Chronic myelogenous leukemia-derived basophilic granulocytes express a functional active receptor for the anaphylatoxin C3a.
The receptor for the inflammatory peptide C3a has scarcely been examined on human cells. This work demonstrates that human tumor-derived basophilic granulocytes express C3a receptors, and presents parts of the hitherto unknown C3a-signal transduction. When incubated with IL-3, these cells specifically liberated histamine on C3a stimulation. Independent from IL-3, 240,000 +/- 100,000 receptors per cell with a Kd of 5.6 +/- 0.9 nM were determined. [Ca2+]i increased from 120 +/- 35 nM to 300 +/- 80 nM after a C3a challenge, as measured by digital imaging fluorescence microscopy, and rested at its basal level in the presence of C3a-desArg, the immediate catabolic product of C3a in vivo. This [Ca2+]i increase could be completely desensitized homologously by C3a as well as inhibited by up to 75% by pertussis toxin. Thus, tumor-derived basophils are suitable for cloning of the human C3a receptor.
Kretzschmar
T
T
Department of Medical Microbiology, Medical School of Hannover.
Jeromin
A
A
Gietz
C
C
Bautsch
W
W
Klos
A
A
Köhl
J
J
Rechkemmer
G
G
Bitter-Suermann
D
D
D000706:Anaphylatoxins / Q000378:metabolism*; D001491:Basophils / Q000378:metabolism*; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D015926:Complement C3a / Q000031:analogs & derivatives / Q000378:metabolism*; D015936:Complement C5a / Q000378:metabolism; D006636:Histamine Release; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism*; D011951:Receptors, Complement / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction
D000706:Anaphylatoxins; D007377:Interleukin-3; D011951:Receptors, Complement; D011994:Recombinant Proteins; C044541:complement C3a, des-Arg-(77)-; D015926:Complement C3a; D015936:Complement C5a; D002118:Calcium