Purification of an in vitro inhibitor of normal myelopoiesis using a monoclonal antibody directed to a common antigen of myelogenous leukemia (CAMAL).
A monoclonal antibody, CAMAL-1, has been previously shown to react specifically and at high frequencies with cells of patients with acute myelogenous leukemia (AML) and chronic granulocytic leukemia (CGL). High expression of this antigen in remission patients' bone marrow cells was shown to correlate with both relapse and lower survival times. Preliminary studies showed that material extracted from leukemic cells and eluted from CAMAL-1 immunoadsorbent columns profoundly inhibited the formation of normal colony-forming units (CFU) but had no effect on formation of such colonies from cells of patients with CGL. We have used CAMAL-1 affinity chromatography in combination with FPLC gel filtration to purify the inhibitory material from leukemic cell extracts. We have successfully isolated a 30-kd component (P30) that functions as an inhibitor of normal myelopoiesis in vitro; when P30 was added to normal progenitor cell assays it significantly inhibited the growth of normal CFU but had no inhibitory effect on the growth of CGL progenitor cells at equivalent concentrations. The inhibitory effect is preferentially directed to granulocytic progenitors. Antibodies raised to P30 reacted in Western blot analyses with affinity purified material from patients' cells as well as with a 30-kd component in the cell lysates and supernatants of the leukemic cell lines HL60 and K562; this finding suggested that the P30 inhibitory component might be produced by leukemic cells.
Shellard
J E
JE
Department of Microbiology, University of British Columbia, Vancouver, Canada.
Leitch
H A
HA
Logan
P M
PM
McMaster
W R
WR
Levy
J G
JG
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D015214:Antigens, Differentiation, Myelomonocytic / Q000276:immunology* / Q000302:isolation & purification / Q000502:physiology; D000951:Antigens, Neoplasm / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology; D015153:Blotting, Western; D001853:Bone Marrow / Q000187:drug effects / Q000502:physiology; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002846:Chromatography, Affinity; D006412:Hematopoietic Stem Cells / Q000737:chemistry / Q000187:drug effects* / Q000276:immunology; D006801:Humans; D007951:Leukemia, Myeloid / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors
D000911:Antibodies, Monoclonal; D015214:Antigens, Differentiation, Myelomonocytic; D000951:Antigens, Neoplasm; D009363:Neoplasm Proteins; C061798:common myelogenous leukemia-associated antigen