TECHNICAL FIELD The present invention relates to a lactic acid bacterium preparation containing Leuconostoc mesenteroides strain NTM 048 strain or a mutant strain thereof or a bacterial cell treated product thereof, a bacterial strain thereof or a treated product thereof, which has been deposited under the deposit number NITE BP-1519, Provide immunity (particularly intestinal immunity) activator.本発明は、受託番号NITE BP-1519で寄託されている、ロイコノストック メセンテロイデス(Leuconostoc mesenteroides)NTM048株もしくはその変異株又はその菌体処理物、該菌株又はその菌体処理物を含む乳酸菌製剤、免疫(特に腸管免疫)賦活剤を提供する。