Interleukin 3 activates human blood basophils via high-affinity binding sites.
Pure populations of human basophilic granulocytes were obtained from chronic myeloid leukemia (CML) blood by negative selection using a mixture of monoclonal antibodies and complement. 125I-radiolabeled recombinant human interleukin 3 (rhIL-3) bound to purified basophils in a specific manner. Quantitative binding studies and Scatchard plot analyses performed on samples from two donors revealed the presence of a single class of high-affinity IL-3 binding sites (500 and 2100 sites per cell; dissociation constant at equilibrium, 230 and 160 pmol/liter, respectively). Purified CML basophils maintained in suspension in the presence of rhIL-3 (100 units/ml) incorporated up to 12 times more [3H]thymidine than basophils in control cultures. Furthermore, after preincubation in vitro with rhIL-3 (100 units/ml) for 30 min, normal blood basophils released 2- to 3-fold more histamine than basophils pretreated with control medium when exposed to various concentrations of an anti-IgE antibody. Together, these results show that rhIL-3 binds to a specific receptor on blood basophils and is a regulator of basophil function.
Valent
P
P
First Medical Department, University of Vienna, Austria.
Besemer
J
J
Muhm
M
M
Majdic
O
O
Lechner
K
K
Bettelheim
P
P
D000911:Antibodies, Monoclonal; D001491:Basophils / Q000276:immunology*; D001667:Binding, Competitive; D003115:Colony-Stimulating Factors / Q000494:pharmacology; D004261:DNA Replication / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000494:pharmacology; D006636:Histamine Release / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000494:pharmacology; D007377:Interleukin-3 / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D011971:Receptors, Immunologic / Q000502:physiology*; D016185:Receptors, Interleukin-3; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D003115:Colony-Stimulating Factors; D006133:Growth Substances; D007376:Interleukin-2; D007377:Interleukin-3; D011971:Receptors, Immunologic; D016185:Receptors, Interleukin-3; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor