Visualization of cholecystokinin receptors on a subset of human monocytes and in rat spleen.
Direct radioreceptor binding experiments and Scatchard analysis reveal CCK receptors on elutriator purified human peripheral blood monocytes, but not on purified human T cells. The monocyte receptors have a single class of high (0.1 nM) affinity binding sites. A structure-function analysis of monocyte binding by different CCK analogs correlates well with previously demonstrated chemotactic responses in monocytes and receptors in brain tissue. Biochemical cross-linking indicates that the monocyte CCK recognition molecule is comparable in molecular size to that in brain membranes. Utilizing a novel fluoresceinated Texas Red-CCK conjugate we have visualized that up to 20% of human peripheral monocytes bear receptors for CCK. A discrete and anatomically significant distribution of CCK receptors in rat spleen is shown by film autoradiography of tissue sections. A more detailed microscopic analysis identifies a dendritic population of monocyte-derived cells within the periarteriolar lymphocyte sheath (PALS) of the white pulp as the CCK receptor-bearing cell in spleen. The anatomical localization of receptor-bearing cells within the PALS region suggests a role for CCK in the antigen processing and sensitization phases of the immune response via regulatory effects of this peptide on a specific, local macrophage-related cell population.
Sacerdote
P
P
Section on Brain Biochemistry, National Institute of Mental Health, NIH, Bethesda, MD 20892.
Wiedermann
C J
CJ
Wahl
L M
LM
Pert
C B
CB
Ruff
M R
MR
D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D003432:Cross-Linking Reagents; D005456:Fluorescent Dyes; D006651:Histocytochemistry; D006801:Humans; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D009000:Monocytes / Q000737:chemistry*; D011869:Radioligand Assay; D051381:Rats; D011949:Receptors, Cholecystokinin / Q000032:analysis*; D013154:Spleen / Q000737:chemistry* / Q000166:cytology; D013329:Structure-Activity Relationship; D014966:Xanthenes
D003432:Cross-Linking Reagents; D005456:Fluorescent Dyes; D011949:Receptors, Cholecystokinin; D014966:Xanthenes; C034657:Texas red