Recognition patterns of Neospora caninum tachyzoite antigens by bovine IgG at different IFAT titres

TitleRecognition patterns of Neospora caninum tachyzoite antigens by bovine IgG at different IFAT titres
Publication TypeJournal Article
Year of Publication2004
AuthorsOkeoma, C.M., Williamson N.B., Pomroy W.E., and Stowell K.M.
JournalParasite Immunology
Pagination177 - 185
Date Published2004
ISBN Number01419838 (ISSN)
KeywordsAbortion, Veterinary, Animalia, Animals, antibody response, antigen recognition, Antigens, Antigens, Protozoan, article, Blotting, Western, Bos taurus, Bovinae, bovine immunoglobulin, cattle, Cattle Diseases, Coccidiosis, controlled study, cow, enzyme linked immunosorbent assay, female, Fluorescent Antibody Technique, Indirect, IFAT, IgG, immunofluorescence test, immunoglobulin G, intermethod comparison, Neospora, Neospora caninum, nonhuman, parasite antigen, Pregnancy, Pregnancy Complications, Parasitic, priority journal, Western blot, Western blotting

This study describes qualitative and quantitative antibody response in cows naturally infected with Neospora caninum. The study was carried out with 269 serum samples obtained from 24 cows over a period of 15 weeks. Prior to sample collection, the cows were tested with ELISA. The 269 samples were screened with IFAT and categorized into seven IFAT titre groups (< 1:80, 1:80, 1:200, 1:600, 1:1000, 1:2000, > 1:2000). The samples were finally analysed by Western blotting. Seven immunodominant antigens (∼18-, ∼25-, ∼33-, ∼35-36-, ∼45-46-, ∼47-, ∼60-62 kDa) and five minor antigens (∼25, ∼51, ∼64, ∼77, ∼116 kDa) were recognized by cow sera. The recognition of ∼46 kDa antigen by cow sera was common to samples with IFAT titre 1:80 and above. Another common antigen was the ∼18 kDa antigen, which was recognized by samples with IFAT titre 1:200 and above. The most remarkable observation was the presence of the 45-46 kDa, the 77 kDa, and absence of the 18 kDa antigenic bands in samples with IFAT titre 1:80. This observation was consistent even in the face of fluctuating antibody titre where serum antibody titres from an animal exceeded then failed to reach 1:80. Antibody fluctuation was observed across all cows (pregnant and aborted) with no discernible fluctuation pattern. However, the fluctuation in antibody titre observed appeared to be most remarkable in initially ELISA-negative pregnant cows, and to a lesser extent in ELISA-positive pregnant cows, and ELISA-positive aborted cows. Although there was fluctuation in antibody titre, the banding patterns of N. caninum tachyzoite antigens by cows within the same IFAT titre group remained similar.

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