IFNG and neoplasm: Compared to the L. lactis only expressing E7 antigen vaccinated group, the tumor volume of mice treated with E7 antigen and IL‐12 was significantly smaller, and L. lactis co‐expressing antigen and IL‐12 could further regress tumor growth.[59] Additionally, IL‐12 was expressed by L. lactis to defense Leishmania major infection with LACK antigen.[60, 61] Oral vaccination with LACK and IL‐12 was capable of eliciting the secretion of IgA in intestinal washes and IFN‐γ in splenocytes and mesenteric lymph node cells, indicated eliciting mucosal and systemic Th1 immune response.