ABSTRACT
Activation of normal human peripheral blood B-enriched lymphocytes with antiserum reacting with membrane immunoglobulin was associated with increased phosphorylation of cellular proteins, particularly in the Triton-insoluble cytoskeletal fraction. At least two proteins (56K and 60K) were labeled predominantly at tyrosine residues. These findings may indicate another specialized membrane structure which upon specific ligand binding stimulates tyrosine phosphorylation in association with cellular proliferation.
Subject(s)
B-Lymphocytes/enzymology , Blood Proteins/metabolism , Protein Kinases/blood , Receptors, Immunologic/immunology , B-Lymphocytes/immunology , Cell Division , Cytoskeleton/analysis , Electrophoresis, Polyacrylamide Gel , Humans , Immune Sera , Magnesium/pharmacology , Manganese/pharmacology , Molecular Weight , Phosphorylation , Protein-Tyrosine KinasesABSTRACT
Forty-one patients with various forms of systemic sclerosis (scleroderma) and positive antinuclear antibodies of nucleolar (ten patients), speckled (eleven patients), or centromere pattern (twenty patients) were selected for study of immune complexes by the radioisotope labeled Clq binding and the radioisotope labeled protein A binding methods. The presence of immune complexes was found by the Clq binding assay in sixteen patients (39%) and by a protein A binding assay in eight patients (20%). Overall, 46% of patients (19/41) had immune complexes. A lower incidence of organ involvement and fewer positive results in the screening of serum immune complexes were observed in patients with centromere antibody (35%) than in patients with nucleolar (60%) or speckled pattern (55%). Patients with immune complexes had higher frequencies of kidney, heart, and muscle involvement and digital ulceration than did patients with no detectable immune complexes, but the differences were not statistically significant. Diffuse skin involvement was not related to the presence of immune complexes.
