The National Institute of Allergy and Infectious Diseases is developing, with the American Type Culture Collection, a central facility for the acquisition, maintenance, and distribution of hybridoma cell lines. This effort finds its principal justification in the great activity in this field and in the large variety of hybridoma lines that are produced because of the intrinsic immense diversity of antibodies the immune system is capable of generating. Thus there clearly needs to exist a mechanism both to facilitate exchange of these cell lines and to assure the preservation of the ones of greatest interest. The burgeoning involvement of commercial interests in the production and marketing of monoclonal antibodies complicates, but in no way vitiates the institute's efforts.