Table of Contents
How does allorecognition work?
Allorecognition is the ability of an individual organism to distinguish its own tissues from those of another. It manifests itself in the recognition of antigens expressed on the surface of cells of non-self origin. Allorecognition has been described in nearly all multicellular phyla.
What does Allorecognition mean?
Allorecognition refers to the ability of an individual organism to distinguish its own cells and tissues from those of another from the same species.
What is allogeneic MHC?
Abstract. Direct allorecognition is the process by which donor-derived major histocompatibility complex (MHC)-peptide complexes, typically presented by donor-derived ‘passenger’ dendritic cells, are recognised directly by recipient T cells.
What is allogenic reaction?
Allogeneic responses are potent immune responses that cause allograft rejection. They are characteristically polyclonal, involving many TCR specificities, and are brought about by the activation of both naïve and preexisting, cross-reactive memory T cells.
Why are T cells Alloreactive?
The prevailing explanation for alloreactivity is still that the response of allogeneic T cells to complexes of peptide and MHC (pMHC) is less peptide specific than is conventional (immune) T cell recognition of foreign pMHC complexes and that this so-called ‘degenerate’ response explains the high frequency of …
What is an autoreactive T cell?
Autoreactive T lymphocytes are key players in autoimmune diseases. They can act both as regulatory and effector cells. Various animal models have been used to show that the transfer of autoreactive T cells is sufficient to induce a model of an autoimmune disease.
Why are T cells called MHC?
These peptides, also known as antigens, can derive from pathogens such as viruses or intracellular bacteria. Foreign peptides are brought to the surface of the cell and presented to T cells by proteins called the major histocompatibility complex (MHC).
Why are T cells MHC restricted?
MHC restriction means that different T cells are restricted to either Class I or Class II MHC antigens (Figure 2-6). Cytotoxic T cells are restricted to Class I antigens present on nucleated body cells, thus play a role in protecting against virus-infected cells or cancerous cells.
What is allogeneic T cell?
Allogeneic (“off-the-shelf”) CAR T cells generation and sources of T cells. Allogeneic T cells can be obtained from peripheral blood mononuclear cells from healthy donors, umbilical cord blood or derived from induced pluripotent stem cells (iPSCs).
What are the pathways of T cell allorecognition?
Pathways of T cell allorecognition. (A) In direct pathway allorecognition, MHC Class II and Class I alloantigen is recognised as intact protein on the surface of donor antigen presenting cells (APC) by CD4 and CD8 T cells respectively.
How do T cells recognize alloantigens?
Alloantigen recognition is the mechanism by which T cells may recognize alloantigens and lead to transplant rejection after an organ transplant. It is broadly divided into direct and indirect alloantigen recognition. Donor tissue dendritic cells migrate to lymph nodes, stimulating a measurable percentage of recipient T cells.
What is a a T cell?
A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface .
What is alloantigen recognition?
Alloantigen recognition is the mechanism by which T cells may recognize alloantigens and lead to transplant rejection after an organ transplant. It is broadly divided into direct and indirect alloantigen recognition.