The alcelaphine herpesvirus-1 ORF 57 encodes a nuclear shuttling protein

Alcelaphine herpesvirus-1 (AlHV-1) is a γ₂ rhadinovirus associated with Malignant Catarrhal Fever (MCF) in cattle. ORF 57 is well conserved among gammaherpesviruses and it has been shown that the ORF 57 gene products of Herpesvirus Saimiri (HVS), Kaposi’s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) play an important role in regulating viral gene expression. The AlHV-1 ORF 57 gene product has not been characterized. In the accompanying paper we have demonstrated that AlHV-1 ORF 57 encodes an immediate early protein that acts as a regulator of gene expression. The ORF 57 gene product has an up-regulatory effect only on another immediate early gene product encoded by ORF 50. Here we show that the ORF 57 gene product is a nuclear protein. When ORF 57 was fused to the gene encoding Enhanced Green Fluorescent Protein (EGFP), the fusion protein exhibited a punctate nuclear distribution that co-localized with the nucleolar phosphoprotein C23. The nuclear localisation signal of ORF 57 gene product was located at the N-terminus. The ORF 57 gene product travels from nucleus to the cytoplasm, where it accumulates during Actinomycin D treatment. The domain involved in nuclear shuttling was also localised at the N-terminal region of the protein. Thus in common with homologues in other herpesviruses the AlHV-1 ORF 57 gene product is a nuclear cytoplasmic shuttling protein which may play a role in export of viral mRNAs from the nucleus of infected cells.     

Jaagsiekte sheep retrovirus is present at high concentration in lung fluid produced by ovine pulmonary adenocarcinoma-affected sheep and can survive for several weeks at ambient temperatures

Jaagsiekte sheep retrovirus (JSRV) causes a fatal lung cancer of sheep known as ovine pulmonary adenocarcinoma (OPA). OPA is a significant disease in many sheep-rearing countries and there is no effective method of control. A unique feature of OPA is the overproduction of fluid in the lung of affected animals. This lung fluid contains JSRV and provides a means of transmission through the inhalation of virus. In this study we demonstrated that lung fluid from different OPA cases contained between 10⁷ and 10¹⁰ copies of JSRV RNA per ml. Examination of JSRV RNA survival under conditions that mimic natural conditions suggested that intact JSRV virions may persist for several weeks in the environment. These are the first quantitative data on JSRV in lung fluid and provide valuable information for implementing appropriate biosecurity measures to control the spread of JSRV in the field.     

Characterisation of antibodies to bovine Toll-like receptor (TLR)-2 and cross-reactivity with ovine TLR2

Host recognition of conserved pathogen-associated molecular patterns (PAMPs) and their interactions with pattern-recognition receptors, including the Toll-like receptors (TLR) is essential for innate immune response induction. The TLR1 family (TLR1, 2, 6 and 10) is involved in the recognition of gram-positive and gram-negative bacteria and heterodimers of TLR1 or TLR6 with TLR2 are crucial for the identification of several PAMPs. Studies on cell surface expression of TLR in ruminants are hampered by the lack of specific antibodies and no convincingly cross-reactive anti-human antibodies have been described so far. We describe herein four antibodies which recognise bovine TLR2. Differences in TLR2 expression were evident on bovine antigen presenting cells with high level expression on peripheral blood monocytes and monocyte-derived macrophages. Lower levels of expression were evident on dendritic cell populations derived in vitro and ex vivo, and on alveolar macrophages. One of the antibodies recognised TLR2 expression on ovine peripheral blood monocytes. The identification of antibodies specific for bovine and ovine TLR2 will facilitate studies of the role of this important PRR in the initiation of immune responses to important pathogens.