Age-dependent resistance to Porcine reproductive and respiratory syndrome virus replication in swine.

Background: Porcine reproductive and respiratory syndrome virus (PRRSV) causes a prolonged, economically devastating infection in pigs, and immune resistance to infection appears variable. Since the porcine adaptive immune system is not fully competent at birth, we hypothesized that age influences the dynamics of PRRSV infection. Thus, young piglets, growing 16-20-week-old finisher pigs, and mature third parity sows were infected with virulent or attenuated PRRSV, and the dynamics of viral infection, disease, and immune response were monitored over time.

IL-13 replaces IL-4 in development of monocyte derived dendritic cells (MoDC) of swine.

Dendritic cells (DCs) are a critical aspect of innate immune responses in addition to initiating adaptive immunity. In vitro generation of monocyte derived dendritic cells (MoDC) by culturing cells in IL-4 and granulocyte/macrophage colony stimulating factor (GM-CSF) has been reported for multiple species including swine. However, IL-4 is not a prominent cytokine detected in the periphery of common breeds of swine such as Yorkshire pigs.

A bilingual "neighborhood club": intervening with children exposed to urban violence.

Mental health practitioners have offered relatively little in response to the pervasive community violence faced by many children living in impoverished neighborhoods. The "neighborhood club" is a school-based, short-term, support group designed to assist children with the psychological impact of exposure to community violence. Ten "neighborhood clubs" were conducted in two public elementary schools in Detroit, Michigan.

Immunopotentiation of a foot-and-mouth disease virus subunit vaccine by interferon alpha.

The adjuvant effect of porcine interferon alpha (pIFN-alpha) was examined in swine vaccinated with a replication-defective adenovirus containing foot-and-mouth disease virus (FMDV) A24 capsid and 3C proteinase coding regions (Ad5-A24). Groups of swine were inoculated with either high or low doses of Ad5-A24 in the presence or absence of Ad5-pIFNalpha or with a control Ad5 and challenged by intradermal inoculation in the heel bulb with FMDV at 42 days post-vaccination. After challenge all control animals developed viremia and lesions.

Constitutive expression of alpha interferon by skin dendritic cells confers resistance to infection by foot-and-mouth disease virus.

The role of dendritic cells (DC) in the initiation of immune responses against foot-and-mouth disease virus (FMDV) is poorly understood. We analyzed the innate response of freshly isolated swine skin DC to the virus and show a rapid induction of beta interferon (IFN-beta) mRNA but not IFN-alpha mRNA. However, these DC secreted both IFN-alpha and IFN-beta proteins in response to live virus but not killed virus.

Induction of lymphopenia and inhibition of T cell function during acute infection of swine with foot and mouth disease virus (FMDV).

Foot and mouth disease virus (FMDV) is a picornavirus that causes an acute vesicular disease of cloven-hoofed animals. This virus continues to be a threat to livestock worldwide with outbreaks causing severe economic losses. The present study shows an analysis of immune system phenotype and function during the acute phase of FMDV infection in swine.

Functional properties of the predicted helicase of porcine reproductive and respiratory syndrome virus.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a member of the positive-strand RNA virus family Arteriviridae. Although considerable research has focused on this important pathogen, little is known about the function of most PRRSV proteins. To examine characteristics of putative nonstructural proteins (nsp) encoded in ORF1b, which have been identified by nucleotide similarity to domains of equine arteritis virus, defined genomic regions were cloned and expressed in the pRSET expression system.

Characterization and functional analysis of skin-derived dendritic cells from swine without a requirement for in vitro propagation.

A low-density cell population was isolated from skin explants of pigs and characterized as a highly enriched dendritic cell (DC) population based on phenotypical and functional properties. The skin-derived DCs were identified by their characteristic ultrastructural properties as well as by consistent co-expression of the CD1 and SWC3a antigens that clearly differentiate them from other porcine leukocytes. These cells exhibit higher expression of porcine MHC class II (SLAII) and CD80/86 antigens as compared to macrophage/monocyte cells.