Hematopoietic cellular interactions: role of the major histocompatibility complex (MHC)

Factors that stimulate the growth of hematopoietic progenitors in vitro have been identified and the genes that encode these factors have been isolated. Nevertheless, defining hematopoietic regulation requires understanding how these factors are induced and function in the context of organized tissue. Defining these molecular events is, however, complicated by heterogenous cell populations present in hematopoietic tissue, which makes it difficult to assess the consequences of any specific cell-cell interaction. Recent advances in the identification of surface molecules involved in mediating recognition phenomenon between interacting cells makes it possible to begin dissecting specific interactions that may be restricted by the gene products of the major histocompatibility complex (MHC).