Pathophysiologial role of Helicobacter pylori asparaginase

幽门螺杆菌门冬酰胺酶通过天冬酰胺剥夺对U937细胞具有显著的细胞毒活性。活H. pylori细胞对U937细胞的杀伤作用因天冬酰胺酶基因的缺失而显著减弱。天冬酰胺酶缺陷的突变株是显着不太能够殖民蒙古沙鼠。H.幽门螺杆菌细胞通过转运由天冬酰胺酶作用产生的天冬氨酸而掺入细胞外天冬酰胺。H.幽门螺杆菌门冬酰胺酶可能参与抑制胃内正常淋巴细胞功能，使H. pylori以逃避宿主免疫系统。

Helicobacter pylori sparaginase exhibited striking cytotoxic activity against U937 cells via asparagine deprivation. The cytotoxic activity of live H. pylori cells against U937 cells was significantly diminished by deletion of the asparaginase gene. An asparaginase-deficient mutant strain was significantly less capable of colonizing Mongolian gerbils. H. pylori cells incorporated extracellular asparagine by transporting aspartate produced by the action of the asparaginase. H. pylori asparaginase may be involved in inhibition of normal lymphocyte function at the gastric niche, allowing H. pylori to evade the host immune system.