Titers of antibodies in the day 37 antisera of 1a−d reactive to sTnNPhAc-HSA (white bars), sTnNMePhAc-HSA (dotted bars, 2a), sTnNMeOPhAc-HSA (hatched bars, 2b), sTnNAcPhAc-HSA (diagonally striped bars, 2c), and sTnNClPhAc-HSA (gray bars, 2d), respectively. The arrows (→) highlight the antibody titers of the antisera, where the sTnNPhAc derivative employed to immunize animals was used to coat ELISA plates as well. In all of these experiments, pooled antisera from five replicate animals immunized with the indicated conjugates were used to obtain total antibody titers by ELISA.