Oral immunization with attenuated Salmonella enterica serovar Typhimurium encoding Cryptosporidium parvum Cp23 and Cp40 antigens induces a specific immune response in mice.
Attenuated Salmonella enterica serovar Typhimurium vaccine strain SL3261 was used as an antigen delivery system for the oral immunization of mice against two Cryptosporidium parvum antigens, Cp23 and Cp40. Each antigen was subcloned into the pTECH1 vector system, which allows them to be expressed as fusion proteins with highly immunogenic fragment C of tetanus toxin under the control of the anaerobically inducible nirB promoter. The recombinant vector was introduced into Salmonella Typhimurium vaccine strain SL3261, and the stable soluble expression of the chimeric protein was evaluated and confirmed by Western blotting with polyclonal C. parvum antisera. Mice were inoculated orally with a single dose of SL3261/pTECH-Cp23 or Cp40, respectively, and plasmid stability was demonstrated both in vitro and in vivo. Specific serum immunoglobulin G (IgG) antibodies against the Cp23 or Cp40 antigen were detected by enzyme-linked immunosorbent assay 35 days after immunization. Also, serum IgA and mucosal (feces) IgA antibodies were detected in 30% of the mice immunized with Cp23. In addition, prime-boosting with Cp23 and Cp40 DNA vaccine vectors followed by Salmonella immunization significantly increased antibody responses to both antigens. Our data show that a single oral inoculation with recombinant S. Typhimurium SL3261 can induce specific antibody responses to the Cp23 or Cp40 antigen from C. parvum in mice, suggesting that recombinant Salmonella is a feasible delivery system for a vaccine against C. parvum infection.
Benitez
Alvaro J
AJ
Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30033, USA.
McNair
Nina
N
Mead
Jan R
JR
D000284:Administration, Oral; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D016785:Cryptosporidium parvum / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000737:chemistry; D005260:Female; D005822:Genetic Vectors; D007070:Immunoglobulin A / Q000032:analysis / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D012486:Salmonella typhimurium / Q000235:genetics*; D013744:Tetanus Toxin / Q000235:genetics / Q000276:immunology
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D010446:Peptide Fragments; D016052:Protozoan Vaccines; D011993:Recombinant Fusion Proteins; D013744:Tetanus Toxin; C040635:tetanus toxin fragment C