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. 2015 Jan 8;9(1):e3445. doi: 10.1371/journal.pntd.0003445

Figure 3. Association of E2EP3 cross-reactive antibody responses with CHIKV neutralizing activity.

Figure 3

A, Anti-E2EP3 antibody response in serum samples (High E2EP3 IgG responders, n = 10; Low E2EP3 IgG responders, n = 15), at a dilution of 1∶4,000 were determined by ELISA using biotinylated E2EP3 peptides. Data are presented as mean ± SEM. Data are representative of two independent experiments with similar results. Statistical significance was measured using Mann-Whitney U test (***P<0.0001). B, In-vitro neutralizing activity against CHIKV in High and Low E2EP3 IgG responders. Histogram shows the percentage of patient samples with or without CHIKV neutralizing activity. Statistical significant was measured using 2-sided Fisher exact test between the patient samples with and without CHIKV neutralizing activity in the 2 responder groups. *P = 0.028. C - D, E2EP3 sequence from CHIKV was aligned to corresponding sequences from 9 non-CHIKV alphaviruses (ONNV, RRV, SFV, MAYV, BFV, SINV, VEEV, EEEV and WEEV). Conserved amino acid (A.A.) are indicated by a *. Percentage similarity between CHIKV E2EP3 sequence and corresponding sequence from each non-CHIKV alphavirus were calculated with SIAS (http://imed.med.ucm.es/Tools/sias.html). Percentage similarity relative to CHIKV E2EP3 is indicated by a bar-chart. Viruses classified as Old World alphaviruses are marked by the grey shading box, while viruses classified as New World alphaviruses are marked by the white box. NCBI Genbank accession numbers of ten selected alphaviruses (CHIKV - DQ443544, ONNV - O90369, RRV - AEC49728, SFV - ABA29033, MAYV - AAL79764, BFV - NP819000, SINV - ACU25462, VEEV - AAB02519, EEEV - NP740646, WEEV - NP818940).