English: The arginase inhibitor BEC prevents larval immobilization during challenge infection in vivo. C57BL/6 mice were treated with S-(2-boronoethyl)-L-cysteine (BEC) (0.2%, 100 µl by oral gavage) during challenge Hp infection. Mice were sacrificed on day 4 p.i. and small intestines were removed. Pieces of the upper duodenum were carefully covered with cover slips and time lapse-movies were immediately recorded with an Olympus AX70 microscope. Movies were processed using iMovie software. Representative examples are shown.