ICAM1 and infection: Regarding the expression levels of ICAM-1 in response to infection with A. actinomycetemcomitans, all the serotypes studied were capable of inducing a statistically significant increase in the expression of this molecule compared to the non-stimulated condition, serotype a (p = 0.0035), b (p < 0.00201), and c (p = 0.0011) at 2 h of infection, and serotype a (p < 0.0001), b (p < 0.0001), and c (p < 0.0001) at 24 h of infection (Figure 8B).