To test the concept that co-modulation of T cells and B cells once experimental HP is established could alleviate the inflammatory response to an antigenic re-encounter, mice were injected i.p. with antibodies directed against CD8, CD4, and/or CD19 after they were exposed to MSS three times a week for three or four weeks (see methods for clones and details). This evidence concerns the gene CD8A and hypersensitivity pneumonitis.