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The Thoracic Lymphatic System and Lymph Nodes, and the Spread of Tumours within the Lungs, the Tracheobronchial Tree and the Mediastinum.
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
Lymphocytes are the basic cells of the lymphoid system and are of three main types - B, T and Null (i.e. not B or T). B lymphocytes when stimulated by antigens differentiate into plasma-cells which in turn produce antibodies. T lymphocytes are of several types: - (i) T-helper cells which produce cytokines and assist B lymphocytes, macrophages and granulocytes, (ii) T-cytoxic cells which destroy cells infected with viruses and tumour cells, and (iii) T-suppressor cells which turn down an immune response. Null cells destroy cells coated with antibodies. T cells are particularly produced in the thymus. Lymphocytes circulate in the blood, rapidly detect antigens (many are specific to certain antigens) and stimulate the production of more lymphocytes in nodes etc. to cause the immune response.
Immunization
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Michael F. Para, Susan L. Koletar, Carter L. Diggs
The clonal expansion and activation of lymphocytes of the various subsets result in the production of multiple types of effector systems. There may be multiplication of B lymphocytes with production of immunoglobulin directed against the antigenic determinants in the vaccine. The mechanisms of action of antibodies include direct neutralization of toxins (as in control of diphtheria), opsonization of pathogens (as in control of pneumococcal infections), complement-dependent microbial lysis (as in meningococcal infections), neutralization of viral infectivity (as in control of hepatitis B infection), and antibody-dependent cellular toxicity (as in the control of Salmonella typhi infections). Any or all of these effector mechanisms can in theory operate individually or collectively depending on the nature of the pathogen, the stage of the immune response, and other factors. Initial immunization also induces memory cells which promote a rapid secondary immune response at the time of exposure to the pathogen.
Dermal filler complications and management
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
Antibody-mediated immunity is controlled primarily by B lymphocytes. If we are to consider NK cells, phagocytes and T lymphocytes as the front-line soldiers of the immune system, it is pertinent to think of B lymphocytes as the generals who coordinate and amplify the attack itself. When microbes invade our body, the front-line cells race to the site of infection to begin to fight it off, whereas B-lymphocytes remain within lymphoid organs awaiting activation by specific antigens. When antigens reach B-lymphocytes, they are absorbed and processed with the encouragement of nearby T-helper lymphocytes. Once they have absorbed and processed antigens (with co-stimulation from T-helper lymphocytes), B-lymphocytes become active and differentiate into plasma cells and memory B-lymphocytes. Plasma cells secrete millions of antibodies specific to the antigen in question for up to five days after activation after which they die, whereas memory B lymphocytes remain within the red bone marrow where they can differentiate into new plasma cells and memory B lymphocytes should there be another infection from the same pathogen.
Cholangiocarcinoma: what are the most valuable therapeutic targets – cancer-associated fibroblasts, immune cells, or beyond T cells?
Published in Expert Opinion on Therapeutic Targets, 2021
Juan Wang, Emilien Loeuillard, Gregory J. Gores, Sumera I. Ilyas
In contrast to T lymphocytes, the role of B lymphocytes in CCA development and progression is far less clear. B cells have an integral role in humoral immunity via the production of immunoglobulins. Upon antigen recognition, naïve B cells become activated B cells and subsequently differentiate into plasma cells, which are capable of antibody production [86]. There are several subsets of B lymphocytes, including pro-tumor or regulatory B cells that can dampen the antitumor immune response and promote tumorigenesis. In pancreatic ductal adenocarcinoma, IL-35 producing B cells stimulated tumor cell proliferation [87]. This B cell subset was recruited to the tumor by the chemoattractant CXCL-13, and CXCL13 blockade resulted in a decline in this population with reduction of tumor growth [87]. Although these findings imply that B cell–based immunotherapeutic approaches may hold promise, the role of B lymphocytes in CCA has yet to be elucidated.
Immunology of HPV-mediated cervical cancer: current understanding
Published in International Reviews of Immunology, 2021
Babban Jee, Renu Yadav, Sangeeta Pankaj, Shivendra Kumar Shahi
B lymphocytes are universally known for their ability to produce antibodies in addition to presenting antigen to T cells and secreting cytokines. These cells can develop immunoregulatory properties during infection [155] and autoimmune disorders [156]. Available evidences indicate that B cells may also play immunoregulatory role in cancer [157]. However, precise role of B cells in tumor immunity, particularly in HPV-mediated cervical cancer, remains unclear. Using a TC-1 mouse model of HPV-induced cervical cancer, Tang et al. have demonstrated that B cells promote tumor progression and contribute in establishing the tumor favoring microenvironment [158]. This study also suggests that targeting of B cells may be beneficial in improving vaccines efficacy in patients. In contrast, Kim and coworkers recently found that B cells promote overall survival of patients suffering with HPV -associated cancers including cervical cancer and activated with the radiotherapy and PD-1 blockade [159]. Further, in a another patients based study, it was shown that B reg cells, a subset of B cells, are elevated in HPV related cervical cancer and have strong association with tumor progression and metastasis. B cells have also found to impair function of CD8+ T cells [160].
COVID-19: captures iron and generates reactive oxygen species to damage the human immune system
Published in Autoimmunity, 2021
B lymphocytes differentiates into long-lived antibody-forming cells and memory B cells that produce antibodies [83]. Differentiation process of B cells is divided into five stages: pre-B cells, immature B cells, mature B cells, activated B cells and plasma cells. The differentiation of pre-B cells and immature B cells is an antigen-independent process that takes place in the bone marrow. Meanwhile, during the antigen-dependent stage, mature B cells are stimulated by antigens and continuously differentiate into plasma cells that synthesise and secrete antibodies. The differentiation at this stage is mainly carried out in the peripheral immune organs. The differentiation of most memory B cells depends on the germinal centres of lymph nodes. Abnormal regulation of spontaneous centres (Spt-GCs) is thought to promote mutations of antibody secreting cells and autoimmune diseases [84]. Although it has been reported that the SARS-COV-2 virus has been found in lymph nodes, the existing evidence still does not strongly support the virus infecting lymphocytes, especially B cells.