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United States Department of Agriculture

Agricultural Research Service


item Baszler, Timothy
item Knowles, Donald
item Dubey, Jitender
item Gay, John
item Mathison, Bruce
item Mcelwain, Terry

Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Neospora caninum is a recently described protozoan (single-celled) parasite of livestock and companion animals. It is a major cause of abortion in diary cattle in the U.S. Its life cycle and sources of infection are unknown. Diagnosis of protozoal abortion in cattle is difficult because N. caninum closely resembles related protozoans that cause abortion in livestock. Scientists at the Beltsville Agricultural Research Center and the Washington State University describe a monoclonal antibody (4A4-2) specific for N. caninum. The results will be useful for diagnosing neosporosis abortion in cattle

Technical Abstract: Neospora caninum, a protozoan parasite closely related to Toxoplasma gondii, causes abortion and congenital infection in cattle. To investigate specific methods of antemortem diagnosis, the antibody response of infected cows was evaluated by immunoblot assay and by competitive inhibition ELISA using a monoclonal antibody, MAb 4A4-2, against N. caninum tachyzoites. MAb 4A4-2 bound diffusely to the exterior surface of N. caninum tachyzoites and recognized a single 65 kDa band in immunoblots. MAb 4A4-2 was unreactive to antigen of two closely related apicomplexan protozoa, Toxoplasma gondii or Sarcocystis cruzi. Binding of MAb 4A4-2 was inhibited by mild periodate treatment of N. caninum antigen but was not inhibited by treatment of antigen with proteinase K. Immunoblot analysis of N. caninum tachyzoite antigens with sera from cows with confirmed Neospora-induced abortion revealed at minimum 14 major antigens ranging from 11-175 kDa. Although the recognized antigens varied from cow to cow, antigens of 116, 65, and 25 kDa were detected in all cows with confirmed Neospora abortion. The binding of MAb 4A4-2 to N. caninum tachyzoite antigen was consistently inhibited by sera from Neospora-infected cows in a competitive inhibition ELISA format and was not inhibited by sera from Neospora antibody negative cows

Last Modified: 10/18/2017
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