Immunofluorescence analysis of the line specificity of APP antibody. E (A, C, and E) or PE (B, D, and F) were incubated with NP (A and B), homologous anti-P. c. chabaudi AS APP (C and D), and heterologous anti-P. c. chabaudi CB APP (E and F), and antibody binding was detected in triplicate samples. The window was determined by using E or PE incubated with KGS alone instead of plasma.