CD11d is a novel antigen on chicken leukocytes

TMT-based proteomic analysis reveals integrins involved in the synergistic infection of reticuloendotheliosis virus and avian leukosis virus subgroup J

BACKGROUND

Co-infection with the avian leukosis virus subgroup J (ALV-J) and the reticuloendotheliosis virus (REV) increases mutual viral replication, causing a more serious pathogenic effect by accelerating the progression of neoplasia and extending the tumor spectrum. However, the molecular mechanism underlying the synergistic replication of ALV-J and REV remains unclear.

RESULTS

Here, we performed this study to compare the differentially expressed proteins among CEF cells infected with ALV-J, REV or both at the optimal synergistic infection time using TMT-based quantitative proteomics. We identified a total of 719 (292 upregulated and 427 downregulated) and 64 (35 upregulated and 29 downregulated) proteins by comparing co-infecting both viruses with monoinfecting ALV-J and REV, respectively. GO annotation and KEGG pathway analysis showed the differentially expressed proteins participated in virus-vector interaction, biological adhesion and immune response pathways in the synergistic actions of ALV-J and REV at the protein levels. Among the differentially expressed proteins, a large number of integrins were inhibited or increased in the co-infection group. Further, eight integrins, including ITGα1, ITGα3, ITGα5, ITGα6, ITGα8, ITGα9, ITGα11 and ITGβ3, were validated in CEF cells by qRT-PCR or western blot.

CONCLUSIONS

These findings proved that integrins may be key regulators in the mechanism of synergistic infection of REV and ALV-J, which will provide more insight into the pathogenesis of synergism of REV and ALV-J at protein level.

The Evaluation of Cellular Immunity to Avian Viral Diseases: Methods, Applications, and Challenges

Cellular immune responses play critical roles in the control of viral infection. However, the immune protection against avian viral diseases (AVDs), a major challenge to poultry industry, is yet mainly evaluated by measuring humoral immune response though antibody-independent immune protection was increasingly evident in the development of vaccines against some of these diseases. The evaluation of cellular immune response to avian viral infection has long been neglected due to limited reagents and methods. Recently, with the availability of more immunological reagents and validated approaches, the evaluation of cellular immunity has become feasible and necessary for AVD. Herein, we reviewed the methods used for evaluating T cell immunity in chickens following infection or vaccination, which are involved in the definition of different cellular subset, the analysis of T cell activation, proliferation and cytokine secretion, and in vitro culture of antigen-presenting cells (APC) and T cells. The pros and cons of each method were discussed, and potential future directions to enhance the studies of avian cellular immunity were suggested. The methodological improvement and standardization in analyzing cellular immune response in birds after viral infection or vaccination would facilitate the dissection of mechanism of immune protection and the development of novel vaccines and therapeutics against AVD.

The Interplay between Salmonella and Intestinal Innate Immune Cells in Chickens

Salmonellosis is a common infection in poultry, which results in huge economic losses in the poultry industry. At the same time, Salmonella infections are a threat to public health, since contaminated poultry products can lead to zoonotic infections. Antibiotics as feed additives have proven to be an effective prophylactic option to control Salmonella infections, but due to resistance issues in humans and animals, the use of antimicrobials in food animals has been banned in Europe. Hence, there is an urgent need to look for alternative strategies that can protect poultry against Salmonella infections. One such alternative could be to strengthen the innate immune system in young chickens in order to prevent early life infections. This can be achieved by administration of immune modulating molecules that target innate immune cells, for example via feed, or by in-ovo applications. We aimed to review the innate immune system in the chicken intestine; the main site of Salmonella entrance, and its responsiveness to Salmonella infection. Identifying the most important players in the innate immune response in the intestine is a first step in designing targeted approaches for immune modulation.

Analysis of chicken intestinal natural killer cells, a major IEL subset during embryonic and early life

Restrictions on antimicrobials demand alternative strategies to improve broiler health, such as supplying feed additives which stimulate innate immune cells like natural killer (NK) cells. The main objective of this study was to characterize intestinal NK cells in broiler chickens during embryonic and early life and compare these to NK cells in spleen, blood and bone marrow. Also T-cell subsets were determined. The majority of intestinal NK cells expressed IL-2Rα rather than 20E5 and 5C7, and showed low level of activation. Within intestinal NK cells the activation marker CD107 was mostly expressed on IL-2Rα⁺ cells while in spleen and blood 20E5⁺ NK cells primarily expressed CD107. High percentages of intestinal CD8αα⁺, CD8αβ⁺ and from 2 weeks onward also gamma delta T cells were found. Taken together, we observed several intestinal NK subsets in broiler chickens. Differences in NK subsets were mostly observed between organs, rather than differences over time. Targeting these intestinal NK subsets may be a strategy to improve immune-mediated resistance in broiler chickens.