**8. Immune response role of antibodies in protective immunity**

Analogy with other mucosal pathogens was originally thought to be primarily antibodies to mediate a defensive immune reaction against *H. pylori*. Subsequent studies found that the importance of the humoral immunity mechanism is negligible. Antibodies can prevent infection successfully and decrease the colonization in animal models studies [145]. *H. pylori* infection results in an induction of a Th1-polarized response that does not result, however, in clearance of the infection. This is striking, because the primary function in sterilizing Immunity is stated to be cellular rather than humoral immunity [146], Although it is now widely agreed that *H. pylori*-induced gastritis and/or pathology primarily rely on Th1 cells and Th1 cytokines [147]. While a polarized Th2 reaction defends against this pathology, it doesn't generally include the defense of Th2 cells after immunization. In fact, Th1-polarized T cells recruit mononuclear cells to the infection site instead of Th2 polarized, thereby removing bacteria [148].
