International Immunology, Vol. 11, No. 2, 125-132,
February 1999
© 1999 Japanese Society for Immunology
Autoreactive human T cell lines recognizing ribosomal protein L7
Faculty of Biology, University of Konstanz, 74857 Konstanz, Germany
1 Department of Rheumatology and Clinical Immunology, University Hospital, Hugstetterstrasse 55, 79106 Freiburg, Germany
Correspondence to: J. Donauer, Department of Nephrology, University Hospital Freiburg, Hugstetterstrasse 55, 79106 Freiburg, Germany
Sera of patients suffering from systemic lupus erythematosus (SLE) frequently contain oligoclonal IgG autoantibodies with high affinity for the ribosomal protein L7 (rpL7). The humoral autoimmune response to rpL7 apparently is driven by antigen and T cell dependent. In order to analyze the T cell response to rpL7 we cultured peripheral blood lymphocytes of healthy individuals and SLE patients in the presence of recombinant rpL7. After 10 days, the cytokine response to re-stimulation with rpL7 was examined using a spot-ELISA. Measuring IFN-
secretion, the T cells of two patients and four healthy donors showed a significant increase in the number of spots as compared to control cells. Secretion of IL-4 or IL-10 was not detected. From the antigen-stimulated primary cultures we established by limiting dilution cloning six rpL7-reactive, IFN-
-secreting T cell lines which show a CD3+CD4+CD8 phenotype. One line additionally was shown to be positive for HLA-DR and CD45R0, but negative for CD27 and CD31. The cell lines carry
ß TCR chains which differ from each other in sequence and specificity. rpL7 fragments rich in basic amino acids could be identified as epitopes recognized by the TCR of three cell lines. Recognition of rpL7 is HLA-DR6 restricted or respectively HLA-DP restricted in the two cell lines analyzed.
Keywords: autoreactivity, human T cells, ribosomal protein L7