Author
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Elliott, Margaret |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 2/16/2007 Publication Date: 5/22/2006 Citation: Elliott, M.K. 2006. Bovine Immune Response to Papillomatous Digital Dermatitis (PDD)-Associated Spirochetes are Skewed in Isolate Reactivity and Subclass Elicitation [abstract]. American Society for Microbiology 107th General Meeting. p. 233. Interpretive Summary: Technical Abstract: Background: Papillomatous digital dermatitis (PDD), also known as hairy heel wart, is a growing cause of lameness of cows in the U.S. dairy industry. Previous work using lesion material from a dairy farm in Iowa resulted in the isolation of four different Treponema phagedenis-like spirochetes (1A, 3A, 4A and 5B). Sera used to determine antigencity of the isolates was not drawn from the same cows the lesion material was collected from. Specific differences in antigenicity between the isolates could not be fully determined. The purpose of this study was to evaluate the serological response to these isolates from cattle known to be infected with them and to determine if differences in antigenicity existed. Methods: Jersey and Holstein bull calves were inoculated with a mixture of all 4 isolates (1:1:1:1), or 3A alone, at 10**11 spirochetes per inoculum subcutaneously in the upper neck region or intradermaly in the heel bulb of one foot. Blood was collected and sera analyzed by ELISA at 14 days post injection using whole formalin-killed spirochetes. Western blots were used to determine if antigenic proteins differed between the isolates. Results: The antibody response elicited in the cattle receiving the mixed inoculum was directed predominantly at 5B and 1A. IgG2 was the predominant subclass produced to all of the isolates. Very little IgG1, and no IgM were detected. Western blot analysis revealed an antigenic band at 35kDa in membrane preparations and 2 antigenic bands in whole cell lysates at 30 and 35kDa for all four isolates. An antigenic band at 50kDa was unique for isolate 1A. Conclusions: These results show that spirochetes isolated from a dairy in Iowa elicit a similar serological response as seen with isolates from California with IgG2 predominating. Membrane and non-membrane components are antigenic in these spirochetes. Interestingly, a mixed inoculum of equal numbers of spirochetes did not elicit equal amounts of antibody to each, indicating that in PDD, the serological response is likely dominated by certain strains of spirochetes in the lesion and the lack of detected antibodies may not indicate lack of presence for any given spirochete. |
