Quantitative analysis of cytokine mRNA expression and protozoan DNA load in Theileria parva-infected cattle.
Theileria parva (T. parva) causes a highly serious bovine disease called East Coast fever (ECF), which is characterized by pyrexia, dyspnea and cachexia and is of great economic importance in African countries. We hypothesize that the clinical symptoms of ECF could be explained by a cytokine dysregulation. In this study, we investigated the relationship between T. parva DNA load and expression levels of cytokine mRNAs in leukocytes from experimentally infected calves by quantitative PCR. The p104 gene, which encodes the T. parva 104 kDa microneme-rhoptry protein, was detected in cattle blood from day 10 after T. parva-infected tick infestation, and the protozoan DNA load was increased together with severity of disease. The mRNA expressions of pro-inflammatory cytokines, such as interleukin (IL)-1beta and IL-6, were up-regulated with protozoan DNA load increasing. In addition, the level of a type-2 cytokine (IL-10) transcript was also increased during the acute phase. In contrast, the down-regulation or no detectable levels of the expression of type-1 cytokines, such as IL-2 and interferon (IFN)-gamma were observed in T. parva-infected animals. Thus, our observations indicated that high protozoan load and resulting intense inflammatory responses might be involved in the severity of clinical signs observed in T. parva-infection.
Yamada
Shinji
S
Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Konnai
Satoru
S
Imamura
Saiki
S
Simuunza
Martin
M
Chembensofu
Mwelwa
M
Chota
Amos
A
Nambota
Andrew
A
Onuma
Misao
M
Ohashi
Kazuhiko
K
D000818:Animals; D002417:Cattle; D016207:Cytokines / Q000276:immunology / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D016054:DNA, Protozoan / Q000097:blood*; D007962:Leukocytes / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D016797:Theileria parva / Q000235:genetics*; D013801:Theileriasis / Q000276:immunology* / Q000469:parasitology
D016207:Cytokines; D017931:DNA Primers; D016054:DNA, Protozoan; D012333:RNA, Messenger