Intranasal co-delivery of IL-6 gene enhances the immunogenicity of anti-caries DNA vaccine.
OBJECTIVE
To investigate the effects of co-delivering IL-6 expressing plasmid pCI-IL-6 on the immunogenicity of the anti-caries DNA vaccine pCIA-P, which encodes the surface protein antigen PAc of Streptococcus mutans.


METHODS
Plasmid pCI-IL-6 was constructed by inserting the murine IL-6 gene into the pCI vector. Expression of IL-6 in vitro was assessed using Western blot analysis. BALB/c mice were intranasally co-immunized with pCIA-P plus pCI-IL-6 on d 0 and 14. Anti-PAc IgG and secretory IgA (sIgA) were assessed by ELISA. Splenocytes from the mice were re-stimulated with the PAc protein, and IFN-γ and IL-4 production was measured using ELISA. Splenocyte proliferation was analyzed with flow cytometry. Rats were similarly immunized, and dental caries scores were determined using the Keyes method.


RESULTS
Marked expression of IL-6 was found in COS-7 cells transfected with pCI-IL-6. In the pCI-IL-6 co-immunized mice, the specific IgG antibodies in serum and sIgA antibodies in saliva were significantly higher than those in the control mice at weeks 4 and 8. Moreover, the secretion of IFN-γ from splenocytes in response to re-stimulation with PAc protein was significantly higher in the pCI-IL-6 co-immunized mice than that in the control mice, whereas the secretion of IL-4 had no significant difference. The proliferation of splenocytes from the pCI-IL-6 co-immunized mice was significantly higher than that from the mice immunized with pCIA-P and pCI vector. In the rat caries model, the pCI-IL-6 co-immunization rats displayed lower caries scores than the control rats.


CONCLUSIONS
Intranasal co-delivery of IL-6 gene significantly enhances the immunogenicity of the anti-caries DNA vaccine.
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine of Ministry of Education (KLOBM), School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
Ling-kai
LK
Su
Center of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Fei
F
Yu
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine of Ministry of Education (KLOBM), School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
Zhao-fei
ZF
Li
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine of Ministry of Education (KLOBM), School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
Chang
C
Zeng
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine of Ministry of Education (KLOBM), School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
Qing-an
QA
Xu
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine of Ministry of Education (KLOBM), School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
Ming-wen
MW
Fan
D000281:Administration, Intranasal; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000917:Antibody Formation / Q000235:genetics* / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D019556:COS Cells; D002460:Cell Line; D049109:Cell Proliferation; D002522:Chlorocebus aethiops; D003731:Dental Caries / Q000276:immunology*; D005260:Female; D005822:Genetic Vectors / Q000235:genetics / Q000276:immunology; D007114:Immunization / Q000379:methods; D007071:Immunoglobulin A, Secretory / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D015850:Interleukin-6 / Q000235:genetics* / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D012463:Saliva / Q000276:immunology; D013295:Streptococcus mutans / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics* / Q000276:immunology*
D000907:Antibodies, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D007071:Immunoglobulin A, Secretory; D015850:Interleukin-6; D019444:Vaccines, DNA; D015847:Interleukin-4; D007371:Interferon-gamma