Development of a model of chronic lymphocytic leukemia in inbred strain 2 guinea pigs

A new transplantable leukemia (KSL) of unknown etiology that arose in a female Sewall-Wright strain 2 guinea pig is described. KSL cells morphologically resembled medium to large lymphocytes, displayed surface Ia antigen and receptors for complement and for the Fc portion of immunoglobulin, and synthesized surface immunoglobulin (IgM). These characteristics suggest a leukemia of B-lymphocyte origin. KSL cells were shown to be sensitive in vivo to both cyclophosphamide and 1,3-bis(2-chloroethyl)-1-nitrosourea; however, neither drug effectively prevented eventual recurrence of the disease. KSL leukemia was also shown to be distinct from another guinea pig lymphatic leukemia (L2C) with respect to cell morphology, antigenicity, and in vivo growth rate. In this last respect, KSL appeared more closely related to the chronic lymphocytic leukemias. Thus KSL is the first chronic lymphocytic leukemia in the guinea pig to be characterized; it is also the only guinea pig model of lymphatic leukemia that is distinct from L2C leukemia currently available for study.