Unique pattern of cleavage of vasoactive intestinal peptide by human lymphocytes.
Human cultured T lymphocytes of the Jurkat line and myeloma cells of the U266 line cleaved the 28 amino acid vasoactive intestinal peptide (VIP1-28) preferentially at three sites with time- and temperature-dependence. The fragments VIP4-28 and VIP23-28) from an endopeptidase activity, and VIP15-28 from a trypsin-like peptidase, together represented a range of 26-65% of the VIP1-28 recovered after 2 hr at 37 degrees C or 4 hr at 22 degrees C, based on the absorbance of purified peptides and the radioactivity of [125I]Tyr10 VIP1-28. The endopeptidase activity was associated with membranes recovered after disruption of U266 cells by nitrogen cavitation. Pretreatment of intact U266 and Jurkat cells with diisopropylfluorophosphate (DFP) and the subsequently isolated subcellular particles with phenylmethylsulphonylfluoride (PMSF) and leupeptin inhibited the trypsin-like enzyme by a mean of 80%, without suppressing endopeptidase activity. In contrast, 0.1 mM DL-thiorphan and phosphoramidon blocked selectively a range of 35-70% of the endopeptidase activity in membrane preparations and intact cells. The capacity of lymphocytes to degrade VIP1-28 may substantially alter the effects of this neuromediator on functions of some subsets of T and B cells.
Goetzl
E J
EJ
Howard Hughes Medical Institute, San Francisco, CA 94143-0724.
Kodama
K T
KT
Turck
C W
CW
Schiogolev
S A
SA
Sreedharan
S P
SP
D001402:B-Lymphocytes / Q000201:enzymology*; D002460:Cell Line; D010450:Endopeptidases / Q000502:physiology*; D006801:Humans; D010446:Peptide Fragments; D013601:T-Lymphocytes / Q000201:enzymology*; D014660:Vasoactive Intestinal Peptide
D010446:Peptide Fragments; D014660:Vasoactive Intestinal Peptide; D010450:Endopeptidases