Previous studies have shown that the strongly neutralizing mAb, subcomplex-specific 1A1D-2 and cross-reactive 9F12 recognized residues at K305, K307 and K310 in A-strand [15, 17] . Our mAb DB32-6 is a serotype-specific neutralizing mAb that recognized residue K310 but not residues K305 or K307. Although K310 is considered as a subcomplex-specific epitope, DB32-6 is a serotypespecific mAb. There may be other regions that affect the binding of DB32-6 to DENV-2. We found that by mutating residue I312, DB32-6's binding activity was reduced by 50% (data not shown). Residue I312 may be a minor epitope of DB32-6. Moreover, 1A1D-2 is a temperature dependent mAb due to its needs for dynamic motion on the virion surface to neutralize virus [16] . Different from 1A1D-2, DB32-6 is temperature independent. When DB32-6 was incubated with DENV at 4uC, it still exhibited significant neutralizing activity (Figures 2 and 6 ). As expected, when incubating the DENV and DB32-6 at 37uC, DB32-6 showed better efficacy than it did at 4uC (data not shown). The residue K310 on the surface of DENV-2 may be accessible to DB32-6 binding. Additionally, DB32-6 had high binding affinity (0.12-0.18 nM) to DENV-2. Based on the above finding, the residue K310 induce serotype-specific mAbs and is crucial in the neutralization of virus infectivity.