this region.

Bottom Line: In the present study, we found that presence of a naturally occurring H681 in gp41 membrane proximal external region (MPER) of a clade C envelope (Env) obtained from a recently infected Indian patient conferred increased sensitivity to autologous and heterologous plasma antibodies.Furthermore, Env-pseudotyped viruses expressing H681 showed increased sensitivity to soluble CD4, b12 and 4E10 monoclonal antibodies both in related and unrelated Envs and was corroborated with increased Env susceptibility and binding to cellular CD4 as well as with prolonged exposure of MPER epitopes.In summary, our data indicate that Y681H substitution exposes neutralizing epitopes in CD4bs and MPER towards comprehensive interference in HIV-1 entry.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Virology, National AIDS Research Institute, Indian Council of Medical Research, Bhosari, Pune, India.

ABSTRACT
HIV-1 variants that show unusual sensitivity to autologous antibodies due to presence of critical neutralization signatures would likely contribute towards rational envelope based HIV-1 vaccine design. In the present study, we found that presence of a naturally occurring H681 in gp41 membrane proximal external region (MPER) of a clade C envelope (Env) obtained from a recently infected Indian patient conferred increased sensitivity to autologous and heterologous plasma antibodies. Furthermore, Env-pseudotyped viruses expressing H681 showed increased sensitivity to soluble CD4, b12 and 4E10 monoclonal antibodies both in related and unrelated Envs and was corroborated with increased Env susceptibility and binding to cellular CD4 as well as with prolonged exposure of MPER epitopes. The increased gp120-CD4 interaction was further associated with relative exposure of CD4-induced epitopes and macrophage infectivity. In summary, our data indicate that Y681H substitution exposes neutralizing epitopes in CD4bs and MPER towards comprehensive interference in HIV-1 entry.

Show MeSH
Related in: MedlinePlus