Imbalance of tumor necrosis factor receptors during progression in bovine leukemia virus infection.
Previously, we found an up-regulation of tumor necrosis factor alpha (TNF)-alpha and an imbalance of TNF receptors in sheep experimentally infected with bovine leukemia virus (BLV). In order to investigate the different TNF-alpha-induced responses, in this study we examined the TNF-alpha-induced proliferative response and the expression levels of two distinct TNF receptors on peripheral blood mononuclear cells (PBMC) derived from BLV-uninfected cattle and BLV-infected cattle that were aleukemic (AL) or had persistent lymphocytosis (PL). The proliferative response of PBMC isolated from those cattle with PL in the presence of recombinant bovine TNF-alpha (rTNF-alpha) was significantly higher than those from AL cattle and uninfected cattle and the cells from PL cattle expressed significantly higher mRNA levels of TNF receptor type II (TNF-RII) than those from AL and BLV-uninfected cattle. No difference was found in TNF-RI mRNA levels. Most cells expressing TNF-RII in PL cattle were CD5+ or sIgM+ cells and these cells showed resistance to TNF-alpha-induced apoptosis. Additionally, there were significant positive correlations between the changes in provirus load and TNF-RII mRNA levels, and TNF-alpha-induced proliferation and TNF-RII mRNA levels. These data suggest that imbalance in the expression of TNF receptors could at least in part contribute to the progression of lymphocytosis in BLV infection.
Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan. konnai@vetmed.hokudai.ac.jp
Satoru
S
Konnai
Tatsufumi
T
Usui
Manabu
M
Ikeda
Junko
J
Kohara
Toh-Ichi
T
Hirata
Kosuke
K
Okada
Kazuhiko
K
Ohashi
Misao
M
Onuma
D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D002417:Cattle; D018450:Disease Progression; D016583:Enzootic Bovine Leukosis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D001909:Leukemia Virus, Bovine; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D015703:Antigens, CD; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha