<；P>；PROBLEM TO BE SOLVED: To provide a method for screening a lactic acid bacterium which has high safety, produces a prophylactic effect by ingestion, and provides immunostimulatory activity which exhibits an effect on any viruses by taking the lactic acid bacterium. <；P>；SOLUTION: Since a lactic acid bacterium selected from among lactic acid bacteria in which the measurements of amount of polysaccharide production exceed a standard level on the basis of the measurements of IFN-&gamma； production-inducing activity of the polysaccharide enables to increase the natural immunity of those who have taken the lactic acid bacterium, it is possible to give a possible prophylactic effect prior to viral infection without exhibiting viral specificity such as in using vaccines. <；P>；COPYRIGHT: (C)2011,JPO&INPIT
