Immunization against the colonization factor antigen I of enterotoxigenic Escherichia coli by administration of a bivalent Salmonella typhimurium aroA strain.
An expression plasmid (pCFA-1) carrying the cfaB gene that codes for the enterotoxigenic Escherichia coli (ETEC) fimbrial adhesin colonization factor antigen I (CFA/I) subunit was constructed and used to transform a derivative of the attenuated Salmonella typhimurium aroA vaccine strain SL3261 carrying an F'lacIq. Treatment of the transformed strain with isopropyl-beta-D-thiogalactopyranoside (IPTG) resulted in elevated in vitro expression of the CFA/I subunit. Although flagellar function and lipopolysaccharide (LPS) synthesis were similar in both the parental and the recombinant strains, spleen colonization was reduced in the recombinant strain. All BALB/c mice parenterally inoculated with the recombinant strain developed significant anti-CFA/I and anti-LPS serum antibody titers (P < 0.05). Moreover, 2 of 5 mice orally inoculated with the engineered Salmonella strain developed anti-CFA/I intestinal IgA (P > 0.05) while 4/5 of the same mice developed anti-LPS IgA (P < 0.05). The results indicate that the vaccine strain elicited an antibody response against the bacterial host both after oral and intravenous immunization while the response against the CFA/I antigen was significant only after inoculation by the intravenous route.
Laboratório de Fisiologia Celular, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brasil.
H C
HC
Guillobel
M G
MG
Luna
E F
EF
Camacho
D F
DF
Almeida
L C
LC
Ferreira
D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D003967:Diarrhea / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D004927:Escherichia coli Infections / Q000517:prevention & control*; D022361:Escherichia coli Vaccines; D036781:Fimbriae Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D012486:Salmonella typhimurium / Q000276:immunology*; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D022361:Escherichia coli Vaccines; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; C022924:colonization factor antigens; D036781:Fimbriae Proteins