Indirect ELISA analysis of Dengue Virus or VLP specific IgG antibody. BALB/c mice were intraperitoneally immunized with 25 μg monovalent DENV1-4 VLP, DENV1-4 virions, or tetravalent combination (25 μg of each serotype) a total of three times at two-week intervals. Sera were collected on days 0, 13, 27, and 34 and indirect ELISA was used to test for antigen specific IgG. Sera from monovalent VLP groups and the tetravalent VLP group reacted with DENV1-4 VLP antigens and sera from inactivated DENV groups reacted with dengue virus 1–4 antigens. Data are expressed as mean absorbance at OD450 nm with a standard error of the mean (SEM) bar. The baseline (dashed line) indicates negative values with normal mouse serum. A. Binding of sera from mice immunized with DENV1-VLP and inactivated DENV1 virions to respective antigens; B. Binding of sera from mice immunized with DENV2-VLP and inactivated DENV2 virions to respective antigens; C. Binding of sera from mice immunized with DENV3-VLP and inactivated DENV3 virions to respective antigens; D. Binding of sera from mice immunized with DENV4-VLP and inactivated DENV4 virions to respective antigens; 0045. Binding of sera from mice immunized with tetravalent VLP to respective antigens.