Improved humoral immunity against tuberculosis ESAT-6 antigen by chimeric DNA prime and protein boost strategy.
Ag85A and ESAT-6 proteins of Mycobacterium tuberculosis (M.TB) are important protective antigens. The 32-kDa Ag85A is a strong immunogen in both small and large animals. However, the 6-kDa ESAT-6 has relatively low inherent immunogenicity, especially in large animals. To improve the immunogenicity of ESAT-6 in animals, we made chimeric DNA vaccines, HG856K and HG856A, by inserting the esat-6 gene into the Kpn I or Acc I endonuclease restriction site of the ag85a gene, respectively. BALB/c mice were injected intramuscularly three times with the 10-microg singular DNA vaccine (HG85 encoding for Ag85A or HG6 encoding for ESAT-6) or chimeric DNA vaccine (HG856K or HG856A) followed by electroporation (EP). Ten days after the last DNA vaccination, mice received a booster immunization intraperitoneally with 50-microg pure recombinant protein Ag85A or ESAT-6 without adjuvant. Additional groups of mice immunized with chimeric DNA vaccines were boosted with two mixed proteins (Ag85A/ESAT-6) at the same time. The results showed that the immunogenicity of M.TB ESAT-6 antigen was not improved by priming with the HG6 DNA vaccine. However, the humoral immunity against the ESAT-6 antigen was significantly increased in the mice primed with chimeric DNA vaccines, HG856K or HG856A, followed by boosting with ESAT-6 or ESAT-6/Ag85A mixed proteins.
Li
Zhongming
Z
Vaccine Research Laboratory, Shanghai H&G Biotechnology Co. Inc., People's Republic of China. zhongmingli1946@yahoo.com
Song
Dan
D
Zhang
Hongyong
H
He
Wei
W
Fan
Xiaoyong
X
Zhang
Ying
Y
Huang
Jialu
J
Wang
Xiaoyi
X
Liu
Qingliang
Q
Xiong
Sidong
S
D000217:Acyltransferases / Q000235:genetics / Q000276:immunology; D000818:Animals; D000917:Antibody Formation; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins; D005260:Female; D007117:Immunization, Secondary; D051379:Mice; D008807:Mice, Inbred BALB C; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D032581:Tuberculosis Vaccines / Q000235:genetics / Q000276:immunology*; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D032581:Tuberculosis Vaccines; D019444:Vaccines, DNA; D000217:Acyltransferases; C112580:antigen 85A, Mycobacterium tuberculosis