Fig. 6.

Fab DN4, that does not recognize the thyroid peroxidase (TPO) immunodominant region, has a low affinity for TPO (unlike other TPO-selected Fab), yet it binds specifically to TPO (like other native (N)-TPO and denatured (DN)-TPO selected Fab). (a) ¹²⁵I-TPO bound (% maximum) in the presence of increasing concentrations of unlabelled TPO by Fab DN4 and three other DN-TPO-selected clones representative of clones with the other D regions. Binding in the absence of unlabelled TPO: DN4, 21.8%; DN8, 27.2%; DN14, 18.3%; DN16, 19.5%. (b) Optical densities (492 nm) for Fab DN4, DN14, N2 and N6 incubated with ELISA wells coated with TPO, lactoperoxidase (LPO), myeloperoxidase (MPO), thyroglobulin (Tg), transferrin (Tsfn) and keyhole limpet haemocyanin (KLH). Fab binding was detected with mouse MoAb to human κ-chains. All samples were analysed simultaneously and data are the means of closely agreeing duplicate wells.