Interleukin-17 producing cells in swine induced by microbiota during the early postnatal period - a brief research report.

Interleukin-17A (IL-17) is a pro-inflammatory cytokine involved in the immune response to many pathogens playing also a role in certain chronic and autoimmune diseases. The presented study focused on the early postnatal development of IL-17 producing cells in swine. In agreement with previous studies, αß T-helper (CD3+CD4+) and γδ T (CD3+TCRγδ+) cells were found to be the major producers of IL-17. In newborn conventional piglets, αß T-helper cells positive for IL-17 were almost undetectable, but their frequency increased markedly with age in all issues examined, i.e., blood, spleen, and mesenteric lymph nodes (MLN). Additional analyses of CD8 and CD27 expression showed that the main αß T-helper producers of IL-17 has CD8+CD27- phenotype in all tissues. IL-17 positive CD8+CD27+ αß T-helper subpopulation was found only in blood and spleen. The production of IL17 in CD8-CD27+ αß T-helper cells was always minor. In contrast, γδ T cells positive for IL-17 did not show a similar age-dependent increase in blood and spleen, whereas they increased in MLN. Because of the age-dependent increase in conventional animals, we included a comparison with germ-free piglets to show that the increase in IL-17 positive cells was clearly depended on the presence of the microbiota as the production in germ-free animals was negligible without any age-dependent increase.

Effects of oil-based adjuvants on the immune response of pigs after dermal administration of antigen and evaluation of the immunization level after a subsequent Actinobacillus pleuropneumoniae challenge in pigs.

Route of vaccine delivery can greatly impact the immunogenicity, efficacy and safety of the vaccine. Four groups of piglets were immunised transdermally (t.d.), intradermally (i.d.) or intramuscularly (i.m.) with the same doses of antigen in combination with a water-in-oil-in-water emulsion adjuvant Montanide™ ISA 201 VG or with a microemulsion adjuvant Montanide™ IMS 1313 VG N ST (Seppic, France). The last group was left without vaccination as a control group. All animals were subsequently exposed to the infection induced by Actinobacillus pleuropneumoniae (App). The immune response was evaluated with respect to the intensity of systemic and mucosal antibody formation, their isotype characterisation and rate of cell-mediated immunity. These findings were compared with the intensity of adverse local reactions and level of protection in experimental challenge. Monitoring of the local reaction at the injection site after each administration showed that microemulsion adjuvant IMS 1313 was less reactogenic than the water-in-oil-in-water emulsion ISA 201. In terms of efficacy, both dermal administrations were less immunogenic than the i.m route. The i.m. injection induced higher anti-App9 IgG and IgM titres. Nevertheless, IgG1 and IgG2 isotypes analysis revealed a close immunological profile between i.m. and i.d. routes. The concentration of IFN-γ from peripheral blood after in vitro restimulation with the specific antigen was only increased in the i.m. group at the day of challenge (D35) and two weeks after (D49). Interestingly, the smallest gross pulmonary lesions were observed in the i.d. vaccinated group (3.4%) compared to the control group (39.4%) and to groups with other routes of administration. Taken together, these results suggest that i.d. administration of vaccines is a promising approach. Even the i.d. vaccine was more reactogenic and slightly less immunogenic than the i.m. vaccine, its protection effectiveness seemed to be superior.

Effects of IFNγ and IL4 rich microenvironment on porcine monocyte-derived dendritic cell activation in vitro.

Dendritic cells (DCs) represent a heterogeneous group of major antigen-presenting cells, responding to different stimuli in their microenvironment. They are able to activate naïve T-cells and drive their polarization towards effector types. However, the effect of different Th-polarizing cytokine microenvironment on porcine DCs remains poorly described. Therefore, the effect of IFNγ or IL4 rich microenvironment on porcine monocyte-derived dendritic cells and their activation, antigen recognition and cytokine secretion towards T-cell polarization were studied in vitro. IFNγ-rich microenvironment induced a higher proinflammatory response and release of Th1/Th17-polarizing cytokines (IL1ß, IL12p35, IL23p19), while anti-inflammatory properties (IL10, TGFß) was not affected by a cytokine microenvironment. From the achieved results, we propose that different cytokine microenvironment has the potential to modulate dendritic cells and their ability to activate T-cells.

The impact of parturition induction with cloprostenol on immunological parameters in the sow colostrum.

BACKGROUND: Farrowing induction with prostaglandin F2 analogue cloprostenol is commonly used on commercial farms to manage the timing of farrowing. When labour induction is applied, the questions arise about possible side effects of such a hormonal intervention on physiological processes connected with labour and lactation, including colostral immunity. RESULTS: In this study, immune cells composition, lysozyme concentration, complement bacteriolytic activity and proinflamatory (GM-CSF2, IL-1ß, IL-6, a TNFα) and anti-inflammatory (IL-4, IL-10, TGFß1 a TGFß2) cytokines were measured in colostrum samples from sows farrowing naturally (NP) and from sows with farrowing induced using cloprostenol administration on day 113 of gestation (IP). A significantly higher proportion of lymphocytes was found in colostrum of induced sows compared to colostrum of non-induced sows. No significant differences between NP and IP were found in complement activity, in the proportions of granulocytes, macrophages and lymphocyte subpopulations. Lower lysozyme concentration and higher IL-1ß, IL-6, TGFß1 and TNFα concentrations were found in IP sow colostrum compared to colostrum from NP sows. CONCLUSIONS: An increased proportion of colostral lymphocytes can positively influence the cellular immunity transmission from sow to her offspring. On the other hand, a lower lysozyme concentration can adversely affect newborn's intestinal immunity, as well as changes in cytokine concentrations can have an adverse effect on newborn piglet intestinal epithelium development and its defence function.

Maternal Exposure Results in Long-Term Deoxynivalenol Persistence in Piglets' Plasma and Modulates the Immune System.

Deoxynivalenol (DON)-contaminated feed represents a serious problem for pigs due to their high sensitivity to its toxicological effects. The aim of the present study was to evaluate the impact of intrauterine DON exposure on the immune system of piglets. Pure DON was intravenously administered to sows at the end of gestation (during the last 2-3 days of gestation, one dose of 300 µg per day). The plasma concentration of DON was analyzed using liquid chromatography combined with high-resolution Orbitrap-based mass spectrometry (LC-MS/MS (HR)) and selected immune parameters were monitored six times in piglets from birth to 18 weeks. DON was found in the plasma of 90% of newborn piglets at a mean concentration of 6.28 ng/mL and subsequently, at one, three, and seven weeks after birth with decreasing concentrations. Trace amounts were still present in the plasma 14 weeks after birth. Flow cytometry revealed a significant impact of DON on T lymphocyte subpopulations during the early postnatal period. Lower percentages of regulatory T cells, T helper lymphocytes, and their double positive CD4+CD8+ subset were followed by increased percentages of cytotoxic T lymphocytes and γδ T cells. The capacity to produce pro-inflammatory cytokines was also significantly lower after intrauterine DON exposure. In conclusion, this study revealed a long-term persistence of DON in the plasma of the piglets as a consequence of short-term intrauterine exposure, leading to altered immune parameters.

The effect of polyclonal activators on rabbit B cell antibody production.

Stimulation with polyclonal activators is a tool to increase antibody secretion in B cells. The aim of the present study was to select the most effective common commercially available polyclonal activators of rabbit B cells. Specifically, type B oligodeoxynucleotides with unmethylated deoxycytidyl-deoxyguanosine dinucleotides (CpG-ODN), recombinant rabbit interleukin-2 (rrIL-2), lipopolysaccharide (LPS), pokeweed mitogen (PWM) and Resiquimod (R848) were tested on B cells isolated from blood and spleen by fluorescence-activated cell sorting. Based on the obtained data, stimulation with CpG-ODN induced the highest antigen-specific antibody levels detected by ELISA in supernatants when a single activator was used. In contrast, LPS, PWM and R848 showed a weak or no stimulatory effect. Stimulation with a mix of activators was more effective than CpG-ODN alone, which indicates a synergistic effect in the stimulation of antibody production.

Minimal Concentrations of Deoxynivalenol Reduce Cytokine Production in Individual Lymphocyte Populations in Pigs.

Deoxynivalenol (DON) is a mycotoxin frequently found in cereals, and pigs are one of the most sensitive farm species to DON. The aim of this study was to determine the effects of DON in very low doses on peripheral blood mononuclear cells (PBMC) and on particular lymphocyte subpopulations. The cells were exposed to 1, 10 and 100 ng/mL of DON and lymphocyte viability, proliferation, and cytokine (Interleukin (IL)-1ß, IL-2, IL-8, IL-17, Interferon (IFN) γ and tumor necrosis factor (TNF) α production were studied. Cells exposed to DON for 5 days in concentrations of 1 and 10 ng/mL showed higher viability compared to control cells. After 18 h of DON (100 ng/mL) exposure, a significantly lower proliferation after mitogen stimulation was observed. In contrast, an increase of spontaneous proliferation induced by DON (100 ng/mL) was detected. After DON exposure, the expression of cytokine genes decreased, with the exception of IL-1ß and IL-8, which increased after 18 h exposure to 100 ng/mL of DON. Among lymphocyte subpopulations, helper T-cells and γδ T-cells exhibiting lower production of IL-17, IFNγ and TNFα were most affected by DON exposure (10 ng/mL). These findings show that subclinical doses of DON lead to changes in immune response.

Identification and determination of deoxynivalenol (DON) and deepoxy-deoxynivalenol (DOM-1) in pig colostrum and serum using liquid chromatography in combination with high resolution mass spectrometry (LC-MS/MS (HR)).

Deoxynivalenol (DON) is one of the most common mycotoxins produced by field fungi (especially Fusarium). Contamination of livestock feed is a significant risk factor, especially for pigs that are highly susceptible to the toxic effects of deoxynivalenol. In this study, validated ultra-high performance liquid chromatography (U-HPLC) combined with a HR-Orbitrap-MS analysis method is described for the identification and quantitative determination of the mycotoxin compounds (DON and deepoxy-deoxynivalenol (DOM-1)) in pig colostrum (milk) and serum. Pre-treatment of the samples involved a deproteinisation step with methanol followed by a purification step by solid phase extraction (HLB cartridges). The chromatographic separation was performed on a C18 column with 1.7 µm-particle size using a water-methanol mobile phase. Detection of analytes was achieved on the tandem hybrid mass spectrometer Q Exactive, with a heated electrospray ionisation probe measured in positive mode (H-ESI+). For the confirmation of identification, a mass spectrometer was utilized in the full scan mode with resolving power (PR) = 140,000 (FWHM) and for quantification analysis, it was utilized in the parallel reaction monitoring mode (PRM). The method has been fully validated according to the requirements of Commission Decision 2002/657/EC for confirmatory analyses, plus the addition of a mass accuracy (MA) parameter. For the confirmation of the presence of these analytes in pig colostrum and serum, matching of the retention time with mass accuracy for the precursor ion from MS and product ions from MS/MS was used. A deuterium isotopically labelled internal standard and a matrix-matched calibration curve were employed for quantification. The linear range of quantification was 0.5-20 µg L-1 and the correlation coefficient (R2) was >0.999 for all calibrations. The limit of detection for DON and DOM-1 in colostrum was 0.48 µg L-1 and 0.54 µg L-1, respectively, and in serum 0.24 µg L-1 and 0.36 µg L-1, respectively. The limit of quantification for DON and DOM-1 in colostrum was 0.80 µg L-1 and 0.89 µg L-1, respectively, and in serum 0.39 µg L-1 and 0.60 µg L-1, respectively. The method was successfully evaluated using the obtained samples of pig colostrum and serum.

African swine fever virus infects macrophages, the natural host cells, via clathrin- and cholesterol-dependent endocytosis.

The main cellular target for African swine fever virus (ASFV) is the porcine macrophage. However, existing data about the early phases of infection were previously characterized in non-leukocyte cells such as Vero cells. Here, we report that ASFV enters the natural host cell using dynamin-dependent and clathrin-mediated endocytosis. This pathway is strongly pH-dependent during the first steps of infection in porcine macrophages. We investigated the effect of drugs inhibiting several endocytic pathways in macrophages and compared ASFV with vaccinia virus (VV), which apparently involves different entry pathways. The presence of cholesterol in cellular membranes was found to be essential for a productive ASFV infection while actin-dependent endocytosis and the participation of phosphoinositide-3-kinase (PI3K) activity were other cellular factors required in the process of viral entry. These findings improved our understanding of the ASFV interactions with macrophages that allow for successful viral replication.

The phenotype and activation status of T and NK cells in porcine colostrum suggest these are central/effector memory cells.

In pigs, the epitheliochorial placenta does not allow transfer of maternally derived antibodies or immune cells to the fetus. Thus, piglets are dependent on intake of colostrum for acquisition of passive immunity during the neonatal period. As well as immunoglobulin G (IgG), cellular components of colostrum, mainly lymphocytes, can enter the systemic circulation and secondary lymphoid organs of the neonate. In order to understand the function and immunological role of these cells, a flow cytometric study was undertaken to characterise the cellular profile and phenotype of T cells and NK cells present in porcine colostrum. The results indicated that the greatest numbers of lymphocytes were found on the first day of lactation. The predominant cell types in colostrum were CD8(+) single positive T cells (53.6%), followed by CD4(+)CD8(+) double positive T cells (21.1%), CD2(+)CD8(+) γδ T cells (15.0%) and NK cells (13.5%). CD4(+) single positive T cells (4.4%) and other γδ T cell subpopulations (1.8% CD2(-)CD8(-) and 0.4% CD2(+)CD8(-)) were present in colostrum at low levels. Although the profile of the T cell subpopulations during the first 3 days of lactation remained constant, the absolute numbers of T and NK cells decreased significantly in the first few hours of lactation. Expression of CCR7, CD11b, CD25, CD45RA and MHC class II was used to assess the activation status of T and NK cells in colostrum. T cell subpopulations expressed markers consistent with an effector memory phenotype, indicating that these were antigen-experienced cells. The phenotype of colostral T and NK cells suggests a role in mucosal immunity and potentially in transfer of passive immunity from sow to piglet.