mRNAs encoding CCKB but not CCKA receptors are expressed in human T lymphocytes and Jurkat lymphoblastoid cells.
We previously reported the existence of pharmacologically related gastrin/CCKB type receptors (CCKB-R) in a variant of Jurkat T lymphoblastoid cells (JK(CD3- CD4+)). We studied here the expression of mRNAs encoding CCKA and CCKB receptors in various human white cells by means of Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Using CCKB-R specific primers, we detected a significant expression of CCKB-R mRNA in JK(CD3- CD4+) cells. These transcripts were also expressed, at a lower level, in two other Jurkat clones (JK(CD3+ CD4-) and JK(CD3+ CD4+)), in peripheral blood lymphocytes (PBL) and in purified CD4+ and CD8+ lymphocytes. Activation of Jurkat cells and PBL by T cells mitogenic lectins (jacalin, phytohemaglutinin) did not modify CCKB-R mRNA expression. In all these cells, using CCKA-R specific primers, we could not amplify any specific cDNA fragment corresponding to this receptor. Neither CCKB-R nor CCKA-R mRNAs could be detected in monocytic cells. Our data show for the first time a constitutive expression of CCKB-R transcripts in lymphoid cells. Moreover, the modulation of immunocyte functions by cholecystokinin-related peptides could occur through CCKB-R rather than CCKA-R and affect lymphocytes rather than monocytes.
Cuq
P
P
Laboratoire de Biochimie des Membranes, Faculté de Pharmacie, Montpellier, France.
Gross
A
A
Terraza
A
A
Fourmy
D
D
Clerc
P
P
Dornand
J
J
Magous
R
R
D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D005434:Flow Cytometry; D006801:Humans; D007369:Interferon Inducers / Q000494:pharmacology*; D019169:Jurkat Cells; D037102:Lectins / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D037121:Plant Lectins; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000235:genetics*; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*
D017252:CD3 Complex; D015704:CD4 Antigens; D007369:Interferon Inducers; D037102:Lectins; D010835:Phytohemagglutinins; D037121:Plant Lectins; D012333:RNA, Messenger; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; C043696:jacalin