Norbert Schmeer

Poxvirus-Induced Immunostimulating Effects on Porcine Leukocytes

ABSTRACT The prophylactic application of inactivated parapox ovis viruses (Baypamun; Bayer AG, Leverkusen, Germany) has been shown to reduce efficiently the outbreak of stress-mediated diseases in different species. However, little is known about the basic mechanism behind this observed stimulatory property. We therefore tested eight inactivated poxvirus strains belonging to three different genera (Orthopoxvirus, Avipoxvirus, andParapoxvirus) for their capacity to activate cells of the porcine innate and specific immune systems in vitro. The results indicated that poxviruses failed to induce increased phagocytosis, oxidative burst, or natural killer cell activity in swine. In contrast, enhanced release of interleukin-2, alpha interferon, and gamma interferon, as well as strong proliferation, could be measured. Flow cytometric analyses and cell sorting experiments identified T-helper cells as the main target responding to inactivated poxviruses: the activated cells had a CD4high CD25+ major histocompatibility complex type II-positive phenotype and were the major source of secreted cytokines. Together, the results demonstrated that all tested poxviruses possessed immunostimulating capacity. These in vitro poxvirus-induced effects may be responsible at least in part for the in vivo immunostimulating capacity of inactivated poxviruses.

Isolation of a cytopathogenic virus from a case of porcine reproductive and respiratory syndrome (PRRS) and its characterization as parainfluenza virus type 2.

SummaryFrom a lung of a fetus of a breeding sow showing PRRS-like symptoms a viral agent could be isolated. It was characterized as an enveloped, hemag-glutinating RNA virus. Ultrastructural examination of purified virus revealed paramyxovirus-like pleomorphic virions of approx. 200 nm in diameter. The helical nucleocapsids were about 18 nm in diameter. The virus was found to be antigenically related to simian virus 5 (SV5) a prototype strain of parainfluenza virus type 2, but not to bovine respiratory syncytial virus, parainfluenza virus type 1, parainfluenza virus type 3, and Newcastle disease virus as determined by western blot analysis.

Synthesis and antibacterial in vitro activity of novel analogues of nematophin

The synthesis and in vitro antibacterial activity of new derivatives and analogues of nematophin are described. It was shown that the unsubstituted amide NH-group is essential for bioactivity. Alkyl- or arylsubstitution at the 1-position results in a distinct increase of antibacterial activity. Addition of protein (blood or serum) to the culture media reduces the inhibitory activity on bacteria.