Fig. 3.

Sabin virus neutralizing antibody titers against poliovirus type 1, 2 and 3, three weeks after the third immunization in cynomolgus monkeys immunized with different polio vaccines. Cynomolgus monkeys (6 per group) were intramuscularly immunized with PER.C6®-based Sabin IPV (sIPV), or a reference Salk IPV (ref cIPV, Imovax, Sanofi) or a reference sIPV (ref sIPV, Kunming). For both commercial vaccines, one full human dose was used, and for the PER.C6®-based sIPV four different D-antigen unit dose formulations were tested, annotated as H, M, M-L and L. The different dose formulations represent: H = high dose formulation (20-30-100 DU), M = mid dose (10-15-50 DU), M-L = mid low dose (5-7.5-25 DU), L- low dose (2.5-3.75-12.5 DU). Three weeks after the third immunization sera were collected and analyzed with Sabin virus neutralizing antibody assays. The titration endpoint per animal is presented as a reciprocal of the titer. Dots represent individual animals. Horizontal lines show geometric means. The dotted line is the cut-off for seroprotection in humans (serum dilution of 1:8).