Proinflammatory Cytokine Changes in Bronchoalveolar Lavage Fluid Cells Isolated from Pigs Infected Solely with Porcine Reproductive and Respiratory Syndrome Virus or Co-infected with Swine Influenza Virus.

INTRODUCTION: The study evaluated the patterns of local innate immune response in bronchoalveolar lavage fluid (BALF) cells of pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV) alone or co-infected with swine influenza virus (SIV). MATERIAL AND METHODS: The study was performed on 26 seven-week-old pigs in three groups: PRRSV-infected (n = 11), PRRSV and SIV-infected (n = 11), and control (n = 4). BALF was collected post euthanasia at 2 and 4 dpi (three piglets per inoculated group) and at 21 dpi (all remaining pigs). Expression of IFN-α, IFN-γ, IL-1ß, IL-6, IL-8, and IL-10 mRNA was quantified in BALF cells. PRRSV RNA was quantified in BALF samples using a commercial real-time RT-PCR kit. RESULTS: The three cytokines IFN-α, IFN-γ, and IL-1ß presented significant expression changes in all experimental pigs. In PRRSV-infected animals IL-8 also did, but in co-infected subjects IL-6 and IL-10 were the additional upregulated cytokines. The highest number of differentially expressed genes was observed at 4 dpi, and significant differences in cytokine gene expression did not occur between the experimental groups at any other time point. The mean PRRSV load in the BALF of PRRSV-infected pigs was higher than that of co-infected pigs at each time point, having statistical significance only at 4 dpi. CONCLUSION: The results of the study indicate that infection with PRRSV alone as well as with SIV interferes with innate and adaptive immune response in the infected host. They also showed that co-infection demonstrates additive effects on IL-6 and IL-10 mRNA expression levels.

Effects of Newly Developed Synbiotic and Commercial Probiotic Products on The Haematological Indices, Serum Cytokines, Acute Phase Proteins Concentration, and Serum Immunoglobulins Amount in Sows and Growing Pigs - A Pilot Study.

INTRODUCTION: The aim of the study was to determine the effects of supplementation of sows' and growing pigs' diets with three newly developed synbiotic and two extant commercial probiotic products on selected immune parameters under field conditions. MATERIAL AND METHODS: The study was performed on 30 sows and 48 piglets of the Danbred breed. Immune parameters such as concentration and proportion of white blood cells and their subpopulations, immunoglobulins amount in serum, and serum concentration of cytokines and acute phase proteins were recorded with the use of a haematology analyser and ELISA kits. RESULTS: No significant differences between treatment groups and controls were found with regard to the immune parameters evaluated except for serum immunoglobulin concentration, which was significantly increased by synbiotic products B and C and probiotic product D. CONCLUSION: The results of the study indicate that the synbiotic products B and C and probiotic product D are worthy of further investigation as promising candidates to improve the immune status of healthy sows and their offspring.

Kinetics of single and dual infection of pigs with swine influenza virus and Actinobacillus pleuropneumoniae.

Porcine respiratory disease complex (PRDC) is a common problem in modern pork production worldwide. Pathogens that are amongst other pathogens frequently involved in PRDC etiology are swine influenza virus (SIV) and A. pleuropneumoniae. The effect of dual infection with mentioned pathogens has not been investigated to date. The aim of the present study was to evaluate the kinetics of single and dual infection of pigs with SIV and A. pleuropneumoniae with regard to clinical course, pathogens shedding, lung lesions and early immune response. The most severe symptoms were observed in co-inoculated piglets. The AUC value for SIV shedding was lower in pigs single inoculated with SIV as compared to co-inoculated animals. In contrast, no significant differences were found between A. pleuropneumoniae shedding in single or dual inoculated pigs. Three out of 5 co-inoculated piglets euthanized at 10 dpi were positive against serotype 2 A. pleuropneumonie. All piglets inoculated with SIV developed specific HI antibodies at 10 dpi. In pigs dual inoculated the specific humoral response against SIV was observed earlier, at 7 dpi. The SIV-like lung lesions were more severe in co-inoculated pigs. In the groups inoculated with A. pleuropneumoniae (single or dual) the acute phase protein response was generally stronger than in SIV-single infected group. Co-infection with SIV and A. pleuropneumoniae potentiated the severity of lung lesions caused by SIV and enhanced virus replication in the lung and nasal SIV shedding. Enhanced SIV replication contributed to a more severe clinical course of the disease as well as earlier and higher magnitude immune response (acute phase proteins, HI antibodies) compared to single inoculated pigs.

Pig Lung Immune Cytokine Response to the Swine Influenza Virus and the Actinobacillus Pleuropneumoniae Infection.

INTRODUCTION: The aim of this study was to evaluate and compare the local innate immune response to the swine influenza virus (SIV) and Actinobacillus pleuropneumoniae (App) infection in pigs. MATERIAL AND METHODS: The study was performed on 37 seven-week-old pigs, divided into four groups: App-infected (n=11), App+SIV-infected (n=11), SIV-infected (n=11), and control (n=4). Lung samples were collected, following euthanasia, on the 2nd and 4th dpi (three piglets per inoculated group) and on the 10th dpi (remaining inoculated and control pigs). Lung concentrations of IL-1ß, IL-6, IL-8, TNF-α, IL-10, IFN-α, and IFN-γ were analysed with the use of commercial porcine cytokine ELISA kits. RESULTS: Lung concentrations of IL-1ß, IL-6, IL-8, TNF-α, IFN-α, and IFN-γ were induced in SIV-infected and App+SIV-infected pigs. In the lung tissue of App-infected pigs, only concentrations of IL-1ß, IL-6, IL-8, and IFN-γ were elevated. Additionally, in App+SIV-infected pigs, significantly greater concentrations of IL-1ß, IL-8, and IFN-α were found when compared with pigs infected with either SIV or App alone. In each tested group, the lung concentration of IL-10 remained unchanged during the entire study. CONCLUSION: The results of the study indicate that the experimental infection of pigs with SIV or App alone and co-infection with both pathogens induced a local lung inflammatory response. However, the local cytokine response was considerably higher in co-infected pigs compared to single-infected pigs.