Difference between the Abilities of Human Fcγ Receptor-Expressing CV-1 Cells To Neutralize American and Asian Genotypes of Dengue Virus 2

Sera from patients involved in a Peruvian outbreak of dengue virus serotype 1 infection cross-neutralized the American genotype of dengue virus serotype 2 up to 100-fold more efficiently than they did the virulent Asian genotype of dengue virus serotype 2, as determined by a plaque reduction neutralization test (PRNT) with CV-1 fibroblasts modified to express human Fc gamma receptor CD32. The concordant preferential immune enhancement of the Asian genotype of dengue virus serotype 2 in human monocytes suggests that such a modification might strengthen the correlation between the PRNT titer and protection.