Rheumatoid synovial fibroblasts were used as an immunogen to produce monoclonal antibodies selected for their reactivity with stromal cell antigens. Mice were immunised with low passage whole cell preparations and the subsequent hybridomas were screened by immunohistochemistry on rheumatoid synovium and tonsil sections. The aim was to identify those antibodies that recognised antigens that were restricted to stromal cells and were not expressed on CD45 positive leucocytes. A significant number of antibodies detected antigen that identified endothelial cells. These antibodies were further characterised to determine whether the vessels identified by these antibodies were vascular or lymphatic. From five fusions clones were identified with predominant reactivity with: 1) fibroblasts and endothelial cells; or 2) broad stromal elements (fibroblast, endothelium, epithelium, follicular dendritic cells). A fibroblast-specific antibody that did not also identify vessels was not generated. Examples of each reactivity pattern are discussed. Rheumatoid synovial fibroblasts were used as an immunogen to produce monoclonal antibodies selected for their reactivity with stromal cell antigens. Mice were immunized with low passage whole cell preparations and the subsequent hybridomas were screened by immunohistochemistry on rheumatoid synovium and tonsil sections. The aim was to identify those antibodies that recognized antigens that were restricted to stromal cells and were not expressed on CD45 positive leucocytes. These antibodies were further characterised to determine whether the vessels identified by these antibodies were vascular or lymphatic . From Five fusions clones were identified with predominant reactivity with: 1) fibroblasts and endothelial cells; or 2) broad stromal elements (fibroblast, endothelium, epithelium, follicular dendritic cells). A fibroblast-specific antibody that did not also identify vessels was not generated. Examp les of each reactivity pattern are discussed.