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An Introduction to the Immune System and Vaccines
Published in Patricia G. Melloy, Viruses and Society, 2023
Scientists can get even more specific in the classification of these lymphocytes based on the types of proteins displayed on the cell surface of the white blood cell (Nicholson 2016). Lymphocytes can be found concentrated in lymph nodes as well as moving around the body using lymphatic or blood vessels (Ross and Pawlina 2011). Two major T cell types include CD4+ helper T and CD8+ cytotoxic T lymphocytes (Lostroh 2019). The name “T cell” comes from the word “thymus,” a major site where T cells mature. The name “B cell” comes from “bursa of Fabricius,” a type of lymphatic tissue in birds like the bone marrow and gut-associated lymphatic tissue in humans. Studies in chicken embryos indicated that the bursa of Fabricius was critical for B cell formation and humoral immunity (Ross and Pawlina 2011). Another special type of white blood cell, the natural killer (NK) cell, is relevant for the response to viral infection (Coico and Sunshine 2015).
Comparative Immunology
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Birds are also characterized by possessing a bursa of Fabricius. The bursa of Fabricius is a lymphoid organ found only in birds. It is a round sac located just above the cloaca. Like the thymus, the bursa reaches its greatest size in the chick about one to two weeks after hatching and then gradually shrinks. Like the thymus, the bursa consists of lymphocytes embedded in epithelial tissue. This epithelial tissue lines a hollow sac connected to the cloaca by a duct. Inside the sac, folds of epithelium extend into the lumen, and scattered through the folds are lymphoid follicles containing lymphocytes, plasma cells, macrophages, and epithelial cells.
Family Birnaviridae
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Concerning expression in plants, Wu H et al. (2004a) achieved efficient synthesis of the VP2 protein in Arabidopsis thaliana. Wu J et al. (2007) produced the VP2 protein in rice seeds. Both products were soluble and suitable for oral delivery in chickens, while no indications on the putative assembly of the VP2 protein were achieved. Marusic et al. (2021) expressed the His-tagged VP2 in Nicotiana benthamiana and revealed the presence of a mixed population of differently shaped particles ranging from spherical capsids, with a diameter between ~25 and ~70 nm, to tubular structures, with variable length from 100 to 400 nm. The intramuscular injection of such putative VP2 VLPs induced in pathogen-free chickens the specific anti-IBDV antibodies at titers comparable to those induced by a commercial vaccine. Moreover, all the immunized birds survived the challenge with a highly virulent IBDV strain, without major histomorphological alterations of the bursa of Fabricius, similar to what was achieved with the commercial inactivated vaccine (Marusic et al. 2021).
Potential application of probiotics in mycotoxicosis reduction in mammals and poultry
Published in Critical Reviews in Toxicology, 2022
Alaleh Zoghi, Svetoslav Dimitrov Todorov, Kianoush Khosravi-Darani
Śliżewska et al. (2016) assessed the toxicity (genotoxicity and cytotoxicity) of the fecal water of chickens exposed to OTA-contaminated feed in presence of multi-strain probiotic preparation (L. paracasei LOCK 0920, L. brevis LOCK 0944, L. brevis LOCK 0945, and S. cerevisiae). The mentioned study was conducted with 20 healthy female Ross broiler chickens and separated it into 4 experimental groups. Fecal water samples were collected from the experimental birds on the 35th day. Results were confirming the beneficial role of the applied probiotic preparation and a decrease in the extent of DNA damage to 4.74 ± 0.78 were observed. In birds supplemented with the probiotic preparation, the genotoxicity and cytotoxicity were statistically significantly decreased. El-Kerdasy et al. (2019) studied the effect of probiotics as feed additives on chickens (Eighty-one-day old Hubbard chicks) fed an ochratoxicated ration (2.5 mg/1 kg). According to their results, supplementation with probiotics in the ochratoxicated ration positively improved not only the total body weight but as well the organ weight in comparison with the ochratoxicated ration only, which showed an increase in the relative weight of livers and kidneys. On the other hand, there was a decrease in the relative weights of the bursa of Fabricius and the spleen (El-Kerdasy et al. 2019).
An extensive review of experimental ochratoxicosis in poultry: II. Hemato-biochemical and immunological alterations along with other health issues
Published in Toxin Reviews, 2021
OTA also causes immunosuppressive effects in bursa of Fabricius, spleen and thymus (Chang and Hamilton 1980, Bennett and Klich 2003, Khatoon et al.2017, Bhatti et al.2017, 2018, Khatoon et al.2018). OTA suppresses both humoral and cell mediated immune responses in birds (Stoev et al.2000). OTA indirectly suppresses cell mediated immunity (CMI) as it causes thymus depletion and reduction in T-lymphocytic count leading to delayed hyper-sensitivity response in birds (Dwivedi and Burns 1985, Singh et al.1990). OTA also significantly reduces humoral immune response in birds as diagnosed by little to no HA titers against sheep red blood cells (Verma et al.2004). It also causes a decrease in immunoglobulin levels in fowls (Dwivedi and Burns 1984) along with thymic regression in 3 weeks old turkey poults (Chang et al.1981).
Chicken toll-like receptors and their significance in immune response and disease resistance
Published in International Reviews of Immunology, 2019
Aamir Nawab, Lilong An, Jiang Wu, Guanghui Li, Wenchao Liu, Yi Zhao, Qimin Wu, Mei Xiao
ChTLR4 recognizes lipopolysaccharide (LPS), which is a major structural component of gram-negative bacteria outer cell wall and involved in the activation of immune responses. LPS receptors interact with extracellular proteins and make a complex of TLR4 (toll-like receptor 4), CD14 (cluster of differentiation 14) and MD2 (myeloid differentiation protein 2) such as (TLR4 +CD14 +MD2) [12]. ChTLR4 and MD-2 are about 43 and 31% homologous to their respective human orthologs at the protein level. While chCD14 shows 34% protein homology with human CD14 and shares various structural features like conserved LRRs and conserved cysteines [31]. Several cells and tissues including B cells, heterophils and macrophages as well as spleen and bursa of fabricius express chTLR4 [14, 20]. LPS binds to chTLR4 inducing a signaling cascade that activates NF-kB to produce pro-inflammatory cytokines and chemokine’s [32, 33].