Figure 4.
Comparisons of the immunoreactivities of AK23 IgM, AK23 IgG, and F(ab′)2 fragments of AK23 IgM. A: Indirect immunofluorescence (IIF) staining of hard palate tissue from wild-type mice. Sera from AK23 IgM transgenic mice and AK23 IgM mAb yielded no signal, whereas AK23 IgG and AK23 IgM F(ab′)2 yielded linear cell surface staining. Insets, digitally enlarged. Dotted lines indicate the basement membrane. B: Live staining of mouse PAM212 keratinocytes. Both AK23 IgM and AK23 IgG stained keratinocyte cell surfaces, but the staining patterns were quite different. AK23 IgM appeared as coarse dots on cell border-free areas. C: AK23 IgM and AK23 IgG (green) were costained with desmoplakin (red). Although AK23 IgG largely colocalized with desmoplakin, AK23 IgM did not. D: Quantification of colocalization indicated significantly lower colocalization of DP with AK23 IgM than with AK23 IgG. *P < 0.005. Scale bars = 50 μm.