Figure 2.

Autoantigen-induced expansion of CD4⁺ T cells is defective in miR-155–deficient mice. (A) LN and spleen cells from unimmunized mice, or from WT or miR-155^−/− mice 21 days after immunization with IRBP were cultured with or without IRBP, and lymphocyte proliferative responses were assessed by the thymidine incorporation assay. (B) Eight-week-old WT or miR-155^−/− mice were euthanized and LN or spleen was harvested. Picture and graph illustrate differences in size and weight of these tissues following immunization of the two mouse strains with IRBP/CFA. (C) Left: CD4⁺ T cells isolated from the spleen and LN of mice described in (A). Right: total lymphocytes isolated for LN of mice were quantified on a Vi-CELL Cell Viability Analyzer (Beckman Coulter, Inc., Sykesville, MD). Data represent at least 3 independent experiments. Statistical significance was determined using Student's t-test (*P < 0.05, **P < 0.01).