An Introduction to the Immune System and Vaccines
Patricia G. Melloy in 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).
Phylogeny of the mucosal immune system
Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald in Principles of Mucosal Immunology, 2020
In contrast to the conserved nature of the thymus, the primary lymphoid organs in gnathostomes vary between lineages. In cartilaginous fish, hematopoiesis takes place in the epigonal organ, whereas in bony fish it is in the head kidney. The role of the bone marrow as the primary hematopoietic tissue evolved in tetrapods and is found in amphibians, birds, and mammals. In well-known species such as mice and humans, B-cell development occurs primarily in the bone marrow. However, in a few mammals and all birds, the gut-associated lymphoid tissue (GALT) has an essential role in B-cell ontogeny. An extreme example of this is birds in which there is a unique avian GALT, the bursa of Fabricius. In fact, B cells acquired their name from the discovery that bursectomized chicks failed to develop antibody responses. Although, phylogenetically speaking, birds and crocodilians (crocodiles and alligators) are closely related, the latter do not have a bursa, and unfortunately little is known regarding B-cell development or the role of the GALT in this lineage.
Avian coccidiosis: a disturbed host-parasite relationship to be restored
G. F. Wiegertjes, G. Flik in Host-Parasite Interactions, 2004
Most cell differentiation (CD) markers found in mammalian species have been described for chickens as well. B- and T-cell receptors are organized in a comparable way, CD4 and CD8 molecules in association with CD3 complex are present on mature T-cells and on immature thymocytes. Breed et al. (1996) described CD4-CD8 (dim) positive T-cells in the circulation of White Leghorn chickens and hypothesized that these function as memory cells being a CD4 cell with some CD8aa remaining. The organization of the chicken lymphoid system is also not very different from that in mammals, but a few functional characteristics are worth mentioning. The famous segregation of B-cell and T-cell ontogeny and maturation in bursa of Fabricius and the thymus respectively made the chicken initially a very attractive model for the early immunologists. The nomenclature of these cells refers to this.
Immuno-toxicological effects of different sub-lethal doses of thiamethoxam (TMX) in broiler birds
Published in Toxin Reviews, 2019
Shafia Tehseen Gul, Ahrar Khan, Maqbool Ahmad, Hassan Ahmad, Muhammad Kashif Saleemi, Muhammad Noman Naseem, Muhammad Bilal
Relative weight of bursa and thymus remained unchanged in all test groups during 1st week of the trial. Relative weight in all TMX treated groups had dose-related reduction as compared to control group during the rest of the experimental trial. Significantly higher relative weights of spleen were observed in TMX treated groups as compared to control group during the 35th and 42nd day of the experimental trial. It remains unchanged during the earlier days of the trial. These results were consistent with the findings of Kammon et al. (2010). Lymphocyte reduction in the medulla and cortex of bursa of Fabricius and gentle interfollicular fibrosis in IMI treated birds were also reported by Kammon et al. (2010). Immunosuppressive effects of neonicotinoids have been characterized by regression in size of immune organs such as bursa of Fabricius and thymus and also alter the number and the function of immune cells and antibody response.
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].
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).