Differential expression of pro-inflammatory and anti-inflammatory cytokines during experimental infection with low or high virulence bovine viral diarrhea virus in beef calves

The objective was to compare the mRNA expression of pro-inflammatory (TNF-α, IL-1β, IFN-γ, IL-2, IL-12, IL-15) and anti-inflammatory (IL-4, IL-10, TGF-β) cytokines, after experimental infection with low or high virulence noncytopathic (ncp) bovine viral diarrhea virus (BVDV). Thirty BVDV-naïve, beef calves were intranasally inoculated with low (LV; n = 10, SD-1) or high (HV; n = 10, 1373) virulence ncp BVDV or with BVDV-free cell culture medium (Control, n = 10). Calves were euthanized on day 5 post-inoculation, and tracheo-bronchial lymph node and spleen samples were collected for mRNA expression through quantitative-RT-PCR. mRNA levels of pro-inflammatory (TNF-α, IL-1β, IL-2, IFN-γ) and anti-inflammatory (IL-4 and IL-10) cytokines were up-regulated in tracheo-bronchial lymph nodes of HV, but not in LV, compared to the control group (P < 0.05). IL-12 mRNA level was up-regulated in tracheo-bronchial lymph nodes of both LV and HV groups (P ≤ 0.05). A significant up-regulation of IL-15 mRNA was observed in tracheo-bronchial lymph nodes for LV calves (P < 0.002), but not for HV calves. Experimental inoculation with BVDV-2 1373 stimulated significant mRNA expression of pro-inflammatory and anti-inflammatory cytokines. In contrast, inoculation with BVDV-1a SD-1 only resulted in up-regulation of IL-12 and IL-15 mRNA, which is associated with activation of macrophages and NK cells during innate immune response.     

The influence of oral bacteria on tissue levels of Toll-like receptor and cytokine mRNAs in feline chronic gingivostomatitis and oral health

Feline chronic gingivostomatitis (FCGS) is an inflammatory disease of the oral cavity that causes severe pain and distress in affected cats. Treatment methods are currently very limited. The aims of this study were to assess the feline innate immune response by investigating the levels of cytokine and Toll-like receptor (TLR) mRNAs in tissue biopsies of cats with and without FCGS, and to relate this to the presence or absence of putative oral pathogens identified previously within these cats. Mucosal biopsies were collected from 28 cats with FCGS and eight healthy cats. The levels of TLR (TLR2, TLR3, TLR4, TLR7, TLR9) and cytokine (IL-1β, IL-4, IL-6, IL-10, IL-12, TNF-α, IFN-γ) mRNA was determined using quantitative PCR. In the FCGS group a statistically significant increase was seen in TLR2, TLR7, TNF-α, IFN-γ, IL-1β and IL-6 mRNA levels compared to the healthy group. In cats where Tannerella forsythia was present, statistically significant increases were seen in TLR2, TLR4, TLR7, TLR9, TNF-α and IL-1β mRNA levels compared to cats where this putative pathogen was absent. Statistically significant increases in mRNA expression were also seen in cats harbouring feline calicivirus (FCV) (TLR2, IL-1β, IL-6, IFN-γ) and Porphyromonas circumdentaria (TLR2, TLR3) compared to cats where these putative pathogens were absent. Pasteurella multocida subsp. multocida and Pseudomonas sp. did not significantly alter the expression of any TLR or cytokine mRNAs when compared to animals who tested negative for these species, while cats colonised with P. multocida subsp. septica demonstrated a statistically significant reduction in the expression of TLR7, TNF-α and IFN-γ mRNAs compared to cats free of this species. The expression of mRNA for several TLRs and cytokines is elevated in FCGS. A positive correlation was observed between clinical disease severity and the presence of FCV (p = 0.001; Rho = 0.58). Although the number of cats harbouring T. forsythia was low by comparison, 80% of samples in which it was present were from cases with the highest clinical disease severity. Positive correlations with clinical disease severity were seen for TLR2 (p = 0.00086), TLR7 (p = 0.049), TNF-α (p = 0.027), IFN-γ (p = 0.0015), IL-1β (p = 0.004) and IL-6 (p = 0.00001) mRNAs. The putative pathogens FCV and T. forsythia may be important in stimulating a host immune response to FCGS and may play a role in the pathogenesis of this disease.     

Classical swine fever virus suppresses maturation and modulates functions of monocyte-derived dendritic cells without activating nuclear factor kappa B

Classical swine fever virus (CSFV) compromises the host immune system, causing the severe disease of pigs. Dendritic cells (DCs) are the most potent inducers of immune responses. In the present study, we investigated the functional properties of porcine monocyte-derived DCs (Mo-DCs) affected by CSFV. Results showed that the expression of surface markers of DCs such as major histocompatibility complex class II (MHC-II), CD80, CD83 and CD86 were unimpaired, but an obviously increased expression of CD172a in DCs was noticed 48 h after CSFV infection. The expression profiles of cytokines were detected in cultured Mo-DCs after various treatments for 48 h by Q-RT-PCR. The findings suggested that CSFV infection significantly increased the mRNA expression of IL-10 and TNF-α, and inhibited IL-12 expression, with little effect on IFN-α and IFN-γ expression. We further demonstrated that CSFV was incapable of activating the nuclear factor kappa B (NF-κB) in infected DCs, which was characterized by an unvaried DNA binding activity of NF-κB, the lack of translocation of p65/RelA from the cytoplasm to the nucleus and the stabilization of p65/RelA expression. Furthermore, Western blot analysis indicated that the inactivation of NF-κB was due to the failure of IκBα degradation. The data demonstrated that CSFV could be replicated in DCs and CSFV infection could modulate the secretion of crucial co-stimulatory molecules and cytokines which down-regulated maturation of DCs, without activating NF-κB in DCs. Thus, the results suggested a possible mechanism for CSFV evasion of innate host defenses, providing the basis for understanding molecular pathways in CSFV pathogenesis.     

Microsphere immunoassay for the detection of cytokines in domestic cat (Felis catus) plasma: elevated IL-12/23 in acute feline immunodeficiency virus infections

We recently described the development and validation of a highly sensitive and specific microsphere immunoassay capable of simultaneously quantifying three domestic cat cytokines in tissue culture supernatant. Here we describe the modification of this assay to measure interferon gamma (IFNγ), interleukin (IL)-10 and IL-12/IL-23 p40 (IL-12/23) in domestic cat plasma, report values obtained from plasma collected after feline immunodeficiency virus (FIV) exposure, and compare plasma concentrations to blood cell mRNA expression. The validated quantitation limits of this assay are 31–1000 pg/ml for IFNγ, 63–2000 pg/ml for IL-10, and 20–625 pg/ml for IL-12/23. Plasma cytokine levels from domestic cats infected with pathogenic and/or apathogenic FIV were determined at 3–4 and 7–8 weeks post-infection. IL-12/23 was elevated (p < 0.05) during acute infection with both FIV strains in two similar studies, conducted five years apart in different feline cohorts (n = 44 total animals). IL-12/23 concentrations ranged from 377 to 1904 pg/ml in naïve cats and 552 to 3460 pg/ml in infected cats. In contrast, the majority of plasma samples had IFNγ and IL-10 concentrations below the lowest standard tested. The inability to consistently detect levels of IFNγ and IL-10 in plasma, despite the fact that mRNA changes were detected, suggests that these cytokines may be secreted and/or cleared in a more highly regulated manner than IL-12/23, or perhaps exert local effects under tighter peripheral constraints and/or at a lower effective concentration.     

Differential gene expression of proinflammatory chemokines and cytokines in lungs of ascites-resistant and -susceptible broiler chickens following intravenous cellulose microparticle injection

Intravenous injection of microparticles (MPs) is a tool to reveal susceptibility to pulmonary hypertension (PH) syndrome (PHS, ascites) in broilers. After injection MPs get lodged in pulmonary arterioles and cause localized inflammation. To examine the expression of chemokines/cytokines during the MP-induced pulmonary inflammatory response, lungs were collected from 4-week-old broilers (6/line/time point) from the PHS-resistant (RES) and -susceptible (SUS) broilers before (0 h) and after (2, 6, 12, 24, and 48 h) MP injection and analyzed using quantitative RT-PCR. In both lines, expression of interleukin-1β (IL-1β), IL-6, IL-8, and K60 increased from 0 to 6 h, reached peak levels at 6 and 12 h, and decreased thereafter, whereas IL-4 and interferon gamma (IFN-γ) expression remained elevated past 12 h. Lungs from the RES line broilers had higher expression (P < 0.05) of IL-1β and IL-6 at 2, 6, and 12 h; higher IL-8 at 6 and 12 h; higher K60 at 6, 12, and 24 h; higher IL-4 at 12, 24, and 48 h and higher IFN-γ expression at 6 and 48 h post-MP injection than SUS line broilers. Higher expression of chemokines/cytokines in RES compared to SUS line lungs may explain the ability of RES line broilers to effectively counteract the MP-induced PH and resolve the vascular occlusion.     

Rapid NK-cell activation in chicken after infection with infectious bronchitis virus M41

Natural killer (NK) cells are cytotoxic lymphocytes and play an important role in the early defence against viruses. In this study we focussed on NK cell and interferon (IFN) responses after infection with infectious bronchitis virus (IBV). Based on surface expression of CD107+, enhanced activation of lung NK cells was observed at 1 dpi, whereas in blood prolonged NK-cell activation was found. IFN-α and IFN-β mRNA and proteins were not rapidly induced whereas IFN-γ production in lung, measured by Elispot assay, increased over time at 2 and 4 dpi. In contrast, IFN-γ production in blood was highest at 1 dpi and decreased over time down to levels comparable to uninfected birds at 4 dpi. Collectively, infection with IBV-M41 resulted in activation of NK cells in the lung and blood and rapid production of IFN-γ and not IFN-α and IFN-β compared to uninfected birds.     

Rough virulent strain of Brucella ovis induces pro- and anti-inflammatory cytokines in reproductive tissues in experimentally infected rams

The ovine brucellosis caused by Brucella ovis has tropism for reproductive tissues but until now the mechanism of bacterial persistence is not understood. Cytokine expression profiles were studied for 8 months in rams after being experimentally infected with the rough virulent strain of B. ovis (R-B. ovis) to study the pathogenesis of B. ovis and immune mechanism possibly associated to bacteria tropism and persistence. The messenger RNA (mRNA) expression levels of interleukin-1α (IL-1α), IL-1β, IL-6, IL-10, IL-12, interferon-γ (INF-γ) and tumour necrosis factor-α (TNF-α) cytokines were quantified by real-time quantitative RT-PCR (qRT-PCR) in reproductive tissues (epididymus, testicles, ampolae, vesicular glands and bulbourethral glands), and non-reproductive (liver, spleen and kidneys) tissues at 30, 60, 120 and 240 days post infection (dpi). During the acute phase of infection at 30 dpi, the host immune response was most notable demonstrating an up-regulation of several cytokines in reproductive tissues, including the epididymus (IL-6, IL-1β and IL-1α), testicles (INF-γ and IL-12), bulbourethral glands (IL-6 and TNF-α) and ampolae (INF-γ, IL-10, IL-1β and IL-1α). During the development of infection, cytokine gene expression levels decreased, providing evidence of immunosuppression and evidence of immune evasion that favoured persistence of chronic R-B. ovis infection. During the chronic phase of R-B. ovis infection (120 and 240 dpi), cytokine production was down-regulated in the epididymus (IL-1β and IL-1α), testicles (INF-γ and IL-12), and ampolae (INF-γ, IL-10, IL-1β and IL-1α), with the exception of the bulbourethral glands (IL-6 and TNF-α) and epididymus (IL-6); in these tissues, R-B. ovis infection resulted in up-regulation of the pro-inflammatory cytokine IL-6. Herein, we report cytokine expression profiles in tissues of rams experimentally infected with the rough strain of B. ovis, which are associated with bacterial persistence and macrophage activation.     

Transportation stress alters the expression of immunoregulatory cytokines in the porcine thymus

This study investigated the effects of transportation stress on blood concentrations of the main pro-inflammatory cytokines (interleukins IL-1β, IL-2 and IL-6; tumour necrosis factor-α) and anti-inflammatory cytokines (IL-4 and IL-10) and the expression of these cytokines and their receptors in the thymus. Pigs were assessed after 1, 2 and 4 h of transportation (n = 5 per group), with normal housing conditions as a control (n = 4). Serum concentrations of IL-2, IL-6 and IL-10 were highest at 1 h, whereas concentrations of IL-6 and IL-10 were significantly decreased at 4 h. Expression of these three cytokines and their receptors was also significantly altered in the thymus during transportation stress. Serum IL-10 concentrations and thymus IL-10 mRNA expression were significantly correlated. The thymus may contribute towards the regulation of cytokines in pigs during transportation.     

Development of a cytometric bead array screening tool for the simultaneous detection of pro-inflammatory cytokines in porcine plasma

Lipopolysaccharide (LPS) has been widely used as a model of immune challenge in pigs as it induces the immediate synthesis of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6, which trigger the production of the acute phase proteins (APPs) C-reactive protein (CRP), haptoglobin (Hp) and pig-Major Acute Phase Protein (pig-MAP). To measure secreted proteins in porcine plasma, specific and sensitive Enzyme-Linked Immuno Sorbent Assays (ELISAs) are well-suited to perform single parameter analysis, yet this approach is time-consuming and expensive for multi-parameter analyses. During the last decade, multiplex bead-based flow cytometry has been increasingly applied as it offers the opportunity to estimate protein ratios in a small sample volume. Cytometric bead array (CBA) is a flow cytometric application using a diversity of beads with unique fluorescence intensities, covalently coupled to a capture antibody for each protein of interest. Detection antibodies, either directly or indirectly conjugated to a fluorochrome, are added to accomplish the desired sandwich format. The aim of the present study was to develop a CBA 3-plex assay for the major pro-inflammatory cytokines TNF-α, IL-1β and IL-6, and an additional CBA 2-plex assay for the major APPs, CRP and pig-MAP, in porcine plasma. Results were compared to commercial ELISA kits. For the CBA 3-plex assay, the limits of detection (LODs) varied between 0.005 and 0.363 ng/mL, the intra- and inter-assay coefficients of variation were <10% and <16%, respectively. For TNF-α, IL-1β, IL-6 and pig-MAP, CBA time-concentration profiles similar to those obtained with commercial ELISAs were observed. In conclusion, the novel validated CBA 3-plex assay provides a fast and economical screening tool for determination of pro-inflammatory cytokine profiles in limited porcine plasma volumes. This tool will be applied to study the immunomodulatory properties of drugs in a porcine LPS inflammation model. This study also demonstrated the applicability of CBA for measurement of APPs in pigs, although a different combination than pig-MAP with CRP is recommended.     

Effects of inoculum size on cell-mediated and humoral immune responses of foals experimentally infected with Rhodococcus equi: A pilot study

The objective of this pilot study was to compare the cytokine profile as well as cell-mediated and antibody responses of foals infected with a low inoculum of virulent Rhodococcus equi resulting in subclinical pneumonia to that of foals infected with a high inoculum resulting in severe clinical pneumonia. The mean (±SD) ratio of post-infection to pre-infection anti-R. equi IgG(T) concentration was significantly (P = 0.002) higher in foals infected with the high inoculum (195 ± 145; range 62–328) compared to foals infected with the low inoculum (3.9 ± 4.5; range 0.5–11). Similarly, mean (±SD) ratio of post-infection to pre-infection IgM concentration was significantly (P = 0.002) higher in foals infected with the high inoculum (12 ± 4.0; range 7.4–14) compared to foals infected with the low inoculum (2.5 ± 1.5; range 1.2–4.7). Proliferative responses to R. equi antigens as well as expression of mRNA for IL-2, IL-4, IL-10, and IFN-γ in BLN were not significantly different between the two groups. There was a tendency (P = 0.073) towards a higher IFN-γ/IL-4 ratio in the low inoculum group. This study demonstrates that the size of inoculum modulates the IgG subisotype response and possibly the cytokine profile of foals.     

Immune response of AA broilers to IBV H120 vaccine and sodium new houttuyfonate

In this report, 120 healthy one-day-old AA broilers were divided into six groups. Groups 1–4 received 100, 200, 400 and 800 mg/L of sodium new houttuyfonate (SNH) with IB vaccine H120 respectively. Group 5 received PBS and H120 and group 6 IL-2 and H120. The chickens were inoculated at 7 and 14 days of age. On 0, 7, 14, 21, 28 and 35 post first vaccination, the dynamic changes of peripheral lymphocyte proliferation, cytokine assays and serum antibody titers were assayed respectively by MTT method, ELISA and hemagglutination inhibition assay (HI). The results showed that sodium new houttuyfonate significantly raised IB antibody titer in the chickens and also markedly promoted lymphocyte proliferation. The serum levels of IFN-γ and IL-4 in groups 1–4 were higher than those in groups 5 and 6. Hence, the immunologic enhancement of SNH was slightly superior to that of IL-2 adjuvant. Following challenge with IBV, chickens inoculated with SNH showed fewer and less severe clinical signs, lower death rate and less kidney pathology, as compared to those of the control groups. It indicated that SNH could enhance immune responses and increase protection against virulent IBV challenge in chickens.     

Enhancement of humoral and cellular immunity in mice against Japanese encephalitis virus using a DNA prime–protein boost vaccine strategy

A synthetic multi-epitope gene containing critical epitopes of the Japanese encephalitis virus (JEV) envelope gene was cloned into both prokaryotic and eukaryotic expression vectors. The recombinant plasmid and purified recombinant protein (heterologously expressed in Escherichia coli) were used as immunogens in a mouse model. The results indicate that both the recombinant protein and the DNA vaccine induce humoral and cellular immune responses. Neutralising antibody titres in mice in the pcDNA-TEP plus rEP group increased considerably relative to mice immunised using either pcDNA-TEP or rEP alone (P < 0.05). Furthermore, the highest levels of interleukin (IL)-2, interferon-γ and IL-4 were induced following priming with the DNA vaccine and boosting with the recombinant protein. Together these findings demonstrate that a DNA-recombinant protein prime-boost vaccination strategy can produce high levels of antibody and trigger significant T cell responses in mice, highlighting the potential value of such an approach in the prevention of JEV infection.     

Butyrylcholinesterase as a marker of inflammation and liver injury in the acute and subclinical phases of canine ehrlichiosis

The aim of this study was to evaluate the role of butyrylcholinesterase (BChE) as a marker of inflammation and liver injury in the acute and subclinical phases of canine ehrlichiosis. Forty-two serum samples of dogs naturally infected with Ehrlichia canis were used, of which 24 were from animals with the acute phase of the disease and 18 with subclinical disease. In addition, sera from 17 healthy dogs were used as negative controls. The hematocrit, BChE activity, hepatic injury (alanine aminotransferase (ALT) and aspartate aminotransferase (AST)), nitric oxide, and cytokines levels were evaluated. The BChE activity was significantly elevated (P < 0.05) in dogs with the acute phase of the disease when compared to healthy animals. However, there was a reduction on BChE activity on dogs with subclinical disease compared to the other two groups. AST and ALT levels were significantly higher (P < 0.05) in the acute phase, as well as the inflammatory mediators (NO_x, TNF-α, INF-γ, IL-4, IL-6) when compared to the control group. On the other hand, IL-10 levels were lower in the acute phase. Based on these results, we are able to conclude that the acute infection caused by E. canis in dogs leads to an increase on seric BChE activity and some inflammatory mediators. Therefore, this enzyme might be used as a marker of acute inflammatory response in dogs naturally infected by this bacterium.     

猪流感病毒A/swine/Guangdong/2/2012(H1N1)毒株攻毒BALB/c小鼠细胞因子动态变化的研究

为了测定H1N1亚型猪流感病毒(swine influenza virus,SIV)对小鼠的致病性,本试验对A/swine/Guangdong/2/2012(H1N1)株SIV HA基因进行克隆及遗传分析,并将SIV尿囊液经鼻腔感染6周龄BALB/c小鼠,观察感染后小鼠的一般状况、器官系数和组织病理学变化,在病毒感染后第1、3和7天使用荧光定量PCR测定小鼠肺脏、脾脏、脑组织中7种细胞因子mRNA的表达量,研究其对小鼠的致病特性。结果显示,该病毒属于经典SIV,病毒经鼻腔感染后可引起小鼠活动减少、采食量降低,但无咳嗽和死亡;病理组织学变化为肺间隔较正常组织明显增厚,毛细血管明显扩张充血,周围肺泡腔呈代偿性肺气肿;小鼠肺脏、脾脏组织样本中IFN-α、IFN-β、IP-10、IL-1β、TNF-α、IRF-3和IL-10 mRNA含量在感染后第3天均显著升高(P<0.05),而脑组织样本中IL-1β和IL-10在小鼠攻毒后第3和7天均显著上调(P<0.05)。     

Giardia and Cryptosporidium infections in neonatal reindeer calves: Relation to the acute phase response

This longitudinal observational study was conducted to investigate the spontaneous effect of Giardia and Cryptosporidium infections on acute phase response (APR) in reindeer calves (Rangifer tarandus tarandus) in Finnish Lapland.Serum (n = 609) and faecal samples (n = 366) were collected from 54 reindeer calves aged zero to 33 days. The samples were analysed for Giardia, Cryptosporidium, acute phase proteins (APP) and γ-globulins.Linear regression models were used to investigate associations of early Giardia infection (before 12 days of life) with the response of APPs and acquiring of passive immunity.Giardia was detected in 100% and Cryptosporidium in 23% of calves. There was a negative association between early Giardia infection and γ-globulin concentrations (p = 0.032) and a positive association with serum amyloid A (SAA) concentrations (p = 0.042). The results suggest a protective effect of colostrum against Giardia infection and that early infection may induce activation of APR.     

Impact of diet on development of bronchial-associated immunity in the neonatal piglet

Bronchial-associated immune development is critically important to protect neonates from respiratory infections. Herein, bronchial-associated immune development in formula-fed and sow-reared pigs is described. Colostrum-fed newborn piglets were fed medicated sow milk replacer formula beginning at 48 h of life or remained with the sow. Blood and tissues were sampled at one-week (d7) and three-weeks (d21) of age. Lymphocyte subpopulations, including T helper 2, cytotoxic T, memory T, and NK cells, in peripheral blood, mediastinal lymph nodes, and thoracic lymph nodes were identified using flow cytometry. Additionally, IL-1β, IL-6, IL-12, TNFα, TGF-β1, TGF-β2, IFNα, IFNβ, and dectin gene expression were analyzed by quantitative RT-PCR. Total IgG, IgM, and IgA concentrations in serum were analyzed. Dietary and developmental effects were observed. This set of baseline measurements provides a framework for future respiratory challenge studies where the effects of diet on the neonate's ability to resist and/or recover from infection can be tested.     

Development of an improved ESAT-6 and CFP-10 peptide-based cytokine flow cytometric assay for bovine tuberculosis

Control of bovine tuberculosis (bTB) continues to be a problem world-wide because of difficulties in identifying infected animals at all stages of infection. The use of the IFN-γ release assays (IGRA) as an ancillary test with the tuberculin skin tests has improved the ability to identify infected animals. However, infected animals may still be missed. The objective of the present study was to evaluate a rapid flow-cytometric assay based on intracellular cytokine staining as an alternative to the in vitro IFN-γ release assay (IGRA). Antigen-specific cells producing IFN-γ were identified after a 6 h stimulation with PPD-B, PPD-A and ESAT-6/CFP-10. Defined groups of animals naturally infected with Mycobacterium bovis (Mbv), animals infected with non-tuberculous mycobacteria (NTM), and uninfected control animals were analysed to evaluate the sensitivity and specificity of the optimized assay. Both antemortem and postmortem diagnostic tests were carried out to verify the status of infection. We show that IFN-γ is induced in T cells from whole blood samples from cattle infected with Mbv 6 h post stimulation with PPD-B, PPD-A and ESAT-6/CFP-10, whereas non-infected animals did not respond. Four colour flow cytometric analysis demonstrated responding cells were CD45R0⁺CD69⁺CD4⁺ memory T cells. Also, the response to stimulation with ESAT-6/CFP-10 can be used to distinguish between cattle infected with Mbv and cattle exposed to NTM. Although further studies are needed, the results indicate that detection of intracellular IFN-γ may represent an important alternative approach for improved method of detection of cattle secreting IFN-γ below levels of detection in culture medium.     

The impact of weight loss on circulating cytokines in Beagle dogs

Chronic low-grade inflammation in obesity is characterized by an increased production of pro-inflammatory and chemotactic cytokines that are contributing to insulin resistance and related co-morbidities. Cytokines act in networks and exhibit pleiotropic effects so we investigated the circulating levels of a wide array of cytokines (pro and anti-inflammatory, chemotactic and growth factors) in a canine model of weight loss. The dogs served as their own control in order to study the impact of weight loss independent of potential confounding factors, such as history of excess weight or gender. While low-grade inflammation had been previously investigated in obese dogs by measuring changes in adipokines, acute phase proteins and key pro-inflammatory cytokines, to the best of our knowledge this is the first study to evaluate how weight loss impacts a wide array of circulating cytokines.Eighteen overweight Beagle dogs were recruited (six spayed females and 12 neutered males), and none of them were grossly obese according to the body condition score (BCS). All the dogs reached an ideal weight by the end of the program. Parameters were assessed before (baseline), at mid-point (month 3) and at end-point (month 6). Plasma GM-CSF, IL-2, Il-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, IFNγ, IP-10, TNFα, monocyte chemotactic protein 1 (MCP-1), keratinocyte chemokine (KC) were measured with canine multiplex immunoassays. Fat mass was assessed by dual energy X-ray absorption (DEXA).Several cytokines decreased throughout the weight loss program (p < 0.01) and were correlated with the percentage of fat measured by DEXA (p < 0.05): chemotactic (MCP-1), growth factors (GM-CSF, IL-7 and IL-2), and pro-inflammatory (KC and IL-18). We could not show trends for several cytokines, possibly because their level may be lower than the assay sensitivity: anti-inflammatory (IL-4 and IL-10), and pro-inflammatory (IL-6 and TNFα).In conclusion, while our findings for several pro-inflammatory and chemotactic cytokines are in accordance with human and rodent studies, we may have identified additional cytokines, such as growth factors, related to obesity-induced low-grade inflammation. Considering the weight loss was enabled by an adjusted diet, the role of this association of cytokines in insulin resistance and related co-morbidities needs to be clarified. Our results could help better understand the cytokine biology in dogs, and as such are relevant for further elucidating the relationship between immune function and metabolism/nutrition.