Lack of interleukin-2 (IL-2) dependent growth of TAC positive T-ALL/NHL cells is due to the expression of only low affinity receptors for IL-2.
Binding of interleukin-2 (IL-2) to high affinity receptors on activated normal T cells was shown to be the essential step in induction of proliferation of such cells. The finding of abundant IL-2 receptors on malignant T cells in adult T cell leukemia suggested a deregulation of the IL-2/IL-2 receptor system and was assumed to account for aberrant growth in malignant disorders of T cells. In this study we use malignant T cells from nine patients with the clinical diagnosis of T-ALL or T-NHL and did not detect IL-2 dependent growth under conditions in which normal T cells responded to IL-2. IL-2 receptors comparable in numbers to activated T cells were found on T-ALL/T-NHL cells stimulated with PHA and PMA. However, binding studies using radiolabeled IL-2 indicated that the receptors present on malignant T cells were not able to bind to IL-2 with high affinity. Therefore, if IL-2 is involved in the proliferation of malignant T cells, its mechanism of growth regulation may be different from the one for normal T cells. Alternatively, IL-2 may not play a role in the regulation of growth of malignant T cells in vitro.
Debatin
K M
KM
Oncology-Immunology Section, University Children's Hospital, Heidelberg, F.R.G.
Woodroofe
C
C
Lahm
H
H
Fischer
J
J
Falk
W
W
Brandeis
W E
WE
Krammer
P H
PH
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000502:physiology*; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000276:immunology / Q000473:pathology*; D008213:Lymphocyte Activation; D008228:Lymphoma, Non-Hodgkin / Q000276:immunology / Q000473:pathology*; D008297:Male; D010641:Phenotype; D015375:Receptors, Interleukin-2 / Q000032:analysis*
D007376:Interleukin-2; D015375:Receptors, Interleukin-2