Premium
Interleukin‐4 inhibits apoptotic cell death and loss of the bcl‐2 protein in B‐chronic lymphocytic leukaemia cells in vitro
Author(s) -
Panayiotidis Panayiotis,
Ganeshaguru Kanagasabai,
Jabbar Shireen A. B.,
Hoffbrand A. Victor
Publication year - 1993
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1993.tb03330.x
Subject(s) - apoptosis , dna fragmentation , microbiology and biotechnology , programmed cell death , biology , in vitro , fragmentation (computing) , cell culture , monoclonal antibody , monoclonal , chronic lymphocytic leukemia , immunology , antibody , leukemia , biochemistry , ecology , genetics
Summary. When monoclonal B cells from B‐chronic lymphocytic leukaemia (B‐CLL) patients are cultured in vitro , they die by apoptosis. Apoptotic cell death occurred in the B cells from 20/24 B‐CLL patients after 26–30 h in in vitro culture, with 14.3–59.0% (mean 33.6%) of their DNA being fragmented in ∼180 base pair multimers. After 8–10 d culture, 90–100% of the B‐CLL cells were dead. Cell death and DNA fragmentation were inhibited in the presence of 0.5–5 ng/ml human recombinant interleukin‐4 (IL‐4) and viable monoclonal B cells could be maintained in culture up to 3 weeks. At 5 ng/ml. IL‐4 reduced DNA fragmentation after a 26–30 h culture to 2.2–33.3% (mean 14.9%). IL‐4 inhibited apoptosis without stimulating cell proliferation. In four patients the cells were resistant to apoptosis in vitro and they could be maintained for up to 4 weeks in culture medium alone. DNA fragmentation in all patients was increased in the presence of the RNA synthesis inhibitor actinomycin‐D. Western blot analysis of cell lysates showed expression of the bcl‐2 protein in all 11 B‐CLL patients studied. However, during culture, bcl‐2 protein levels were preserved only in patients resistant to apoptosis and were reduced in those susceptible to apoptosis. Reduction of bcl‐2 protein levels was inhibited in cells cultured in the presence of IL‐4. These data offer an explanation for the difference between the long life in vivo and rapid death in vitro of B‐CLL cells and indicate that IL‐4 may participate in the extended survival of these non‐dividing cells in vivo .