Cellular and Molecular Mechanisms Underlying the Strong Neonatal IL-12 Response of Lamb Mesenteric Lymph Node Cells to R-848

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Peripheral and placental immune responses in sheep after experimental infection with "Toxoplasma gondii" at the three terms of gestation

P. 1-9Although it is known that gestation could infuence the clinical course of ovine toxoplasmosis, the precise efect of the term of gestation when sheep are infected are yet mostly unknown. The aim of this study was to evaluate the peripheral and placental immune responses developed in pregnant sheep after experimental infection with Toxoplasma gondiiat diferent times of gestation. Thirty‑six pregnant sheep were allocated in diferent groups, orally inocu‑lated with sporulated oocysts of T. gondiiat early, mid and late gestation and culled within 30 days post‑infection. The peripheral humoral and cytokine responses were evaluated, as well as the transcription of cytokines at the placenta. Serological analysis revealed that, regardless the term of gestation when infected, specifc IgG against T. gondiiwere detected from day 8 post‑infection and there was an early peripheral release of IFN‑γ at the frst week post‑infection followed by a short peak of IL10 and TNF‑α at the second week post‑infection. There were no signifcant diferences in this response between infected groups. At the placenta, a similar increase in transcription of IFN‑γ, and TNF‑α was found at the three terms of gestation, while IL‑4 increased mainly at the frst and second terms and IL‑10 transcription was higher at the last term. While these fndings show that both Th1 and Th2 cytokines play a key role in the patho‑genesis of ovine toxoplasmosis and that placental and peripheral immune responses do not closely correlate, there seems to be no clear modulation of these responses along the gestation.S

Experimental ovine toxoplasmosis: influence of the gestational stage on the clinical course, lesion development and parasite distribution

P. 1-14The relation between gestational age and foetal death risk in ovine toxoplasmosis is already known, but the mechanisms involved are not yet clear. In order to study how the stage of gestation influences these mechanisms, pregnant sheep of the same age and genetic background were orally dosed with 50 oocysts of Toxoplasma gondii (M4 isolate) at days 40 (G1), 90 (G2) and 120 (G3) of gestation. In each group, four animals were culled on the second, third and fourth week post infection (pi) in order to evaluate parasite load and distribution, and lesions in target organs. Ewes from G1 showed a longer period of hyperthermia than the other groups. Abortions occurred in all groups. While in G2 they were more frequent during the acute phase of the disease, in G3 they mainly occurred after day 20 pi. After challenge, parasite and lesions in the placentas and foetuses were detected from day 19 pi in G3 while in G2 or G1 they were only detected at day 26 pi. However, after initial detection at day 19 pi, parasite burden, measured through RT-PCR, in placenta or foetus of G3 did not increase significantly and, at in the third week pi it was lower than that measured in foetal liver or placenta from G1 to G3 respectively. These results show that the period of gestation clearly influences the parasite multiplication and development of lesions in the placenta and foetus and, as a consequence, the clinical course in ovine toxoplasmosis.S

Phenotypic and functional analysis of monocyte populations in cattle peripheral blood identifies a subset with high endocytic and allogeneic T-cell stimulatory capacity

International audienceAbstractCirculating monocytes in several mammalian species can be subdivided into functionally distinct subpopulations based on differential expression of surface molecules. We confirm that bovine monocytes express CD172a and MHC class II with two distinct populations of CD14+CD16low/-CD163+ and CD14−CD16++CD163low- cells, and a more diffuse population of CD14+CD16+CD163+ cells. In contrast, ovine monocytes consisted of only a major CD14+CD16+ subset and a very low percentage of CD14−CD16++cells. The bovine subsets expressed similar levels of CD80, CD40 and CD11c molecules and mRNA encoding CD115. However, further mRNA analyses revealed that the CD14−CD16++ monocytes were CX3CR1highCCR2low whereas the major CD14+ subset was CX3CR1lowCCR2high. The former were positive for CD1b and had lower levels of CD11b and CD86 than the CD14+ monocytes. The more diffuse CD14+CD16+ population generally expressed intermediate levels of these molecules. All three populations responded to stimulation with phenol-extracted lipopolysaccharide (LPS) by producing interleukin (IL)-1β, with the CD16++ subset expressing higher levels of IL-12 and lower levels of IL-10. The CD14−CD16++ cells were more endocytic and induced greater allogeneic T cell responses compared to the other monocyte populations. Taken together the data show both similarities and differences between the classical, intermediate and non-classical definitions of monocytes as described for other mammalian species, with additional potential subpopulations. Further functional analyses of these monocyte populations may help explain inter-animal and inter-species variations to infection, inflammation and vaccination in ruminant livestock

Immune Response of Cows Fed Polyunsaturated Fatty Acids under High Ambient Temperatures

The aim of the experiment was to determine the effects of 2 different fat supplementations on immune functions of dairy cows under high ambient temperatures. The experiment involved 24 Italian Friesian cows, divided into 3 groups of 8 animals, that were subjected to fat supplementations based on whole flaxseed (FS) or microencapsulated fish oil (FO). At d 0, 45, and 90 of the experiment, lymphocyte response to phytohemagglutinin (PHA) was determined in vivo on each animal by measurement of skin-fold thickness at the site of PHA injection. A humoral response to chicken egg albumin (OVA) was established following a subcutaneous injection with OVA. To assess cows’ immune responses, plasma was prepared from experimental blood samples taken at d 0, 15, 30, 45, 60, 75, and 90 of the experiment. Plasma samples were measured for the presence of anti-OVA IgG, IL-1β, IL-6, and IL- 10. Results revealed greater skin-fold thickness in cows fed FS compared with the FO and the control groups, corresponding to higher mean lymphocyte proliferation following in vivo PHA injection. Cows fed FS displayed higher titers of anti-OVA IgG than the control and FOfed cows. No effects of the diet on IL-1β or IL-6 were found, whereas IL-10 secretion was lower in FS-fed cows than in control cows. The present study demonstrates that feed supplementation of n-3 polyunsaturated fatty acids can enhance immune responses of dairy cows exposed to high ambient temperatures. Key words: immune function, dairy cow, polyunsaturated fatty acid, high ambient temperatur

Total mixed ration pellets for light fattening lambs: Effects on animal health

9 páginas, 6 tablas.Fifty male Merino lambs (6 to 8 weeks, 14.1 kg; n=10 per group) were used to study the effect of feeding system: barley straw in long form and concentrate pellets in separate troughs (Control), ad libitum alfalfa supplemented with concentrate in separate troughs (Alfalfa) or including various levels of ground barley straw in concentrate pellets (B05, B15 and B25 for 50, 150 and 250 g barley straw/kg), on rumen characteristics, acid-base status, blood cell counts and lymphocyte stimulation. Alfalfa lambs had the heaviest digestive tract contents, highest rumen pH values, lowest volatile fatty acid concentration, highest papillae counts and best mucosa colour and the greatest blood pCO2 values, lowest sodium and chloride and highest potassium concentrations (P<0.05). Including ground barley straw in the concentrate pellet or providing straw in long form separately from the concentrate reduces rumen pH and darkens ruminal mucosa as compared with alfalfa-fed lambs, thus affecting acid-base status. © 2014 The Animal ConsortiumSpanish Ministry of Science and Innovation AGL2010-19094; Council of Castile and Leon ; European Social Fund; Scottish Government Rural & Environment Science & Analytical Services (RESAS) division ; BBSRC: BB/I019863/1 ;BB/I020519/1 ;AbD Serotec; Bio-Rad CompanyPeer Reviewe