Immunogenicity of plant extracts. Analysis of serum from New Zealand white rabbits #11 and #12 immunized with A. thaliana-derived HPV-11 L1 NLS- VLPs and rabbits #13 to #18 immunized with N. tabacum-derived HPV-11 L1 NLS- VLPs. Rabbits were immunized on days 1, 28 and 56 and serum from days 1, 15, 28, 42, 56 and 70 post injection was tested by ELISA in wells coated with 0.4 μg insect cell-derived HPV-11 L1 NLS- VLPs. Data from rabbit #12 is incomplete as it had to be euthanized due to growth of an abscess on the neck. Error bars represent the standard deviation calculated from triplicate analysis of samples.