The major histocompatibility complex (MHC) is responsible for binding peptide fragments arising from pathogens in order to display them on the cell surface for recognition from immune cells. Once recognized, the foreign pathogen is typically evaded. The MHC complex is broken into two categories, MHC Class I proteins and MHC Class II proteins. MHC complex I and II proteins are all very different and contain specific molecules to bind different peptides – in fact, they have been described as the most polymorphic genes there are.
Integrins are transmembrane receptors composed of alpha and beta chains, where beta-integrins are mainly expressed in leukocytes. Leukocytes are white blood cells that act in the immune system to defend our body against foreign pathogens.
NFkB is a transcription factor that plays a role in the expression of genes involved in immune response, inflammation, metastasis, cell survival and more. RelA (p65) is one member of the NFkB mammalian family, alongside other subunits.
Exosomes are spherical to cup-shaped bilayered membrane enclosed nanosize vesicles (30-100 nm) which have the ability to shuttle active cargoes between cells. Johnstone et al. 1987 pioneered in documenting the generation of exosomes in differentiating reticulocytes as a result of the fusion of multi-vesicular endosomes/MVBs with the plasma membrane.
TRIF, also known as toll like receptor adaptor molecule 1 or TICAM1, is known for its role in invading foreign pathogens as part of our innate immune response. TRIF/TICAM1 is a TIR-domain adaptor protein (toll/interleukin-1 receptor) that interacts with the Toll-like receptors (TLRs) through intracellular signaling and recognition of its TIR site.
MHC molecules (also known as major histocompatibility complex molecules) assist in the presentation of antigens to T cells in order to eradicate foreign pathogens. These molecules are highly polymorphic, meaning that they exist in multiple variants in order to avoid pathogens evading their activation of the immune response. MHC Class I molecules in particular deliver cytosolic peptides to the cell surface so that they can continue on through the cytosol and ultimately the endoplasmic reticulum (ER).
CD4+ T-helper cells (Th) are the white blood lymphocytes expressing surface glycoprotein antigen CD4. These T-helper cells play an important role in the adaptive immune system by releasing T cell cytokines that help other immune cells to suppress or regulate immune responses. CD4+ T-helper lymphocytes can be divided into two types (Th1 and Th2) based on their cytokine secretion. Th1 cells are involved in cell-mediated immune response to intracellular pathogens and delayed-type hypersensitivity reactions.
Our immune system is a powerful defense mechanism against infection, however different variables can cause our immune response to work for or against us. CD3 (cluster of differentiation 3) is one component of our immune signal response that is composed of four distinct chains (CD3-g, CD3-e, CD3-s and the zeta chain). These chains associate with a molecule known as the T-cell receptor (TCR) to comprise the TCR complex.
Is has been established that the regulatory transcription factor FOXP3 (a member of the forkhead/winged-helix family of transcription factors) is imperative to immune system homeostasis through CD4+CD25+ regulatory T cell function. Distinctively, FOXP3 binds to specific regions of DNA to modulate the activity of genes that are involved in regulating the immune system. Interruption of FOXP3 activity leads to autoimmune disorder, due to Treg cells not having their full ability to act as an immune system balancer.
Toll like receptors (TLRs) are highly conserved proteins that are first known for their role in pathogen recognition and immune response activation. In order to elicit the necessary immune response in reaction to a foreign pathogen, TLRs trigger cytokine production depending on the behavior patterns of the pathogen itself. Specifically, TLR4 acts through bacterial lipopolysaccharide (LPS), which composes the outer wall of Gram-negative bacteria. Bacterial LPS is also a potent activator of the immune system.
