We have compared by reverse phase HPLC the set of peptides eluted from HLA class I molecules in resting and activated CD4+ Jurkat cells. Two peptides were identified that are presented de novo upon activation. After sequencing, one of these peptides turned out to derive from IL-1R antagonist (IL-1Ra). In keeping with this observation, we found that activated, but not resting, Jurkat cells express IL-1Ra. These data indicate that activation of a CD4+ T cell line may result in presentation of peptides derived from proteins expressed de novo after activation. Since IL-1 Ra was not known to be expressed by cells of the T lineage, we also investigated its pattern of expression in normal T lymphocytes. Reverse transcriptase-PCR analyses allowed us to demonstrate that IL-1Ra is expressed upon activation by normal CD4+ lymphocytes from peripheral blood and by thymocytes, but not by CD8+ T cells. Interestingly, of the two forms of IL-1Ra that have been detected in different cell lineages, the intracellular one and the secreted one, only the former is expressed by activated CD4+ T cells.
|Number of pages||7|
|Journal||Journal of Immunology|
|Publication status||Published - Dec 15 1997|
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