The document reports the validation of a polyclonal rabbit anti-Smad2 antibody for immunofluorescence applications. It describes immunofluorescence analysis of rat lung, rat spleen, and mouse lung tissues using the anti-Smad2 antibody and a Cy3-labeled secondary antibody, followed by DAPI counterstaining. The protocol details tissue processing, antigen retrieval, blocking, primary and secondary antibody incubations, mounting, and microscopy parameters.