Fig. 4.
Accelerated and real-time stability study over 12 weeks for NRRV P[8] parent antigen Pp P[8] and variant Pp P[8]-N85Q,N151Q,C171S in solution. Samples were prepared ± thimerosal at 4 °C (solid lines), 25 °C (dashed lines) and 37 °C (dotted lines) and stability was monitored by DSC and ELISA. (a) Representative DSC thermograms of NRRV proteins in solution at time 0 at 4 °C with indicated Tm values. Storage stability profiles of P[8] samples at 4 °C, 25 °C, and 37 °C as measured by DSC (apparent enthalpy values, ΔH′) either (b) without thimerosal, or (c) in the presence of 0.01% w/v thimerosal. (d) Representative ELISA dose response curves at time 0 after storage at 4 °C. Storage stability profiles of P[8] samples at 4 °C, 25 °C, and 37 °C as measured by ELISA either (e) without thimerosal, or (f) in the presence of 0.01% w/v thimerosal. Stability samples contained 0.12 mg/mL protein in 10 mM sodium phosphate, 150 mM NaCl, pH 7.0. Error bars represent mean and range of values with n = 2 (2 sample vials × 1 measurement/vial) for DSC, and mean ± 1 SD for n = 4 (2 sample vials x 2 measurements/vial) for ELISA.