The human mast cell line HMC-1 expresses C5a receptors and responds to C5a but not to C5a(desArg).
The expression of the receptor for the anaphylatoxin C5a (C5aR, CD88) on the human mast cell line HMC-1 was studied with four anti-C5aR monoclonal antibodies directed to the N-terminal domain of the receptor. All antibodies bound to the human mast cell line HMC-1. The binding could be blocked by recombinant C5a and by peptide EX-1 representing amino residues 1-31 on the N-terminal domain of the C5aR. In addition, FITC-labelled C5a bound to HMC-1, and this binding could be blocked by unlabelled C5a or C5aR antibodies. C5aR-specific mRNA was detected in HMC-1 cells by RT-PCR which confirmed the expression of the C5aR gene made by these cells. Lymphocyte-conditioned medium, interferon-gamma or phorbol esters which have been shown to induce a down-regulation of C5aR on myeloid cells did not influence the expression of C5aR on HMC-1. C5a led to a transient mobilization of intracellular calcium in HMC-1 which could be inhibited by pre incubation of C5a with a C5a-specific antibody. In contrast to findings with granulocytes, HMC-1 did not respond to C5a(desArg), confirming previous findings with human skin mast cells. The findings show that (i) although HMC-1 differ from granulocytes in their responsiveness to C5a(desArg), they express similar C5aR and (ii) HMC-1 cells resemble skin mast cells in the expression and function of C5aR and may therefore serve as a model in future studies addressing the biology of this anaphylatoxin receptor on skin mast cells.
Werfel
T
T
Dermatologische Klinik und Poliklinik der Medizinischen Hochschule, Hannover, Germany.
Oppermann
M
M
Butterfield
J H
JH
Begemann
G
G
Elsner
J
J
Götze
O
O
Zwirner
J
J
D000911:Antibodies, Monoclonal / Q000737:chemistry; D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D001666:Binding Sites, Antibody; D015936:Complement C5a / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D015937:Complement C5a, des-Arginine / Q000502:physiology*; D006801:Humans; D007946:Leukemia, Mast-Cell / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015937:Complement C5a, des-Arginine; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D015936:Complement C5a