IL6 and infection: When the expression of interleukin 6 (IL-6) was measured, a statistically significant higher expression was observed for the three serotypes studied at both times of infection compared with the control condition (p < 0.0001); at 2 h, a statistically significant higher expression for serotype c was observed compared to the other two serotypes (p < 0.0001), and for serotype b over the serotype a (p < 0.0001).