Answer: B) S. typhimuium gains access to the host by crossing the intestinal epithelium inside M cells The M cells are found in the gut-associated lymphoid tissue (GALT) of the Peyer\'s patches and in the mucosa-associated lymphoid tissue (MALT) of other parts of the gastrointestinal tract. These cells are known to initiate mucosal immunityresponses on the apical membrane of the M cells and allow for transport of microbes and particles across the epithelial cell layer from the gut lumen to the lamina propria where interactions with immune cells can take place. M cells have the unique ability to take up antigen from the lumen of the small intestine via endocytosis, phagocytosis, or transcytosis. Solution Answer: B) S. typhimuium gains access to the host by crossing the intestinal epithelium inside M cells The M cells are found in the gut-associated lymphoid tissue (GALT) of the Peyer\'s patches and in the mucosa-associated lymphoid tissue (MALT) of other parts of the gastrointestinal tract. These cells are known to initiate mucosal immunityresponses on the apical membrane of the M cells and allow for transport of microbes and particles across the epithelial cell layer from the gut lumen to the lamina propria where interactions with immune cells can take place. M cells have the unique ability to take up antigen from the lumen of the small intestine via endocytosis, phagocytosis, or transcytosis..