Oral immunization with recombinant Lactococcus lactis NZ9000 expressing human papillomavirus type 16 E7 antigen and evaluation of its immune effects in female C57BL/6 mice

• Published in: Journal of medical virology Vol. 91; no. 2; pp. 296 - 307
• Main Authors: Mohseni, Amir Hossein, Razavilar, Vadood, Keyvani, Hossein, Razavi, Mohammad Reza, Khavari‐Nejad, Ramazan Ali
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.02.2019
• Subjects: Administration, Oral; Animals; Antibodies; Antibodies, Viral - blood; Anticancer properties; Antigens; Antitumor activity; CD4 antigen; CD8 antigen; Cell culture; Cytokines; Cytokines - blood; Drug Carriers - administration & dosage; Enzyme-Linked Immunosorbent Assay; Enzyme-Linked Immunospot Assay; Enzymes; enzyme‐linked immunospot (ELISPOT); Female; Gene expression; Human papillomavirus; human papillomavirus type 16 (HPV‐16); Immune response (cell-mediated); Immune response (humoral); Immunization; Interferon; Intestine; Lactococcus lactis; Lactococcus lactis - genetics; Lymphocytes; Lymphocytes T; Mice; Mice, Inbred C57BL; Mucosa; Nisin; Optimization; Oral administration; oral immunization; Papillomavirus E7 Proteins - genetics; Papillomavirus E7 Proteins - immunology; Papillomavirus Infections - prevention & control; Papillomavirus Vaccines - administration & dosage; Papillomavirus Vaccines - genetics; Papillomavirus Vaccines - immunology; pNZ8123; Proteins; Splenocytes; T-Lymphocytes - immunology; Tumors; Vaccination; vaccine; Vaccines, Synthetic - administration & dosage; Vaccines, Synthetic - genetics; Vaccines, Synthetic - immunology; Virology; Lactococcus lactis; enzyme-linked immunospot (ELISPOT); oral immunization; vaccine; pNZ8123; human papillomavirus type 16 (HPV-16)
• ISSN: 0146-6615; 1096-9071
• DOI: 10.1002/jmv.25303

The ORFs of both native and codon‐optimized E7 genes were successfully fused to SPusp45 signal peptide and expressed by a nisin‐controlled gene expression system in the NZ9000 strains of Lactococcus lactis. Recombinant strains were confirmed by Western blot analysis. To measure immune responses against the E7 antigen, specific‐pathogen‐free C57BL/6 mice were inoculated with L lactis harboring pNZ8123‐rE7 by oral gavage. Then, specific antibodies and cytokines were measured by enzyme‐linked immunosorbent assay and enzyme‐linked immunospot assay, respectively. Oral administration of L lactis strains expressing rE7 elicited the highest levels of E7‐specific antibody and greatest numbers of E7‐specific CD4+ T helper and CD8+ T cell precursors. Our outcomes indicated that the HPV‐16 E7 specific IL‐2‐ and IFN‐γ‐secreting T cells in antigen‐stimulated splenocytes and intestinal mucosal lymphocytes were significantly higher than the control groups. Our data also demonstrated that mice vaccinated with recombinant L lactis were able to generate potent protective effects against challenge with the E7‐expressing tumor cell line (TC‐1). Moreover, L lactis containing pNZ8123‐HPV16‐optiE7 showed strong therapeutic antitumor effects against established tumors in vivo. These findings demonstrate that recombinant L lactis induce both humoral and cellular immune responses in mice and are therefore recommended for therapeutic treatments in humans after oral administration. L. lactis system is an appropriate host for the production of recombinant HPV‐16 E7 oncoprotein. Codon optimization, along with optimization of culture condition can enhance the secretion of the rE7 protein. Lactococcus lactis harboring pNZ8123‐HPV16‐optiE7 induced significantly higher percentages of CD4+ and CD8+ cells compared to the L lactis harboring pNZ8123‐HPV16‐E7. Oral immunization of mice with recombinant L lactis NZ9000 expressing human papillomavirus type 16 E7 antigen can effectively stimulate both humoral and cellular immune responses.