M, resulting in altered adhesive properties [14]. As we did not find any significant differences in quantity or localization of H. pylori, we do not think that Ctsz and H. pylori compete for binding sites or interact to constrain binding of H. pylori. It is Peptide M biological activity questionable if the human processes outlined above can be transferred to the mouse. At this point, no conclusion can be drawn regarding the interaction of Ctsz and H. pylori at sites of integrin binding. This needs to be further analyzed in primary human cell cultures. Since we found the upregulation of Ctsz to correlate with the severity of gastric injury, starting with mild gastritis up to intestinal cancer, a significant decrease of inflammation and epithelial defects was postulated for H. pylori-infected ctsz2/2 cells [11,12]. As the contrary is true, the following question arises: which is the mechanism behind the ability of Ctsz-deficiency to upregulate macrophage infiltration and metaplastic transition. Similarly unexpected findings were published for MMP-7. The authors suggested that knockout of MMP-7 should decrease the inflammatory response to H. pylori but, in fact, MMP-7 deficiency enhanced the Th-1 and MedChemExpress BIBS39 Th17-mediated responses after H. pylori SS1 infection. They postulated an inability of mmp-72/2 mice to establish proper chemoattractant gradients, thus preventing transepithelial migration of immune cells, manifesting in increased inflammation [7]. Such an explanation could also apply to CtszCathepsin X and Premalignant Host Responsewith the restriction that macrophages, not B- or T-cells, infiltrated knockout mice more strongly (data not shown). The induction of different cytokines in ctsz2/2 mice tends to be stronger and remains stable over a long period of time, although in wt mice, only insufficient induction was seen at 36 and 50 wpi. CXCL1/ KC, MCP-1, and IL-6 are known to strengthen neutrophil chemoattractant activity, recruitment of monocytes, memory T cells, and differentiation of B-cells, respectively. Their long-lasting increase could explain the scores of infiltrating macrophages at 50 wpi in ctsz2/2 mice. Anyway, levels of lymphocytes and granulocytes are indistinguishable in infected wt and ctsz2/2 stomachs (data not shown). This was the second unexpected finding because Ctsz has been described to promote T-cell migration by cleaving the b2 cytoplasmic tail of LFA-1 (lymphocyte function-associated antigen) [19]. In this context, it is questionable if in rodents the functions of LFA-1 are similar to those in humans. CD11a-deficient mice showed normal responses to systemic infections [31]. Furthermore, in contrast to human CD4+ cells, primary murine CD4+ T cells were resistant to treatment with H. pylori harboring the vacA gene with an m1 allele. This effect could be abrogated by expression of human LFA-1 in the murine Tcells [32]. A recent study has demonstrated a causal relationship between epithelial polarity and proliferation control. In polarized epithelial cells, CagA-driven ERK signals prevent p21Waf1/Cip1 expression and induced mitogenesis. In nonpolarized epithelial cells, ERK activation results in oncogenic stress, up-regulation of p21Waf1/Cip1 cyclin-dependent kinase inhibitor, and induction of senescence [33]. Accelerated cellular senescence has also been described in Ctsz-deficient murine embryonic fibroblasts or siRNA-transfected human dermal fibroblasts accompanied by increased expression levels of p21 [34]. These findings are in line with ours.M, resulting in altered adhesive properties [14]. As we did not find any significant differences in quantity or localization of H. pylori, we do not think that Ctsz and H. pylori compete for binding sites or interact to constrain binding of H. pylori. It is questionable if the human processes outlined above can be transferred to the mouse. At this point, no conclusion can be drawn regarding the interaction of Ctsz and H. pylori at sites of integrin binding. This needs to be further analyzed in primary human cell cultures. Since we found the upregulation of Ctsz to correlate with the severity of gastric injury, starting with mild gastritis up to intestinal cancer, a significant decrease of inflammation and epithelial defects was postulated for H. pylori-infected ctsz2/2 cells [11,12]. As the contrary is true, the following question arises: which is the mechanism behind the ability of Ctsz-deficiency to upregulate macrophage infiltration and metaplastic transition. Similarly unexpected findings were published for MMP-7. The authors suggested that knockout of MMP-7 should decrease the inflammatory response to H. pylori but, in fact, MMP-7 deficiency enhanced the Th-1 and Th17-mediated responses after H. pylori SS1 infection. They postulated an inability of mmp-72/2 mice to establish proper chemoattractant gradients, thus preventing transepithelial migration of immune cells, manifesting in increased inflammation [7]. Such an explanation could also apply to CtszCathepsin X and Premalignant Host Responsewith the restriction that macrophages, not B- or T-cells, infiltrated knockout mice more strongly (data not shown). The induction of different cytokines in ctsz2/2 mice tends to be stronger and remains stable over a long period of time, although in wt mice, only insufficient induction was seen at 36 and 50 wpi. CXCL1/ KC, MCP-1, and IL-6 are known to strengthen neutrophil chemoattractant activity, recruitment of monocytes, memory T cells, and differentiation of B-cells, respectively. Their long-lasting increase could explain the scores of infiltrating macrophages at 50 wpi in ctsz2/2 mice. Anyway, levels of lymphocytes and granulocytes are indistinguishable in infected wt and ctsz2/2 stomachs (data not shown). This was the second unexpected finding because Ctsz has been described to promote T-cell migration by cleaving the b2 cytoplasmic tail of LFA-1 (lymphocyte function-associated antigen) [19]. In this context, it is questionable if in rodents the functions of LFA-1 are similar to those in humans. CD11a-deficient mice showed normal responses to systemic infections [31]. Furthermore, in contrast to human CD4+ cells, primary murine CD4+ T cells were resistant to treatment with H. pylori harboring the vacA gene with an m1 allele. This effect could be abrogated by expression of human LFA-1 in the murine Tcells [32]. A recent study has demonstrated a causal relationship between epithelial polarity and proliferation control. In polarized epithelial cells, CagA-driven ERK signals prevent p21Waf1/Cip1 expression and induced mitogenesis. In nonpolarized epithelial cells, ERK activation results in oncogenic stress, up-regulation of p21Waf1/Cip1 cyclin-dependent kinase inhibitor, and induction of senescence [33]. Accelerated cellular senescence has also been described in Ctsz-deficient murine embryonic fibroblasts or siRNA-transfected human dermal fibroblasts accompanied by increased expression levels of p21 [34]. These findings are in line with ours.