Proliferative response of murine B-cell leukemia (BCL1) to poly(L-lysine)

Peripheral blood lymphocytes (PBL) isolated from BALB/c mice bearing a B-cell leukemia (BCL1) showed a marked proliferative response upon two days culturing with poly(L-lysine) (PLL) of various molecular weights. An inverse relationship was noted between the molecular weight of the PLL and the dose required for optimal proliferative response. PLL showed no proliferative activity when cultured with normal PBL or with lymphocytes isolated from the spleen or other lymphoid organs of BCL1-bearing mice. Double exposure to PLL and lipopolysaccharide (LPS) had a marked synergistic effect on BCL1 PBL stimulation but not on PBL isolated from normal mice. The data suggest that PLL, in contrast to LPS, may cause a selective proliferation of a subpopulation(s) of B-tumor cells at a particular stage(s) of differentiation.