Level of neutralizing activity in serum samples obtained from patients with secondary acute dengue infection and from selected non acute dengue patients against each of the 4 DENV serotypes.

a<p>Infecting serotype indicates the DENV serotype detected in the serum sample as determined by RT-PCR.</p>b<p>Neutralizing titers (PRNT₅₀) to each of the 4 DENV serotypes for five DENV-1 patients and for two DENV-3 patients were less than 10 (PRNT₅₀<10) by using FcγR-negative BHK cells and FcγR-expressing BHK cells and the results were not included in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001536#pntd-0001536-t003" target="_blank">Table 3</a>. Neutralizing antibody titer to 4 DENV serotypes were determined by a conventional PRNT method using FcγR-negative BHK cells and FcγR-expressing BHK cells as indicated in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001536#s2" target="_blank">Materials and Methods</a>.</p>c<p>Neutralizing antibody titers were determined for samples from selected non acute dengue patients.