Table 1.

Differentiation of CD4⁺ Th cells after infection of IRF4-deficient mice with L. major

Stimulus	IL-2, pg/ml		IL-4, pg/ml		IFN-γ, pg/ml
	IRF4+/−	IRF4−/−	IRF4+/−	IRF4−/−	IRF4+/−	IRF4−/−
Medium	19  ± 5	9  ± 2	<4	<4	180  ± 36	<70
LmAg	60  ± 8	40  ± 17	237  ± 48	<4	12,500  ± 6,600	250  ± 300

IRF4^+/− and IRF4^−/− mice (four per group) were infected with 2 × 10⁷ L. major promastigotes in the right hind footpad. Mice were killed 1 week later and cell suspensions of the popliteal LN of individual mice were restimulated in vitro with LmAg (2). Cytokine production in 24 h culture supernatants was measured by ELISA. Data are the mean concentration of cytokines ± SD for each group of mice. The results are representative of three independent experiments.