Phylogenetic characterisation of the G(L) sequences of equine arteritis virus isolated from semen of asymptomatic stallions and fatal cases of equine viral arteritis in Denmark.

The study describes for the first time the phylogenetic relationship between equine arteritis virus (EAV) isolated from asymptomatic virus-shedding stallions and fatal cases of equine viral arteritis (EVA) in an European country. EAV was isolated from three dead foals and an aborted foetus during three different outbreaks of EVA. From these fatalities, the complete open reading frame 5, encoding the EAV G(L) protein, was amplified by reverse transcription-polymerase chain reaction and subjected to nucleotide sequence analysis. Furthermore, DNA sequences were obtained from virus isolated from semen samples of seven virus-shedding, but clinically healthy, Danish stallions. DNA sequence alignment revealed an overall divergence of 0-14 and 0-10% at the nucleotide and amino acid levels, respectively. Phylogenetic analysis including 24 previously published sequences revealed that European as well as North American "types" of EAV were present in the semen of asymptomatic carrier stallions and in fatal cases of EVA. Our results reveal that the presence of EAV-shedding stallions in Denmark represents a potential source of severe EVA.

Reduction of serum interferon (IFN)-gamma concentration and lupus development in NZBxNZWF(1)mice by lactic dehydrogenase virus infection.

The complexity of cytokine regulation and the imbalance of helper T (Th)1 and Th2 subsets in systemic lupus erythematosus (SLE) animal models and human SLE are well recognized. In this study in NZBxNZWF(1)mice, the effects of lactic dehydrogenase virus (LDV) infection on the production of interferon (IFN)-gamma in the serum and the development of autoimmune disease were examined. The progress of the disease (the development of glomerulonephritis, formation of glomerular IgG and C3 deposits, increase in the blood urea nitrogen values, and mortality) was parallel with an increase in serum IFN-gamma in uninfected NZBxNZWF(1)mice. These changes were inhibited in LDV-infected NZBxNZWF(1)mice. Our findings suggest that increase in serum IFN-gamma may be associated with the active disease in NZBxNZWF(1)mice.

Suppression of development of glomerulonephritis in NZB x NZWF1 mice by persistent infection with lactic dehydrogenase virus: relations between intercellular adhesion molecule-1 expression on endothelial cells and leucocyte accumulation in glomeruli.

The development of glomerulonephritis (GN) in autoimmune NZB x NZWF1 mice was suppressed by persistent lactic dehydrogenase virus (LDV) infection. In this study the expression of intercellular adhesion molecule-1 (ICAM-1) on endothelial cells in glomeruli was examined during the development of GN. ICAM-1 expression on endothelial cells preceded the accumulation of leucocytes within glomeruli. The uninfected mice exhibited an age-related and profound increase in ICAM-1 expression associated with the development of a GN as evidenced by deposits of IgG and C3. Uninfected mice also showed increased accumulation of leucocytes, such as polymorphonuclear leucocytes (PMNs), macrophages, T and CD4+ cells, which express the lymphocyte function-associated antigen-1 (LFA-1) within glomeruli during the development of GN. These changes were strongly suppressed by LDV infection. Our findings suggest that the expression of ICAM-1 in glomerular endothelial cells may, at least in part, contribute to the development of GN. Suppressed expression of ICAM-1 in LDV-infected mice may be responsible for the suppression of GN seen in these animals. Thus there may be a pathogenetic role for ICAM-1 expression and for intraglomerular accumulation of leucocytes, especially PMNs, which express LFA-1 in the development of GN.