Quantification and characterization of ACTH-related peptides produced by human peripheral blood mononuclear cells.
We have used a sensitive radioimmunoassay to quantify and characterize PBMC-associated immunoreactive ACTH (ACTH-IR). Mean ACTH content of freshly isolated human PBMCs was 3.8 +/- 0.72 pg (SEM) per 10(6) cells. During 3 days of incubation ACTH-IR in conditioned media of control PBMCs increased significantly, p less than 0.02. Gel filtration chromatography revealed a minor peak of ACTH-IR coeluting with ACTH (1-39) and a major peak coeluting with ACTH (11-24). Treatment with 15 nM CRH did not alter the amount of ACTH-IR secreted or its gel pattern. Synthetic ACTH (11-24), was radioiodinated and was used for binding experiments that demonstrated specific high- and low-affinity binding sites for ACTH (11-24) on a human T cell line. These results add support for a role of ACTH and related peptides in immune regulatory systems and suggest that cell-specific post-translational processing of POMC may generate an expanding number of biologically active moieties.
Pepper
G M
GM
Long Island Jewish Medical Center, New York, NY 10042.
Maimon
J
J
Schneider
B S
BS
D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis / Q000097:blood*; D000328:Adult; D002457:Cell Extracts / Q000737:chemistry; D002478:Cells, Cultured; D002850:Chromatography, Gel; D003366:Cosyntropin / Q000378:metabolism; D003470:Culture Media; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000378:metabolism; D011863:Radioimmunoassay
D002457:Cell Extracts; D003470:Culture Media; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D003366:Cosyntropin; C034016:ACTH (11-24); D000324:Adrenocorticotropic Hormone