FIG 2.
Similar levels of invasion of Y. enterocolitica to the MLN occur in neonatal and adult mice early after infection. Neonatal (●) and adult (■) wild-type C57BL/6 mice were orogastrically infected with 5 × 108 CFU Y. enterocolitica. Small intestine with contents, small intestine without contents, and MLN from individual neonates and adults 18 h postinfection were homogenized, and Y. enterocolitica titers were determined as described in Materials and Methods. MLN titers are also shown at 48 h postinfection. Dotted lines represent the limits of detection of Y. enterocolitica CFU. ns, not significant; *, P ≤ 0.05.