Thus, utilization of our isogenic strain collection as a means to remove extraneous H. pylori variables suggests that within the AGS model system, host cell elongation is influenced by polymorphisms in the CagA EPIYA region only early in infection; however, we do note that it may be possible that lack of a difference in host cell elongation at later time points may be due to saturation of the elongation phenotype in the AGS model. This evidence concerns the gene S100A8 and infection.