Immunity system complexity: T c ell activity (Introduction)

by David Turell , Saturday, April 16, 2022, 20:36 (739 days ago) @ David Turell

There are many types of T cells working alongside B cells:

https://offers.the-scientist.com/hubfs/TS_PPL_Sartorius_T%20Cell_White%20Paper/Understa...

"The human immune system is made up of a complex network of cells that provide continuous surveillance for anything that is non-self, such as bacteria or viruses. There are two main branches—innate and adaptive immunity—that serve different functions but work together to overcome the different challenges the body may face. Innate immune cells are responsible for the initial response, rapidly recognizing the antigen, and generating a proinflammatory response to quickly and efficiently contain it. This includes the recruitment of macrophages, neutrophils, monocytes and dendritic cells, which in turn stimulates cells in the adaptive immunity pathway to multiply and differentiate to overcome the specific infection.This adaptive branch is mainly made up of the thymus-derived lymphocytes (T lymphocytes) and bone-marrow-derived lymphocytes (B lymphocytes), and its roles include the elimination of foreign species, the formation of immunological memory, and ensuring tolerance to self-antigens. Natural killer cells (NK cells) lie in between the two branches, as they possess some qualities of both

"T cells are vital for pathogen elimination and tumor immunosurveillance, and the body is capable of producing an array of specialized T cells that provide unique responses to the diverse spectrum of tumor cells and pathogens (viruses, bacteria, and parasites) that are
capable of penetrating host defenses. Upon elimination of a tumor or pathogen, the majority of adaptive cells die, and memory cells are formed to provide a rapid response should recurrence or reinfection occur. The immune system therefore relies on a fine balance of pathways to regulate immune activation and immune suppression in order to maintain homeostasis. Too much suppression can reduce host tumor immunosurveillance, allowing
oncogenic cells to proliferate uncontrollably, while over-activation of the immune system can lead to autoimmune diseases.

"T cell’ is an overarching term to describe the function of these immune cells, however, there are multiple subtypes with very distinctive roles. Determining the differences and similarities between these cell populations is vital to understand the roles they could play in therapeutics. The two main types of T cells—cytotoxic (TC) and helper (TH)—can be broken down into further subtypes, and there are also additional populations, such as invariant natural killer T (iNKT) cells, and mucosal associated invariant T (MAIT) cells.

"TC cells are programmed to kill infected cells and tumors, while TH cells produce cytokines and chemokines that recruit and activate other immune cell subsets at areas of infection. TH cells can be split into numerous subsets that are specialized for different
effector functions. The main subsets are TH1 (respond to virus and intracellular bacteria), TH2 (parasites), TH17 (extracellular bacteria and fungi), TH9, T follicular helper
cells (TFH), and regulatory T cells (TREG). T cells recognize pathogens by binding with antigen presenting cells (APCs) that process foreign proteins and display antigens complexed with major histocompatibility complexes (MHCs) on their cell surface, where it can
interact with TCRs. The recognition of pathogens by APCs leads to the release of cytokines that cause the genetic differentiation of T cells into specific subsets, allowing them to effectively respond to and eliminate the pathogen. For instance, interferon (IFN)-α/β and
IL-12 cytokines are generated in response to many viruses, and induce the expression of the transcription factor T-bet, causing T cells to differentiate into the TH1 subset."

Comment: Presented to overwhelm. A grand complexity of active T cell types. God offered a dog-eat-dog form of life, but also designed protections. dhw will ask why God chose that approach. As usual I can't know what was on God's mind to make Him choose that design. I accept that is what He supplied for us for His good reasons.