CD28 and infection: Restimulation of mesenteric lymph node (mLN) cells 21 days post-infection (p.i.)with anti-CD3/CD28 induces the production of type-2 cytokines, such as IL-4, IL-5, and IL-13, in cells derived from WT mice but not in A20myel-KO mLN cells (Figure 2E).