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Biosensors for Disease Diagnosis
Published in Ayodeji Olalekan Salau, Shruti Jain, Meenakshi Sood, Computational Intelligence and Data Sciences, 2022
Ramneet Kaur, Dibita Mandal, Juveria Ansari, Prachi R. Londhe, Vedika Potdar, Vishakkha Dash
Lentivirus is a genus of retroviruses that cause chronic diseases that have a characteristic long incubation period. Human immunodeficiency virus or HIV is the most commonly known lentivirus, which causes acquired immunodeficiency syndrome (AIDS). HIV known as the immunodeficiency virus suppresses the immune system and affects its ability to combat ordinary diseases such as the common cold. HIV infects type CD4 T helper cells affecting the body’s immune system. Around 38 million people were predicted to contract HIV in 2019. The death toll reached 69,000, and 1.7 million new cases were found in 2019. Looking at the impact of HIV on public health, scientists all over the world are developing new kits to detect HIV using antibodies. However, great limitations are faced during the detection of HIV at a very early stage of infection. Methods such as the use of metal nanoparticles (NPs) are employed, trying to increase the sensitivity and accuracy of the detection tests. Point-of-care (POC) diagnostic methods are being developed, since they have a very high sensitivity and can be applied in early-stage detection of HIV in children in mother-to-child transmission, antiretroviral therapy, etc., by using nanoscale technologies. Some emerging methods which qualitatively and quantitatively detect HIV are listed below [12].
Immunotherapy and Vaccines
Published in Raj Bawa, János Szebeni, Thomas J. Webster, Gerald F. Audette, Immune Aspects of Biopharmaceuticals and Nanomedicines, 2019
Johanna Poecheim, Gerrit Borchard
Two types of adaptive immune responses are to be distinguished. Humoral immunity is mediated by antibodies, also known as immunoglobulins (Igs), which are produced by B lymphocytes. The most abundant isotypes are IgG, found in blood serum and lymph, and IgA, as the main effector of the mucosal immune system. Ratios of IgG2/IgG1 subclasses >1 are associated with type 1 helper (Th1) responses, whereas any ratio <1 corresponds to type 2 helper (Th2)-biased immune responses. Simultaneously cell-mediated immunity is induced, mediated by T lymphocytes. The main difference between these lymphocyte subtypes is that Ig receptors of B cells bind whole molecules and intact pathogens, whereas T cells recognize only short peptide antigens (Kumar et al., 2012b), the so-called T cell epitopes. At the site of infection APCs internalize, process, and present T cell epitopes by the major histocompatibility complex (MHC or CD1) molecules expressed at the cell surface. These cells subsequently migrate to the draining lymph nodes (LNs), a collection point where APCs interact with naive T cells. The T cell receptor (TCR) recognizes peptide antigens presented at the surface of these immune cells and, thus, activates the T cell (Von Andrian and Mackay, 2000). Antigen structures from intracellular infections are presented by MHC class I molecules and antigens from extracellular pathogens by MHC class II molecules. Depending on these two classes, T cells differentiate into one of two types of effector T cells: T helper cells (CD4+ cells) to fight off extracellular pathogens and cytotoxic T cells (CD8+ cells) to eliminate infected cells. The CD4+ T helper (Th) lymphocytes are commonly divided into Th1 and Th2 subtypes. Th1 cells release pro-inflammatory cytokines to activate macrophages and cytotoxic T lymphocytes (CTLs) that are a part of the cellular immune system. Th2 cells help B cells to maturate to antibody-producing plasma cells, thereby supporting humoral immunity (Fig. 3.1).
Effect of low dose radiation from general X-ray to T-cell lymphocyte expression using an in vitro method
Published in Radiation Effects and Defects in Solids, 2022
Gunjanaporn Tochaikul, Nuttapong Danthanavat, Chalermchai Pilapong, Nutthapong Moonkum
T cells are an essential part of the immune system (18). The CD4+ T helper cells (Th cells), play an important role in the immune system, particularly in the adaptive immune system (19). CD8+ T cells (often called cytotoxic T lymphocytes, or CTLs) are very important for an immune defence against intracellular pathogens, including viruses and bacteria, and tumour surveillance (20). Typically, The CD4/CD8 ratio in the peripheral blood of healthy adults and mice is about 2:1, and an altered ratio can indicate diseases related to immunodeficiency or autoimmunity (21).