Fig 4.

Stability of alga-produced CtxB-Pfs25 in lyophilized algae. (A) Soluble protein extracts from JAG101 (both pre- and postlyophilization) and ΔpsbA C. reinhardtii strains were serially diluted and applied to GM1 ganglioside-coated ELISA plates in triplicate. Binding was detected with anti-CT antibodies. (B) Lyophilized JAG101 C. reinhardtii was stored at 4°C, 22°C, and 37°C; lyophilized ΔpsbA C. reinhardtii was stored at 4°C. Soluble protein extracts were prepared on the indicated days, serially diluted, and applied to GM1 ganglioside-coated ELISA plates in triplicate. Binding was detected with anti-CT Abs. Error bars shown are 1 standard deviation. Binding endpoints were defined as the last dilution with an absorbance greater than that of the ΔpsbA strain at 10 μg/ml plus 3 standard deviations.