Abstract: The invention provides methods for treating pathological conditions associated with an undesirable inflammatory component, including graft-versus-host disease. The invention is generally directed to reducing inflammation by administering cells that express and/or secrete prostaglandin E2 (PGE2). The invention is also directed to drug discovery methods to screen for agents that modulate the ability of the cells to express and/or secrete PGE2, such as PGE2 receptor agonists. The invention is also directed to cell banks that can be used to provide cells for administration to a subject, the banks comprising cells having desired levels of PGE2 expression and/or secretion. The invention is also generally directed to delivering cells directly to lymphohematopoietic tissue, such as spleen, lymph nodes, and bone marrow. The invention is, thus, also directed to a method for treating inflammation by administering cells directly into sites of lymphohematopoiesis, such as spleen, lymph nodes, and bone marrow.