CD4 and Arthritis: Compensating for the reduction in the total frequency of CII-specific T cells from day 10 onwards (Figure 5a), however, showed that the frequency of IL-2-producing and IFNγ-producing T cells among CD4+ T cells was highest at the priming phase (day 10) and then decreased with the progressing arthritis in both B22a1+ and B22a1- CD4+ T cells (data not shown).