Demonstration of high-affinity interleukin-2 receptors on B-chronic lymphocytic leukemia cells: functional and structural characterization.
Functional and structural characteristics of interleukin 2 (IL-2) receptors on B-cell chronic lymphocytic leukemia (B-CLL) cells were analyzed by a proliferation assay, IL-2 binding assay and cross-linking study. In the 3H-thymidine incorporation assay, purified B-CLL cells from four out of sixteen cases, in which the percentage of Tac antigen (Tac Ag) positive cells in peripheral blood lymphocytes ranged from 0 to 48.8%, responded to IL-2 (100 U/ml) after both 3- and 6-day incubation. No relationship was found between the responsiveness to IL-2 and the percentage of Tac Ag positive cells. In the radiolabeled IL-2 binding assay, however, B-CLL cells from all seven cases examined, including three cases with mitogenic response to IL-2 and four cases without mitogenic response, were shown to have both high- and low-affinity receptors. The number of high- and low-affinity receptors per cell ranged from 29-186 and from 420 to 1,800, respectively. Furthermore, with the affinity cross-linking method p55 (Tac Ag) and p70/75 were found even in cases without mitogenic response in their B-CLL cells. In conclusion, the B-CLL cells so far examined possessed high-affinity IL-2 receptors consisting of p55 and p70/75; nevertheless, this was not sufficient to respond to the mitogenic signal of IL-2.
Yagura
H
H
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Tamaki
T
T
Furitsu
T
T
Tomiyama
Y
Y
Nishiura
T
T
Tominaga
N
N
Katagiri
S
S
Yonezawa
T
T
Tarui
S
S
D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D004247:DNA / Q000096:biosynthesis; D005455:Fluorescent Antibody Technique; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D046911:Macromolecular Substances; D008970:Molecular Weight; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology
D007136:Immunoglobulins; D007376:Interleukin-2; D046911:Macromolecular Substances; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins; D004247:DNA