Preimmune gene refers to a gene that is expressed before exposure to an antigen, indicating that it is involved in immune function. Synonyms for preimmune gene include basal gene, constitutively expressed gene, and innate immunity gene. Basal gene refers to genes that are expressed at low levels in all cells regardless of their specific functions. Constitutively expressed gene describes genes that are expressed constantly in a cell unlike inducible genes that are only expressed in response to a particular stimulus. Innate immunity genes are those that encode proteins involved in the innate immune response. Synonyms for preimmune gene all refer to the gene's ability to respond to antigens and contribute to immunity.