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A new quaternary structure epitope on dengue virus serotype 2 is the target of durable type-specific neutralizing antibodies.

Gallichotte EN, Widman DG, Yount BL, Wahala WM, Durbin A, Whitehead S, Sariol CA, Crowe JE, de Silva AM, Baric RS - MBio (2015)

Bottom Line: While primary DENV2 infections stimulate serotype-specific protective responses, a leading vaccine failed to induce a similar protective response.Despite the complexity of the epitope, it was possible to transplant the epitope between DENV serotypes.Our findings have immediate implications for evaluating dengue vaccines in the pipeline as well as designing next-generation vaccines.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.

No MeSH data available.


Related in: MedlinePlus

Design and characterization of rDENV4/2. (A) Amino acid alignment of DENV2 and DENV4 linear envelope domain III (EDIII) sequence, showing residues 296 to 395 of the entire E sequence (99 amino acids [aa] total). Residues differing between DENV2 and DENV4 are highlighted in yellow. Recombinant DENV4 virus containing EDIII from DENV2, designated rDENV4/2, replaces differing residues from DENV4 with those from DENV2, highlighted in green (40 aa total). A residue generated from the escape mutant is highlighted in magenta. (B) Crystal structure model of the DENV2 E protein dimer, with swapped residues colored in green and the DENV2 type-specific MAb 2D22 escape mutant residue highlighted in magenta. (C) Vero-81 or C6/36 cells were inoculated, viral supernatants were collected every 24 h, and the viral titer was subsequently determined on the respective cell type, or 1% of U937+DC-SIGN cells were infected, and the total percentage of infection was measured every 12 h (mean ± SD). (D) Immunoblotting of C3/36-grown viruses with anti-E and anti-PrM antibodies. The molecular mass of E is 55 kDa, and the molecular mass of prM is 21 kDa.
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fig1: Design and characterization of rDENV4/2. (A) Amino acid alignment of DENV2 and DENV4 linear envelope domain III (EDIII) sequence, showing residues 296 to 395 of the entire E sequence (99 amino acids [aa] total). Residues differing between DENV2 and DENV4 are highlighted in yellow. Recombinant DENV4 virus containing EDIII from DENV2, designated rDENV4/2, replaces differing residues from DENV4 with those from DENV2, highlighted in green (40 aa total). A residue generated from the escape mutant is highlighted in magenta. (B) Crystal structure model of the DENV2 E protein dimer, with swapped residues colored in green and the DENV2 type-specific MAb 2D22 escape mutant residue highlighted in magenta. (C) Vero-81 or C6/36 cells were inoculated, viral supernatants were collected every 24 h, and the viral titer was subsequently determined on the respective cell type, or 1% of U937+DC-SIGN cells were infected, and the total percentage of infection was measured every 12 h (mean ± SD). (D) Immunoblotting of C3/36-grown viruses with anti-E and anti-PrM antibodies. The molecular mass of E is 55 kDa, and the molecular mass of prM is 21 kDa.

Mentions: We recently described hMAb 2D22, which is a DENV2-specific strongly neutralizing antibody isolated from a person exposed to a primary DENV2 infection (10). Our studies also demonstrated that 2D22 recognizes a complex quaternary epitope displayed on the intact virus but not recombinant E protein. A point mutation at amino acid position 323 in EDIII (residue highlighted in magenta in Fig. 1A and B) led to complete escape from 2D22 neutralization, indicating that the epitope includes EDIII residues (10). Recently Fibriansah et al. solved the structure of 2D22 bound to DENV2 and demonstrated that the antibody bound to a quaternary epitope that was formed by EDIII and EDII on two different monomers within a single dimer (15). While MAbs are powerful tools for epitope mapping, it is the polyclonal serum antibody response derived from long-lived plasma cells that is protective in people. Here we demonstrate that 2D22 defines a new class of quaternary epitopes that are the main targets of serum neutralizing antibodies in people exposed to DENV2 infections or a leading live attenuated DENV2 vaccine candidate.


A new quaternary structure epitope on dengue virus serotype 2 is the target of durable type-specific neutralizing antibodies.

Gallichotte EN, Widman DG, Yount BL, Wahala WM, Durbin A, Whitehead S, Sariol CA, Crowe JE, de Silva AM, Baric RS - MBio (2015)

Design and characterization of rDENV4/2. (A) Amino acid alignment of DENV2 and DENV4 linear envelope domain III (EDIII) sequence, showing residues 296 to 395 of the entire E sequence (99 amino acids [aa] total). Residues differing between DENV2 and DENV4 are highlighted in yellow. Recombinant DENV4 virus containing EDIII from DENV2, designated rDENV4/2, replaces differing residues from DENV4 with those from DENV2, highlighted in green (40 aa total). A residue generated from the escape mutant is highlighted in magenta. (B) Crystal structure model of the DENV2 E protein dimer, with swapped residues colored in green and the DENV2 type-specific MAb 2D22 escape mutant residue highlighted in magenta. (C) Vero-81 or C6/36 cells were inoculated, viral supernatants were collected every 24 h, and the viral titer was subsequently determined on the respective cell type, or 1% of U937+DC-SIGN cells were infected, and the total percentage of infection was measured every 12 h (mean ± SD). (D) Immunoblotting of C3/36-grown viruses with anti-E and anti-PrM antibodies. The molecular mass of E is 55 kDa, and the molecular mass of prM is 21 kDa.
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fig1: Design and characterization of rDENV4/2. (A) Amino acid alignment of DENV2 and DENV4 linear envelope domain III (EDIII) sequence, showing residues 296 to 395 of the entire E sequence (99 amino acids [aa] total). Residues differing between DENV2 and DENV4 are highlighted in yellow. Recombinant DENV4 virus containing EDIII from DENV2, designated rDENV4/2, replaces differing residues from DENV4 with those from DENV2, highlighted in green (40 aa total). A residue generated from the escape mutant is highlighted in magenta. (B) Crystal structure model of the DENV2 E protein dimer, with swapped residues colored in green and the DENV2 type-specific MAb 2D22 escape mutant residue highlighted in magenta. (C) Vero-81 or C6/36 cells were inoculated, viral supernatants were collected every 24 h, and the viral titer was subsequently determined on the respective cell type, or 1% of U937+DC-SIGN cells were infected, and the total percentage of infection was measured every 12 h (mean ± SD). (D) Immunoblotting of C3/36-grown viruses with anti-E and anti-PrM antibodies. The molecular mass of E is 55 kDa, and the molecular mass of prM is 21 kDa.
Mentions: We recently described hMAb 2D22, which is a DENV2-specific strongly neutralizing antibody isolated from a person exposed to a primary DENV2 infection (10). Our studies also demonstrated that 2D22 recognizes a complex quaternary epitope displayed on the intact virus but not recombinant E protein. A point mutation at amino acid position 323 in EDIII (residue highlighted in magenta in Fig. 1A and B) led to complete escape from 2D22 neutralization, indicating that the epitope includes EDIII residues (10). Recently Fibriansah et al. solved the structure of 2D22 bound to DENV2 and demonstrated that the antibody bound to a quaternary epitope that was formed by EDIII and EDII on two different monomers within a single dimer (15). While MAbs are powerful tools for epitope mapping, it is the polyclonal serum antibody response derived from long-lived plasma cells that is protective in people. Here we demonstrate that 2D22 defines a new class of quaternary epitopes that are the main targets of serum neutralizing antibodies in people exposed to DENV2 infections or a leading live attenuated DENV2 vaccine candidate.

Bottom Line: While primary DENV2 infections stimulate serotype-specific protective responses, a leading vaccine failed to induce a similar protective response.Despite the complexity of the epitope, it was possible to transplant the epitope between DENV serotypes.Our findings have immediate implications for evaluating dengue vaccines in the pipeline as well as designing next-generation vaccines.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.

No MeSH data available.


Related in: MedlinePlus