Provided are a composition and a food or drink, having the effect of enhancing an immune response to an antigen, which is administered by another route such as subcutaneous injection, by orally administering to a subject, lactic acid bacteria, a culture thereof, a treated product thereof, or a composition comprising the same.An oral ingestion composition, which comprises a lactic acid bacterium strain that is Lactococcus lactis subsp. lactis enhancing the proliferation of cytotoxic T lymphocytes (CTL) and the generation of antibodies, or a culture or treated product thereof, and is used in combination with an antigen as a vaccine, wherein the oral ingestion composition is for use in enhancing the proliferation of cytotoxic T lymphocytes (CTL) specific to the antigen and the generation of antibodies specific to the antigen.
