Epitope specificity of antibodies raised against enterotoxigenic Escherichia coli CFA/I fimbriae in mice immunized with naked DNA.
The cfaB gene, coding for the CFA/I fimbrial adhesin of enterotoxigenic Escherichia coli (ETEC), was cloned and expressed as a fusion peptide with the glycoprotein D (gD) from herpes simplex virus type 1 (HSV) in the pRE4 eukaryotic expression vector, resulting in the recombinant plasmid pRECFA. All BALB/c mice injected intramuscularly (i.m.) with a single dose (100 micrograms) of the purified plasmid developed antibodies against epitopes found on dissociated CFA/I subunits as well as other homologous ETEC fimbriae. Surface-exposed epitopes found on intact CFA/I fimbriae were also recognized by antibodies derived from DNA immunization, but they did not overlap with those generated with purified CFA/I fimbriae. None of the sera raised in mice immunizated with pRECFA were able to agglutinate bacterial cells or inhibit haemagglutination promoted by CFA/I bearing ETEC cells. These results show that pRECFA can elicit CFA/I-specific antibodies, which may have different epitope specificities and functional properties compared with those generated with purified bacterial protein.
Alves
A M
AM
Laboratório de Fisiologia Celular, Instituto de Biofísica Carlos Chagas Filho, UFRJ-CCS, Cidade Universitária, Rio de Janeiro, Brazil.
Lásaro
M O
MO
Almeida
D F
DF
Ferreira
L C
LC
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology*; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019444:Vaccines, DNA / Q000276:immunology*
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D000939:Epitopes; D019444:Vaccines, DNA; C022924:colonization factor antigens; D036781:Fimbriae Proteins