A recombinant fragment of Helicobacter pylori CagA affects proliferation of human cells.

The outcome of H. pylori infectins depends on proliferation of various host cells, including lymphocytes, monocytes and epithelial cells. In this study we showed that a recombinant fusion protein carrying an immunodominant region of H. pylori CagA antigen affected the proliferation of human cells. The rCagA inhibited PHA-driven T cell proliferation but enhanced the growth of epithelial HeLa cells, especially in the presence of granulocyte macrophage colony stimulating factor (GM-CSF). When THP-1 monocytes and Kato-3 epithelial cells from metastasis of gastric carcinoma were stimulated with GM-CSF, they were also susceptible to the inhibitory effect of rCagA. These results confirmed our earlier suggestion on the inhibition of T cell function by H. pylori CagA protein. However, antiproliferative activity of CagA antigen appears to be not restricted to T lymphocytes but modulatory effect of this protein seems to depend on the cell type.