Volume 65 (2015) Issue: 2015 No#2

Cellular immune response to interferon-τ in peripheral blood mononuclear cells of japanese black cattle with bovine leukemia virus infection

Author(s): Sei-Ichi Kakinuma, Tomohiro Izawa, Kei-Ichi Matsuda, Satoru Kon-Nai, Yosuke Maeda, Hiromichi Ohtsuka

Keywords:bovine leukemia virus, cellular immune factor, interferon-τ, Japanese Black

IFN-τ is a type I interferon, and it is known to be non-virus inducible in ruminants. IFN-τ reduced syncytium formation by PBMC obtained from BLV infected cattle in vitro. In order to clarify the effects of IFN-τ on cellular immune function in Japanese Black (JB) cattle with bovine leukemia virus (BLV) infection, immune related factors of peripheral blood mononuclear cells (PBMC) were analyzed using IFN-τ as a stimulator. Thirty-two JB cattle were used in this investigation, and these cattle were divided into three groups: cattle with enzootic bovine leucosis (EBL) (EBL Group, N=7), clinically healthy cattle with BLV infection (Carrier Group, N=13), and clinically healthy cattle without BLV infection (non-Carrier Group, N=12). A number of mRNA expressions of interleukin-12 and interferon (IFN)-γ as immune cell activating cytokines, perforin and granulysin as cytotoxic factors, and myxovirus resistance protein (MX)-1 and MX-2 as anti-virus factors of PBMC were analyzed after culturing cells with phytohemagglutinin (PHA) or IFN-τ. The basal mRNA levels of perforin and granulysin in the Carrier Group were significantly higher than those in the non-Carrier Group. Also, significantly higher basal mRNA levels of MX-1 and MX-2 in the EBL Group were detected compared with the non-Carrier Group. The mRNA expressions of perforin and granulysin in PBMC stimulated with PHA were higher in the Carrier Group than those in the non-Carrier Group. There were significantly higher mRNA levels of MX-1 and MX-2 in PBMC stimulated with IFN-τ in the EBL Group compared with those in the non-Carrier Group. These results suggest an enhanced sensitivity of anti-virus reaction in PBMC by IFN-τ treatment in JB cattle with EBL.