A.D. Irvin

Bio: A.D. Irvin is an academic researcher. The author has contributed to research in topics: Theileria & Immunopathology. The author has an hindex of 1, co-authored 1 publications receiving 103 citations.

Transformation of Leukocytes by Theileria parva and T. annulata

Abstract: Theileria parva and T. annulata provide intriguing models for the study of parasite-host interactions. Both parasites possess the unique property of being able to transform the cells they infect; T. parva transforms T and B cells, whereas T. annulata affects B cells and monocytes/macrophages. Parasitized cells do not require antigenic stimulation or exogenous growth factors and acquire the ability to proliferate continuously. In vivo, parasitized cells undergo clonal expansion and infiltrate both lymphoid and non-lymphoid tissues of the infected host. Theileria-induced transformation is entirely reversible and is accompanied by the expression of a wide range of different lymphokines and cytokines, some of which may contribute to proliferation or may enhance spread and survival of the parasitized cell in the host. The presence of the parasite in the host-cell cytoplasm modulates the state of activation of a number of signal transduction pathways. This, in turn, leads to the activation of transcription factors, including nuclear factor-kappa B, which appear to be essential for the survival of Theileria-transformed T cells.

An enzyme-linked immunosorbent assay for detection of Theileria parva antibodies in cattle using a recombinant polymorphic immunodominant molecule

Abstract: Field and experimental bovine infection sera were used in immunoblots of sporozoite and schizont lysates of Theileria parva to identify candidate diagnostic antigens. Four parasite antigens of Mr 67,000 (p67), 85,000 (the polymorphic immunodominant molecule, PIM), 104,000 (p104), and 150,000 (p150) were selected for a more detailed analysis. The p67 and p104 antigens were present only in the sporozoite lysates, whereas PIM and p150 were found in both sporozoite and schizont lysates. The four antigens were expressed as recombinant fusion proteins and were compared with each other in an enzyme-linked immunosorbent assay (ELISA) and in the whole-schizont-based indirect fluorescent antibody test (IFAT) in terms of their ability to detect antibodies in sera of experimentally infected cattle. The PIM-based ELISA provided a higher degree of sensitivity and specificity than did the ELISA using the other three recombinant antigens or the IFAT. Further evaluation of the PIM-ELISA using experimental sera derived from cattle infected with different hemoparasites and field sera from endemic and nonendemic T. parva areas showed that the assay had a sensitivity of > 99% and a specificity of between 94% and 98%.

Ribosomal small-subunit RNA gene-sequence analysis of Theileria lestoquardi and a Theileria species highly pathogenic for small ruminants in China.

Abstract: A fatal disease of sheep and goats in the northwestern part of China has been reported to be due to Theileria lestoquardi (syn. T. hirci). However, some characteristics of the causative agent are not in accordance with attributes ascribed to this parasite. We therefore determined the nucleotide sequence of the small-subunit ribosomal RNA (srRNA) gene of T. lestoquardi and the parasite identified in China and compared it with that of other Theileria and Babesia species. In the inferred phylogenetic tree the srRNA sequence of the Chinese parasite was found to be most closely related to T. buffeli and clearly divergent from T. lestoquardi, suggesting that it is an as yet unrecognized Theileria species. Extensive structural similarities were observed between the srRNA sequences of T. lestoquardi and T. annulata, revealing a close phylogenetic relationship between these two Theileria species. On the basis of the srRNA nucleotide sequence, polymerase chain reaction (PCR) primers were designed that specifically amplified genomic DNA of the Chinese Theileria species. These primers may be valuable tools in future epidemiology studies.