Figure 4. L. braziliensis infection prevents the upregulation of IFN-inducible genes due to SGS pre-immunization.

BALB/c mice were inoculated 3 times in the right ear pinna every 2 wks with Lu. intermedia SGS and then challenged in the left ear 2 wks later with Lu. intermedia SGS plus 1×10⁶ L. braziliensis stationary phase promastigotes. The left ears were collected 2 wks after infection, homogenized and the expression of IFN-inducible genes such as (A) Ifit1, Irgm1 and Irgm2, and the expression of IFN-related genes like (B) Stat1 and CXCL9 was determined by real-time quantitative PCR. Relative mRNA expression normalized to the housekeeping gene HPRT is presented as the mean +SEM (n = 5 mice per group); * p<0.05 by Student's t-test.