A secreted peptidase involved in T cell β-endorphin metabolism

• Published in: Immunopharmacology 1996-03, Vol.31 (2-3), p.151-161
• Main Authors: Miller, B.C., Thiele, D., Hersh, L.B., Cottam, G.L.
• Format: Article
• Language: English
• Subjects: AIDS/HIV; Amino Acid Sequence; Analysis of the immune response. Humoral and cellular immunity; Animals; beta-Endorphin - metabolism; Biological and medical sciences; Camelus; CD4-Positive T-Lymphocytes - chemistry; CD4-Positive T-Lymphocytes - enzymology; CD4-Positive T-Lymphocytes - secretion; CD8-Positive T-Lymphocytes - chemistry; CD8-Positive T-Lymphocytes - enzymology; CD8-Positive T-Lymphocytes - secretion; Cells, Cultured; Endopeptidases - chemistry; Endopeptidases - physiology; Endopeptidases - secretion; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunobiology; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Molecular Sequence Data; Organs and cells involved in the immune response; Sulfhydryl Compounds - metabolism; T cell peptidase; Thymoma; Tumor Cells, Cultured; β-Endorphin metabolism; γ-Endorphin
• ISSN: 0162-3109
• DOI: 10.1016/0162-3109(95)00046-1

β-endorphin metabolism by CD4+ and CD8+ T cells, and the thymoma cell line, EL4, was investigated. In all three cell types, extracellular β-endorphin was metabolized exclusively by a secreted, metal-dependent, thiol peptidase. The enzyme activity is expressed constitutively in EL4 cells and following activation of CD4+ and CD8+ T cells with anti-CD3 antibody. The enzyme is not one of the proteinases associated with cytolytic T cells and does not appear to be identical with any previously described β-endorphin metabolizing enzyme. The enzyme cleaves β-endorphin at approximately equal rates at either of two sites to yield β-endorphin1–17 (which is γ-endorphin), β-endorphin1–18, β-endorphin18–31 and β-endorphin19–31. Evidence in the literature indicates that these N- and C-terminal peptides which contain, respectively, the opioid and non-opioid receptor binding domains of β-endorphin, are biologically active. Thus, it is likely that this new T cell peptidase has important immunoregulatory activity.