MAPK3 and infection: Besides peptidoglycan [14], OipA [13] and CagA [21], VacA has now also been found to activate pro-inflammatory responses during infection with Hp. For example, addition of VacA to the gastric adenocarcinoma cell line AZ-521 activates two classes of MAP kinases (p38 and Erk-1/2) and the activating transcription factor 2 (ATF-2) signalling pathway [104], (Figure 3B).