Description: The HIS19 monoclonal antibody reacts with a polymorphic epitope of the rat MHC class II molecule, RT1B. This antibody reacts with all rat haplotypes except the RT1n (including BN and MAXX strains). The rat MHC class II (I-A equivalent), RT1B, is expressed by antigen presenting cells including B cells, dendritic cells and macrophages.