Detection of HPV-11 L1 protein in plant extracts using ELISA. (A) VLP characterisation by ELISA, utilising conformation-specific and linear MAbs, of HPV-11 L1 NLS- transgenic T3 generation A. thaliana protein extract from pooled lines and (B) N. tabacum protein extract from individual lines and generations. (for example: X1.2 represents line X1, T2 generation). Non-transgenic A. thaliana or N. tabacum protein extract was used as negative control; the positive control consisted of non-transgenic protein extract spiked with 0.4 μg/well insect cell-derived HPV-11 L1 NLS- VLPs. Error bars represent the standard deviation calculated from triplicate analysis of samples.