Inhibition of protein phosphorylation by synthetic peptides from the Fc region of human IgG during the mixed lymphocyte response
Certain synthetic peptides derived from the Fc region of human IgG suppressed protein, RNA, and DNA synthesis during mixed lymphocyte reactions. Responder mononuclear cells were incubated with medium or agents that alter phosphorylation of cellular proteins before immunomodulatory Fc peptides and stimulator cells were added. Incubating cells with trifluoperazine which inhibits calcium binding to calmodulin and inhibits protein kinase C (PKC) increased inhibition of the MLR induced by Fc peptides. Conversely, incubating cells with dubutyryl cyclic AMP (DBcAMP), calmodulin, 1,2-diolein, or phorbol myristate acetate (PMA) abolished inhibition of the MLR induced by Fc peptides. Inhibition of the MLR by Fc ..gamma.. peptides was not affected when DBcAMP or PMA was added after peptide addition. The PKC activity of cell homogenates was decreased by 69% when Fc..gamma.. peptides were present during the MLR. The in vitro phosphorylation of histone Hl by partially purified PKC from lymphocytes was inhibited 74% in the presence of Fc..gamma.. peptides. These results indicate that suppression of the MLR induced by Fc..gamma.. peptides is dependent on inhibition of protein phosphorylation by kinases including protein kinase C. The inhibition of phosphorylation may be related to the ability of Fc..gamma.. peptides to reverse animal models of autoimmune disease.
- Research Organization:
- Immunetech Pharmaceuticals, San Diego, CA
- OSTI ID:
- 5458218
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
LYMPHOCYTES
CELL PROLIFERATION
PEPTIDES
BIOLOGICAL EFFECTS
PHORBOL ESTERS
PROTEINS
PHOSPHORYLATION
AMP
BIOCHEMICAL REACTION KINETICS
DNA REPLICATION
IMMUNOGLOBULINS
INHIBITION
PHOSPHOTRANSFERASES
RNA
ANIMAL CELLS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARCINOGENS
CHEMICAL REACTIONS
CONNECTIVE TISSUE CELLS
ENZYMES
ESTERS
GLOBULINS
KINETICS
LEUKOCYTES
MATERIALS
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
NUCLEOTIDES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
REACTION KINETICS
SOMATIC CELLS
TRANSFERASES
560201* - Thermal Effects- Cells- (-1987)
550200 - Biochemistry