Figure 4.

IgA measurements using sandwich ILISA. (a) Titration of 2-MEA (mM) for fragmentation of a rabbit anti-human IgA antibody. The resulting antibody fragments were examined with PAGE. The red star marks the IgG fragment resulted from the reduction of the disulfide bond at the hinge region. (b) A representative standard curve generated using purified human IgA. The red-dotted rectangle marks the linear portion of the curve shown in (c). (d) Human IgA in both normal and disease-state serum samples was quantified with sandwich ILISAs. Data represent means ± SD of three measurements.