Induction of proinflammatory cytokines was assessed using the administration of phosphate-buffered saline or K. septempunctata at 5 × 10⁶ spores/mouse in suckling mice. Tumour necrosis factor (TNFα) (Fig. 6A) and interleukin 6 (IL-6) (Fig. 6B) expression levels were examined by SYBR green quantitative polymerase chain reaction and normalised using β-actin expression as an internal control. Relative levels of immune gene mRNA were analysed by the 2^−ΔCt method (the C_t value of the target immune gene minus the C_t value of the β-actin gene). Data are presented as means ± standard deviation. Hpi: hours post-ingestion.