Localization of a 56-kDa antigen that is present in multiple developmental stages of Neospora caninum.
The purpose of the present study was to characterize the intracellular distribution of a native Neospora caninum 56-kDa protein that is recognized by sera from N. caninum-infected dairy cattle. The complementary DNA coding for this protein was expressed in Escherichia coli as a polyHis fusion protein to which antiserum was prepared and used to localize the antigen in N. caninum tachyzoites and bradyzoites. By sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting, antirecombinant Nc56 serum recognized a major 56-kDa protein and 2 minor (43 and 39 kDa) proteins of N. caninum tachyzoites. Antiserum to recombinant 56-kDa protein showed this antigen to be present in both N. caninum tachyzoites and bradyzoites/cysts as detected by immunofluorescence staining. Immunoelectron microscopy revealed the 56-kDa antigen to be present in the apical end of both tachyzoites and bradyzoites and possibly extracellularly secreted by tachyzoites.
Animal Parasitic Diseases Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705, USA. mjenkins@anri.barc.usda.gov
Mark
M
Jenkins
Rodrigo
R
Soares
Charles
C
Murphy
Andrew
A
Hemphill
Ryan
R
O'Handley
J P
JP
Dubey
D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D015152:Blotting, Northern / Q000662:veterinary; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis; D003048:Coccidiosis / Q000175:diagnosis / Q000662:veterinary; D018076:DNA, Complementary / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D005260:Female; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D007106:Immune Sera / Q000276:immunology; D015151:Immunoblotting / Q000662:veterinary; D008018:Life Cycle Stages / Q000276:immunology; D051379:Mice; D016253:Microscopy, Immunoelectron / Q000662:veterinary; D018688:Neospora / Q000276:immunology* / Q000648:ultrastructure; D015800:Protozoan Proteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D012333:RNA, Messenger / Q000737:chemistry; D011817:Rabbits
D000953:Antigens, Protozoan; D018076:DNA, Complementary; D007106:Immune Sera; D015800:Protozoan Proteins; D012333:RNA, Messenger