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High-throughput sequencing analysis of post-liver transplantation HCV E2 glycoprotein evolution in the presence and absence of neutralizing monoclonal antibody.

Babcock GJ, Iyer S, Smith HL, Wang Y, Rowley K, Ambrosino DM, Zamore PD, Pierce BG, Molrine DC, Weng Z - PLoS ONE (2014)

Bottom Line: It has been previously reported that N415 is not glycosylated in the wild-type E2 protein, but N417S can lead to glycosylation at position 415.Thus N415 is a key position for antibody recognition and the only routes we identified for viral escape, within the constraints of HCV fitness in vivo, involve mutating or glycosylating this position.Evaluation of mutations along the entire E1 and E2 proteins revealed additional positions that changed moderately before and after MBL-HCV1 treatment for subsets of the six subjects, yet underscored the relative importance of position 415 in MBL-HCV1 resistance.

View Article: PubMed Central - PubMed

Affiliation: MassBiologics, University of Massachusetts Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Chronic hepatitis C virus (HCV) infection is the most common cause of end-stage liver disease, often leading to liver transplantation, in which case circulating virions typically infect the transplanted liver within hours and viral concentrations can quickly exceed pre-transplant levels. MBL-HCV1 is a fully human monoclonal antibody recognizing a linear epitope of the HCV E2 envelope glycoprotein (amino acids 412-423). The ability of MBL-HCV1 to prevent HCV recurrence after liver transplantation was investigated in a phase 2 randomized clinical trial evaluating six MBL-HCV1-treated subjects and five placebo-treated subjects. MBL-HCV1 treatment significantly delayed time to viral rebound compared with placebo treatment. Here we report results from high-throughput sequencing on the serum of each of the eleven enrolled subjects prior to liver transplantation and after viral rebound. We further sequenced the sera of the MBL-HCV1-treated subjects at various interim time points to study the evolution of antibody-resistant viral variants. We detected mutations at one of two positions within the antibody epitope--mutations of N at position 415 to D, K or S, or mutation of N at position 417 to S. It has been previously reported that N415 is not glycosylated in the wild-type E2 protein, but N417S can lead to glycosylation at position 415. Thus N415 is a key position for antibody recognition and the only routes we identified for viral escape, within the constraints of HCV fitness in vivo, involve mutating or glycosylating this position. Evaluation of mutations along the entire E1 and E2 proteins revealed additional positions that changed moderately before and after MBL-HCV1 treatment for subsets of the six subjects, yet underscored the relative importance of position 415 in MBL-HCV1 resistance.

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Changes in viral loads and epitope sequence distributions upon MBL-HCV1 antibody administration.A–F: Epitope distributions for subjects A, B, C, D, E and F respectively. X axis represents time point in days, 0 denoting pre-transplant baseline sample. Note the depletion of wild-type sequence in all patients and the emergence of resistant epitope sequences (see proportions in left Y axis), in conjunction with viral rebound (right Y axis). Positions 415 and 417 are highlighted in blue in the legend. G: Summary of antibody-resistant mutations in epitope sequences, assuming maximum parsimony. Glycosylation motifs are highlighted in orange.
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pone-0100325-g001: Changes in viral loads and epitope sequence distributions upon MBL-HCV1 antibody administration.A–F: Epitope distributions for subjects A, B, C, D, E and F respectively. X axis represents time point in days, 0 denoting pre-transplant baseline sample. Note the depletion of wild-type sequence in all patients and the emergence of resistant epitope sequences (see proportions in left Y axis), in conjunction with viral rebound (right Y axis). Positions 415 and 417 are highlighted in blue in the legend. G: Summary of antibody-resistant mutations in epitope sequences, assuming maximum parsimony. Glycosylation motifs are highlighted in orange.

Mentions: Three of the MAb-treated subjects (Subjects A, B, and C) experienced viral rebound of at least 2 log10 IU/ml by day 14 post-transplantation (Figure 1A–C). Subject A displayed a mixture of N415D (78.5%) and N417S (20.5%) as the predominant viral strains at the time of rebound. The rebounding population found in subject B was dominated by the variant N415K (97.1%). Subject C had a greater diversity at positions 415 and 417 than Subjects A or B at day 14, with N415D (56.0%), N415K (2.6%), and N417S (12.7%) mixing with quasispecies possessing wild-type epitope sequence (25.8%).


High-throughput sequencing analysis of post-liver transplantation HCV E2 glycoprotein evolution in the presence and absence of neutralizing monoclonal antibody.

Babcock GJ, Iyer S, Smith HL, Wang Y, Rowley K, Ambrosino DM, Zamore PD, Pierce BG, Molrine DC, Weng Z - PLoS ONE (2014)

Changes in viral loads and epitope sequence distributions upon MBL-HCV1 antibody administration.A–F: Epitope distributions for subjects A, B, C, D, E and F respectively. X axis represents time point in days, 0 denoting pre-transplant baseline sample. Note the depletion of wild-type sequence in all patients and the emergence of resistant epitope sequences (see proportions in left Y axis), in conjunction with viral rebound (right Y axis). Positions 415 and 417 are highlighted in blue in the legend. G: Summary of antibody-resistant mutations in epitope sequences, assuming maximum parsimony. Glycosylation motifs are highlighted in orange.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4067308&req=5

pone-0100325-g001: Changes in viral loads and epitope sequence distributions upon MBL-HCV1 antibody administration.A–F: Epitope distributions for subjects A, B, C, D, E and F respectively. X axis represents time point in days, 0 denoting pre-transplant baseline sample. Note the depletion of wild-type sequence in all patients and the emergence of resistant epitope sequences (see proportions in left Y axis), in conjunction with viral rebound (right Y axis). Positions 415 and 417 are highlighted in blue in the legend. G: Summary of antibody-resistant mutations in epitope sequences, assuming maximum parsimony. Glycosylation motifs are highlighted in orange.
Mentions: Three of the MAb-treated subjects (Subjects A, B, and C) experienced viral rebound of at least 2 log10 IU/ml by day 14 post-transplantation (Figure 1A–C). Subject A displayed a mixture of N415D (78.5%) and N417S (20.5%) as the predominant viral strains at the time of rebound. The rebounding population found in subject B was dominated by the variant N415K (97.1%). Subject C had a greater diversity at positions 415 and 417 than Subjects A or B at day 14, with N415D (56.0%), N415K (2.6%), and N417S (12.7%) mixing with quasispecies possessing wild-type epitope sequence (25.8%).

Bottom Line: It has been previously reported that N415 is not glycosylated in the wild-type E2 protein, but N417S can lead to glycosylation at position 415.Thus N415 is a key position for antibody recognition and the only routes we identified for viral escape, within the constraints of HCV fitness in vivo, involve mutating or glycosylating this position.Evaluation of mutations along the entire E1 and E2 proteins revealed additional positions that changed moderately before and after MBL-HCV1 treatment for subsets of the six subjects, yet underscored the relative importance of position 415 in MBL-HCV1 resistance.

View Article: PubMed Central - PubMed

Affiliation: MassBiologics, University of Massachusetts Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Chronic hepatitis C virus (HCV) infection is the most common cause of end-stage liver disease, often leading to liver transplantation, in which case circulating virions typically infect the transplanted liver within hours and viral concentrations can quickly exceed pre-transplant levels. MBL-HCV1 is a fully human monoclonal antibody recognizing a linear epitope of the HCV E2 envelope glycoprotein (amino acids 412-423). The ability of MBL-HCV1 to prevent HCV recurrence after liver transplantation was investigated in a phase 2 randomized clinical trial evaluating six MBL-HCV1-treated subjects and five placebo-treated subjects. MBL-HCV1 treatment significantly delayed time to viral rebound compared with placebo treatment. Here we report results from high-throughput sequencing on the serum of each of the eleven enrolled subjects prior to liver transplantation and after viral rebound. We further sequenced the sera of the MBL-HCV1-treated subjects at various interim time points to study the evolution of antibody-resistant viral variants. We detected mutations at one of two positions within the antibody epitope--mutations of N at position 415 to D, K or S, or mutation of N at position 417 to S. It has been previously reported that N415 is not glycosylated in the wild-type E2 protein, but N417S can lead to glycosylation at position 415. Thus N415 is a key position for antibody recognition and the only routes we identified for viral escape, within the constraints of HCV fitness in vivo, involve mutating or glycosylating this position. Evaluation of mutations along the entire E1 and E2 proteins revealed additional positions that changed moderately before and after MBL-HCV1 treatment for subsets of the six subjects, yet underscored the relative importance of position 415 in MBL-HCV1 resistance.

Show MeSH
Related in: MedlinePlus