Stress-induced immunosuppression increases levels of certain circulating miRNAs and affects the immune response to an infectious bursal disease virus vaccine in chickens

Stress-induced immunosuppression can affect the immune effect of vaccine. However, the mechanism of stress-induced immunosuppression affecting immune response to infectious bursal disease virus (IBDV) vaccine in chicken is still unclear. In this study, thirteen IBDV related circulating miRNAs were selected to study their expressions, possible functions and mechanisms in dexamethasone (Dex)-induced immunosuppressed chicken vaccinated with IBDV attenuated vaccine. The experiment aimed to explore the relationship between the expressions of IBDV related circulating miRNAs and stress-induced immunosuppression. The quantitative real-time PCR (qRT-PCR) results showed that Dex-induced immunosuppression could induce the differential expressions of the candidate serum circulating miRNAs, especially on the 2nd, 5th, 7th and 28th day after dexamethasone treatment. Dex-induced immunosuppression could affect the immune response to the IBDV vaccine, which was possibly achieved by partially regulating the differential expressions of the IBDV related circulating miRNAs. Bioinformatics analysis showed that the candidate miRNAs could regulate the immune function mainly through targeting genes (such as CREB1 and MAPK1) in TGF-β and MAPK signaling pathways. This study can provide a preliminary reference for further studying the function and mechanism of circulating miRNAs in immune regulation.

TMT-based quantitative proteomic analysis reveals the spleen regulatory network of dexamethasone-induced immune suppression in chicks

Stress-induced immunosuppression is one of the most widespread problems in the poultry industry. Understanding the molecular regulatory mechanism of immunosuppression induced by stress in the chicken spleen would provide a scientific foundation for the prevention of stress reactions and antistress molecular breeding in poultry. To assess the protein expression profile of spleen tissue in a stress-included immunosuppression model, we performed a TMT-based proteomic analysis of chicken spleen tissue in a Dex-induced immunosuppression model (group C) and a control group (group A). We identified 590 differentially abundant proteins (DAPs) in chicken spleen tissue. These DAPs were significantly enriched in the following functional categories: ECM-receptor interaction, DNA replication, p53 signaling pathway, PI3K-Akt signaling pathway and NF-kappa B signaling pathway. Integrative analysis of the proteome and our previous transcriptome data revealed 62 DAPs showing correlations with the expression of their encoding mRNAs. Complementary proteome- and transcriptome-level analyses revealed a complex molecular network of stress-included immunosuppression. DPP4 and ALDH1A3 were the most significantly upregulated DAPs. GBP and OASL were identified as important nodes in the network related to stress-induced immunosuppression. The candidate genes identified in this study may be useful for the marker-based breeding of new chicken varieties with reduced stress levels. SIGNIFICANCE: This study provides a large amount of new information about the spleen proteome of the Dex-induced immunosuppression in chicks, as well as the correlation of transcriptome and proteome. Analysis of this resource has enabled us to examine mechanism of protein and transcript diversification, which expands the understanding of the complexity of the mechanism of stress-induced immunosuppression.

Transcriptomic Analysis of Spleen Revealed Mechanism of Dexamethasone-Induced Immune Suppression in Chicks

Stress-induced immunosuppression is a common problem in the poultry industry, but the specific mechanism of its effect on the immune function of chicken has not been clarified. In this study, 7-day-old Gushi cocks were selected as subjects, and a stress-induced immunosuppression model was successfully established via daily injection of 2.0 mg/kg (body weight) dexamethasone. We characterized the spleen transcriptome in the control (B_S) and model (D_S) groups, and 515 significant differentially expressed genes (SDEGs) (Fragments Per Kilobase of transcript sequence per Millions base pairs sequenced (FPKM) > 1, adjusted p-value (padj) < 0.05 and Fold change (|FC|) ≥ 2) were identified. The cytokine-cytokine receptor interaction signaling pathway was identified as being highly activated during stress-induced immunosuppression, including the following SDEGs-CXCL13L2, CSF3R, CSF2RB, CCR9, CCR10, IL1R1, IL8L1, IL8L2, GHR, KIT, OSMR, TNFRSF13B, TNFSF13B, and TGFBR2L. At the same time, immune-related SDEGs including CCR9, CCR10, DMB1, TNFRSF13B, TNFRSF13C and TNFSF13B were significantly enriched in the intestinal immune network for the IgA production signaling pathway. The SDEG protein-protein interaction module analysis showed that CXCR5, CCR8L, CCR9, CCR10, IL8L2, IL8L1, TNFSF13B, TNFRSF13B and TNFRSF13C may play an important role in stress-induced immunosuppression. These findings provide a background for further research on stress-induced immunosuppression. Thus, we can better understand the molecular genetic mechanism of chicken stress-induced immunosuppression.

Impact of Prebiotics and Synbiotics Administered in ovo on the Immune Response against Experimental Antigens in Chicken Broilers

Simple Summary

The immune system of chickens matures in the course of embryonic development. Early in ovo supplementation with bioactive substances leads to the long-term maintenance of a high level of intestine bifidobacteria, reduces the number of detrimental microorganisms in the gut, modulates the central and peripheral lymphatic organ development in broilers, and stimulates gut-associated lymphoid tissues (GALT) development after hatching. In this investigation, we studied whether the early in ovo application (at the 12th day of embryo incubation) of selected bioactives (prebiotics and synbiotics) influences the humoral immune response against experimental antigens, and the delayed-type hypersensitivity (DTH) skin reaction to experimental mitogen. This study demonstrated that the in ovo application of bioactives did not significantly influence the humoral immune response against T-dependent and T-independent model antigens. Prebiotics in chickens immunized with T-dependent antigen (SRBC) protected them from a retarded rise of the IgG concentration. Bioactives reduced the mortality of birds, markedly with inulin (−6.4%), and the DTH reaction to phytohemagglutinin on the 7^th and 21^st day after hatching.

Abstract

The effect of the in ovo application of selected prebiotics and synbiotics on the humoral immune response against T-dependent (SRBC) and T-independent (dextran) antigens and delayed-type hypersensitivity (DTH) to phytohemagglutinin was studied. On the 12th day of incubation, 800 eggs (Ross 308) were divided into five groups and injected into the egg air chamber with prebiotic inulin (Pre1), Bi²tos (Pre2), a synbiotic composed of inulin and Lactococcus lactis subsp. lactis IBB SL1 (Syn1), a synbiotic composed of Bi²tos and L. lactis subsp. cremoris IBB SC1 (Syn2), and physiological saline (control group; C). The chickens were immunized twice at the 7th and 21st day of life with SRBC and dextran. A DTH test was performed on the 7th, 21st, and 35th day. The application of prebiotics and synbiotics had no significant effect on the humoral immune response. SRBC-immunized in ovo Pre1- and Pre2-treated chickens showed significantly higher serum IgG levels than the control. A significant effect on the DTH reaction was detected on the 7th (Pre1 < C) and 21st (Pre2 > Syn2) day. However; Bi²tos may transiently stimulate the cellular immune response on the 21st day. It may be concluded that the application of inulin in an egg air chamber on the 12th day of incubation may stimulate the secondary immune response. The inulin-treated group exhibited a lower mortality rate than the control group.

Effect of dexamethasone on bacteriostatic activity of turkey monocytes and implications for food safety

Stress has been shown to affect the immune system of turkeys making them more susceptible to bacterial infections. Five-week-old male and female turkeys were treated with 3 intra-muscular injections of dexamethasone (Dex) at 0, 0.5 and 2.0mg/kg body weight. Twenty-four hours after the third injection birds were bled and white blood cell (WBC) differentials and bacteriostatic activity of monocytes were measured. Dex at both 0.5 and 2.0mg/kg decreased phagocytic activity in females only. Bacteriostatic activity was decreased at both concentrations of Dex at 8 and 16 h post-infection in both sexes and was lower in males as compared to females. Total WBC counts were increased in females at both concentrations of Dex whereas male total WBC counts were unaffected. Both males and females had an increase in the heterophil to lymphocyte ratio. Within the same study, replicate pens of turkeys were challenged with intra-air sac inoculation of 100 cfu of Escherichia coli. Isolation of E. coli was significantly increased by both Dex and E. coli challenge, but there were no differences between sexes. These results suggest that stress can compromise the bacteriostatic activity of turkey monocytes and increase bacterial colonization of blood and tissues, potentially affecting food safety.

Oral administration of immunopotentiator from Pantoea agglomerans 1 (IP-PA1) improves the survival of B16 melanoma-inoculated model mice

To investigate the usefulness of the immunopotentiator from Pantoea agglomerans 1 (IP-PA1) as a supportive drug in melanoma therapy, we analyzed the immunological effects of IP-PA1 on melanoma-inoculated model mice. Oral administration of IP-PA1 increased the serum levels of tumor necrosis factor (TNF)-α at 2 h after the administration and interferon (IFN)-γ and IL-12 at 12 h after the administration in naïve BALB/cCrSlc mice as evaluated by ELISA. IP-PA1 did not affect the proliferation of melanoma cells directly determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Combinatory treatment of IP-PA1 with doxorubicin for 9 days increased the serum levels of IFN-γ and IL-12 by 71.0 and 15.3%, respectively, compared to the treatment of doxorubicin alone in melanoma-bearing C57BL/6NCrSlc mice as evaluated by ELISA. It also increased the proportion of natural killer (NK) cells and the ratio of CD4(+) to CD8(+) T cells in the spleen from 6.1 ± 0.3 to 7.4 ± 0.5% and from 1.25 ± 0.03 to 1.38 ± 0.04, respectively, compared to the treatment of doxorubicin alone as analyzed by flow cytometry. The mean survival period of melanoma-bearing, doxorubicin treated mice was prolonged from 31.4 ± 7.1 to 35.3 ± 8.4, 51.1 ± 5.4, and 45.0 ± 8.4 days by combinatory treatment of IP-PA1 at the daily doses of 0.1, 0.5, and 1 mg/kg, respectively. In conclusion, the results of the present study suggest the usefulness of IP-PA1 as a supportive drug in melanoma therapy.