The document describes immunohistochemistry protocols for testing a desmin monoclonal antibody (clone 1B12) on paraffin-embedded tissue samples from human lung, rat heart, spleen and mouse lung, spleen. The protocol involves tissue processing, antigen retrieval using citric acid, blocking endogenous peroxidase, primary antibody incubation with the desmin antibody, secondary antibody incubation, DAB staining, hematoxylin counterstaining, dehydration, clearing and visualization under a microscope. The protocols are provided to validate the desmin antibody for immunohistochemistry applications on the specified species and tissue types.