This site needs JavaScript to work properly. Please enable it to take advantage of the complete set of features!
Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

NIH NLM Logo
Log in
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Sep 19;7(9):e2451.
doi: 10.1371/journal.pntd.0002451. eCollection 2013.

Analysis of cross-reactive antibodies recognizing the fusion loop of envelope protein and correlation with neutralizing antibody titers in Nicaraguan dengue cases

Affiliations

Analysis of cross-reactive antibodies recognizing the fusion loop of envelope protein and correlation with neutralizing antibody titers in Nicaraguan dengue cases

Chih-Yun Lai et al. PLoS Negl Trop Dis. .

Abstract

Dengue virus (DENV) is the leading cause of arboviral diseases in humans worldwide. The envelope (E) protein of DENV is the major target of neutralizing antibodies (Abs). Previous studies have shown that a significant proportion of anti-E Abs in human serum after DENV infection recognize the highly conserved fusion loop (FL) of E protein. The role of anti-FL Abs in protection against subsequent DENV infection versus pathogenesis remains unclear. A human anti-E monoclonal Ab was used as a standard in a virion-capture ELISA to measure the concentration of anti-E Abs, [anti-E Abs], in dengue-immune sera from Nicaraguan patients collected 3, 6, 12 and 18 months post-infection. The proportion of anti-FL Abs was determined by capture ELISA using virus-like particles containing mutations in FL, and the concentration of anti-FL Abs, [anti-FL Abs], was calculated. Neutralization titers (NT50) were determined using a previously described flow cytometry-based assay. Analysis of sequential samples from 10 dengue patients revealed [anti-E Abs] and [anti-FL Abs] were higher in secondary than in primary DENV infections. While [anti-FL Abs] did not correlate with NT50 against the current infecting serotype, it correlated with NT50 against the serotypes to which patients had likely not yet been exposed ("non-exposed" serotypes) in 14 secondary DENV3 and 15 secondary DENV2 cases. These findings demonstrate the kinetics of anti-FL Abs and provide evidence that anti-FL Abs play a protective role against "non-exposed" serotypes after secondary DENV infection.

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Measurement of [anti-E Abs] in human sera by capture ELISA.
(A) Virion-capture ELISA was performed using serial dilutions of a human mAb 82.11 with known concentrations to generate a standard curve. (B) Sequential human serum samples from a dengue patient were tested simultaneously with the standard and the OD values were interpolated to determine [anti-E Abs]. Data are means with standard deviation of duplicates from one representative experiment of two. (C) The binding specificity of mAb 82.11 was determined by Western blot analysis using cell lysates collected from Vero cells infected with mock, DENV1 (Hawaii strain), DENV2 (NGC strain), DENV3 (H87 strain), DENV4 (H241 strain) or WNV (NY99 strain) . The NT50 and dissociation constant (Kd) of mAb 82.11 are summarized on the right. The viron-capture ELISA of DENV1, DENV2 and DENV3 was performed using serial dilutions of mAb 82.11; the Kd was determined using the program GraphPad Prism 5.0. Data are means of duplicates from one representative experiment of two. ND, not done.
Figure 2
Figure 2. Determination of % anti-FL Abs in serum of a dengue patient by VLP-capture ELISA.
(A) Serial dilutions of the serum were subjected to a capture ELISA using DENV1 WT and mutant VLPs containing mutations in the FL epitope (W101A+F108A). The bar graph displaying results from an anti-E ELISA shows that comparable amounts of WT and mutant VLPs were added based on recognition of E by pooled human dengue-immune sera. % anti-FL Abs = [1 – endpoint titer to mutant VLPs/endpoint titer to WT VLPs×ばつ100%. (B) The same serum was subjected to a capture ELISA using DENV2 WT and mutant VLPs (W101A+F108A). Data are presented as in (A). Data are means with standard deviation of duplicates from one representative experiment of two. For endpoint titers, only means are shown.
Figure 3
Figure 3. Kinetics of [anti-E Abs] and [anti-FL Abs] in sera of dengue patients.
(A) [anti-E Abs] and (B) [anti-FL Abs] in samples collected 3, 6, 12 and 18 months post-infection. Green closed symbols, patients with primary DENV infection; red open symbols, patients with secondary DENV infection.
Figure 4
Figure 4. Relationship between [anti-FL Abs] and NT50 against current infecting and "non-exposed" serotypes in secondary DENV infection.
The current infecting serotype, previous infecting serotype(s) and "non-exposed serotypes" were determined as described in Methods. [anti-FL Abs] and NT50 against the current infecting serotype (A, E) and "non-exposed" serotypes (B to D, F to H) in patients with secondary DENV3 (A to D) and secondary DENV2 (E to H) infections.

References

    1. Guzman MG, Halstead SB, Artsob H, Buchy P, Farrar J, et al. (2010) Dengue: a continuing global threat. Nat Rev Microbiol 12: S7–S16. - PMC - PubMed
    1. World Health Organization. (2009) Dengue hemorrhagic fever: Diagnosis, treatment, prevention and control, 3rd ed. Geneva, Switzerland.
    1. Whitehead SS, Blaney JE, Durbin AP, Murphy BR (2007) Prospects for a dengue virus vaccine. Nat Rev Microbiol 5: 518–528. - PubMed
    1. Lindenbach BD, Thiel HJ, Rice CM. (2007) Flaviviridae: the viruses and their replication, In Knipe DM, Howley PM eds: Fields virology, 5th ed. Philadelphia, PA: Lippincott William & Wilkins, pp. 1101–1152.
    1. Heinz FX, Stiasny K (2006) Flavivirus membrane fusion. J Gen Virol 87: 2755–2766. - PubMed

Publication types

Full text links
Public Library of Science full text link Public Library of Science Free PMC article
Cite

AltStyle によって変換されたページ (->オリジナル) /