Serum and colostrum antibody responses induced by jet-injection of sheep with DNA encoding a Cryptosporidium parvum antigen.
In an effort to generate high titer colostrum for immunotherapy of cryptosporidiosis, a study was conducted to test the efficacy of immunizing sheep with recombinant plasmid DNA (pCMV-CP15/60) encoding epitopes of 15 and 60 kDa surface antigens of Cryptosporidium parvum sporozoites. The plasmid DNA was used to immunize preparturient ewes at three dose levels by jet-injection into either hind limb muscle (IM) or mammary tissue (IMAM). Regardless of route of injection, a dose-dependent anti-CP15/60 immunoglobulin response was observed in sera and colostrum from sheep immunized with pCMV-CP15/60 plasmid DNA. High titer antibody responses were observed in one of three animals per group receiving an IM injection of 100 or 1000 micrograms pCMV-CP15/60. IMAM immunization with 100 or 1000 micrograms pCMV-CP15/60 plasmid DNA elicited higher titer colostrum responses and more consistent serum responses compared to IM injections. A negligible serum and colostrum anti-CP15/60 response was observed in ewes injected IM with 10 micrograms pCMV-CP15/60 or 1000 micrograms control plasmid DNA. Immunoblotting of native C. parvum sporozoite/oocyst protein with hyperimmune serum and colostrum corroborated the increased titers against CP15/60 antigen. Serum and colostrum antibodies from pCMV-CP15/60-immunized sheep were eluted from native CP15 protein and bound a surface antigen of C. parvum sporozoites as indicated by indirect immunofluorescence staining.
Jenkins
M
M
Parasite Immunobiology Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705, USA.
Kerr
D
D
Fayer
R
R
Wall
R
R
D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis* / Q000097:blood*; D000953:Antigens, Protozoan / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology*; D003126:Colostrum / Q000276:immunology*; D003457:Cryptosporidiosis / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary; D016785:Cryptosporidium parvum / Q000276:immunology*; D016054:DNA, Protozoan / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D006614:Hindlimb; D007277:Injections, Jet; D008321:Mammary Glands, Animal; D016052:Protozoan Vaccines / Q000276:immunology; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000517:prevention & control; D014614:Vaccines, Synthetic / Q000276:immunology
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D016052:Protozoan Vaccines; D014614:Vaccines, Synthetic