Limiting dilution analysis of interleukin 2 and colony-stimulating factor producer cells in normal and autoimmune mice.

MRL/MP lpr-lpr (MRL-lpr) mice spontaneously develop an age-related disease characteristic of human systemic lupus erythematosus (SLE). Old MRL-lpr mice (4 mo of age) develop antibodies to nucleic acids, display immune complex glomerulonephritis, and have a massive T cell-associated lymphadenopathy. In concert with disease development is data showing an age-related loss of interleukin 2 (IL 2) production by mitogen-stimulated lymphoid cells from these mice. The loss of IL 2 production has been suggested to be involved in the onset and/or development of autoimmune disease seen in these animals. In this report, we examined the frequency of both IL 2 and colony-stimulating factor (CSF) producer T cells in the MRL-lpr mouse by using a limiting dilution analysis assay. Our results show that the number of IL 2 and CSF producer cells present in autoimmune animals is similar to the number found in normal control mice. In addition, IL 2 and CSF producer T cells from autoimmune MRL-lpr mice make similar levels of lymphokine activity, as do producer T cells from normal mice. Our data argue against the previously hypothesized role that a paucity of IL 2 production may be involved in the etiology of autoimmune disease.