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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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Construction of chimeric envelopes.Chimeric Envs were constructed by swapping of gp120 and gp41 between sensitive (4.J2) and resistant (4.J22) patient Envs using NotI, BbvCI and HindIII restriction enzymes. The ID50 values of pseudotyped viruses carrying 4.J2, 4.J22 and 4.J27 Envs to autologous plasma reported earlier [46] were shown on top; highlighted column represents ID50 of Env-pseudotyped viruses to contemporaneous plasma at the base line.
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pone-0037157-g001: Construction of chimeric envelopes.Chimeric Envs were constructed by swapping of gp120 and gp41 between sensitive (4.J2) and resistant (4.J22) patient Envs using NotI, BbvCI and HindIII restriction enzymes. The ID50 values of pseudotyped viruses carrying 4.J2, 4.J22 and 4.J27 Envs to autologous plasma reported earlier [46] were shown on top; highlighted column represents ID50 of Env-pseudotyped viruses to contemporaneous plasma at the base line.

Mentions: We previously described [46] two clade C Env clones 4.J2 and 4.J22 obtained from a recently infected Indian patient at the baseline (at the same time point) which differed in their sensitivities to autologous plasma antibodies (ID50 of 4.J2 = 1∶540 against ID50 of 4.J22<100) (Figure 1A). The Env clones obtained were within one year of infection as determined by detuned ELISA as described earlier [46]. Sequence comparison between these two Envs revealed differences of altogether six residues in gp160, two in V1V2 domain (at positions 148 and 174 respectively) of gp120 and four in gp41 (Figure 1B). Out of the four residues that differed between these two Envs in gp41 domain, two were in the MPER region at positions 668 and 681, while the two others were at positions 551 and 839. We first investigated domains in Env that modulated sensitivity to contemporaneous autologous plasma by constructing Env chimeras between 4.J2 and 4.J22. Pseudotyped viruses carrying chimeric Env constructs were tested for their neutralization sensitivity to autologous contemporaneous plasma antibodies. As shown in Figure 2, as opposed to the wild type, 4.J2 containing gp41 grafted from 4.J22 conferred resistance while 4.J22 containing gp41 from 4.J2 became sensitive to autologous antibodies, indicating that gp41 in these Envs conferred altered sensitivities to autologous plasma antibodies in this patient. Since residues at positions 668 and 681 in these Envs were within MPER, a region of effective target of neutralizing antibodies, and in very close proximities to motifs that are targets of 2F5 and 4E10, we substituted N668S and H681Y (668S and 681Y were present in resistant Env 4.J22) in the sensitive 4.J2 Env and tested against autologous plasma antibodies. As shown in Figure 2, we found that while 4.J2 (N668S) retained similar sensitivity to autologous plasma as 4.J2, 4.J2 (H681Y) became resistant, suggesting that Y681 was responsible for neutralization resistance of 4.J22 Env clone in this patient. Interestingly, when tested against heterologous plasma antibodies obtained from five chronically infected patients, 4.J2 (containing H681) showed increased sensitivity while 4.J2 (H681Y) was found to be resistant (Figure 2). Our data indicated that H681 enhanced neutralization possibly by altering Env conformations.


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)

Construction of chimeric envelopes.Chimeric Envs were constructed by swapping of gp120 and gp41 between sensitive (4.J2) and resistant (4.J22) patient Envs using NotI, BbvCI and HindIII restriction enzymes. The ID50 values of pseudotyped viruses carrying 4.J2, 4.J22 and 4.J27 Envs to autologous plasma reported earlier [46] were shown on top; highlighted column represents ID50 of Env-pseudotyped viruses to contemporaneous plasma at the base line.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3351407&req=5

pone-0037157-g001: Construction of chimeric envelopes.Chimeric Envs were constructed by swapping of gp120 and gp41 between sensitive (4.J2) and resistant (4.J22) patient Envs using NotI, BbvCI and HindIII restriction enzymes. The ID50 values of pseudotyped viruses carrying 4.J2, 4.J22 and 4.J27 Envs to autologous plasma reported earlier [46] were shown on top; highlighted column represents ID50 of Env-pseudotyped viruses to contemporaneous plasma at the base line.
Mentions: We previously described [46] two clade C Env clones 4.J2 and 4.J22 obtained from a recently infected Indian patient at the baseline (at the same time point) which differed in their sensitivities to autologous plasma antibodies (ID50 of 4.J2 = 1∶540 against ID50 of 4.J22<100) (Figure 1A). The Env clones obtained were within one year of infection as determined by detuned ELISA as described earlier [46]. Sequence comparison between these two Envs revealed differences of altogether six residues in gp160, two in V1V2 domain (at positions 148 and 174 respectively) of gp120 and four in gp41 (Figure 1B). Out of the four residues that differed between these two Envs in gp41 domain, two were in the MPER region at positions 668 and 681, while the two others were at positions 551 and 839. We first investigated domains in Env that modulated sensitivity to contemporaneous autologous plasma by constructing Env chimeras between 4.J2 and 4.J22. Pseudotyped viruses carrying chimeric Env constructs were tested for their neutralization sensitivity to autologous contemporaneous plasma antibodies. As shown in Figure 2, as opposed to the wild type, 4.J2 containing gp41 grafted from 4.J22 conferred resistance while 4.J22 containing gp41 from 4.J2 became sensitive to autologous antibodies, indicating that gp41 in these Envs conferred altered sensitivities to autologous plasma antibodies in this patient. Since residues at positions 668 and 681 in these Envs were within MPER, a region of effective target of neutralizing antibodies, and in very close proximities to motifs that are targets of 2F5 and 4E10, we substituted N668S and H681Y (668S and 681Y were present in resistant Env 4.J22) in the sensitive 4.J2 Env and tested against autologous plasma antibodies. As shown in Figure 2, we found that while 4.J2 (N668S) retained similar sensitivity to autologous plasma as 4.J2, 4.J2 (H681Y) became resistant, suggesting that Y681 was responsible for neutralization resistance of 4.J22 Env clone in this patient. Interestingly, when tested against heterologous plasma antibodies obtained from five chronically infected patients, 4.J2 (containing H681) showed increased sensitivity while 4.J2 (H681Y) was found to be resistant (Figure 2). Our data indicated that H681 enhanced neutralization possibly by altering Env conformations.

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