ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
In the murine cell line LBRM-331A5, phytohemagglutinin (PHA) induces secretion of the T cell growth factor interleukin 2 (IL2). IL1 augments PHA-induced IL2 production. In this cell line, PHA stimulates a number of biochemical changes including phospholipid hydrolysis, increases in cytosolic free calcium ([Ca2+]i), membrane hyperpolarization, cytosolic alkalinization, and tyrosine phosphorylation of specific substrates. Using LBRM cells, we have studied the interrelationship between these events and the secretion of IL2. Increases in [Ca2+]i triggered by PHA or following addition of ionomycin result in membrane hyperpolarization but are not required for PHA-induced cytosolic alkalinization or tyrosine phosphorylation. Addition of IL1 to PHA-stimulated cells did not affect any of the biochemical parameters, although it significantly augmented PHA-induced IL2 secretion. Increasing [Ca2+]i with ionomycin did not trigger IL2 secretion, increases in cytosolic pH, or tyrosine phosphorylation in the presence or absence of IL1. Preventing increases in cytosolic pH did not alter PHA-induced changes [Ca2+]i in or membrane potential. These data are compatible with PHA including activation of phospholipase C and production of inositol phosphates resulting in both release of Ca2+ from internal stores and transmembrane uptake of Ca2+ as well as activation of protein kinase C. However, unlike other growth factor or mitogen-stimulated systems, the changes stimulated by PHA and IL1 in LBRM cells including IL2 secretion are not regulated by a pertussis toxin-sensitive G protein.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041420313
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