Endogenousselfpeptides guard immune privilege of the central nervous system Self peptides are fragments of the body's own proteins that play a critical role in the immune system's ability to distinguish between "self" and "non-self作者：HA Abdelsamed·2021·被引用次数：6—Direct allorecognition involves the binding of self (recipient) TCRs to non-self (donor) MHC molecules loaded withself-peptides, whereas ...." These peptides, presented on the surface of cells via Major Histocompatibility Complex (MHC) molecules, are fundamental to T cell development and function. While generally ensuring immune tolerance, a dysregulated recognition of self-peptides can unfortunately lead to autoimmune diseases. Understanding the intricate world of self peptides is crucial for comprehending immune surveillance, transplantation tolerance, and the pathogenesis of various immune-mediated conditions.
During the development of T cells in the thymus, exposure to a diverse repertoire of self peptides presented on MHC molecules is essential for shaping their reactivity. This process, known as thymic selection, involves two key stages: positive and negative selection.
* Positive Selection: Developing T cells that can weakly recognize self-peptide/MHC complexes are positively selected, meaning they survive and mature. This ensures that T cells are capable of interacting with the body's own MHC molecules, a prerequisite for recognizing foreign antigens presented by them. The self-peptide repertoire critically influences which T cells are positively selected, thereby defining the T cell receptor repertoire that will patrol the body作者：MW Kim·2025·被引用次数：41—We demonstrate that the CNS presentsselect endogenous self-peptides on MHC-II moleculesto communicate with and dampen autoreactive T cell responses..
* Negative Selection: T cells that bind too strongly to self-peptide/MHC complexes are eliminated through negative selection. This crucial step prevents the immune system from mounting an attack against the body's own tissues, thereby maintaining self-tolerance.
While the primary function of self peptides is to promote tolerance, their aberrant presentation or recognition can have detrimental consequences. When the immune system mistakenly identifies self peptides as foreign, it can mount an autoimmune response.作者：MW Kim·2025·被引用次数：41—We demonstrate that the CNS presentsselect endogenous self-peptides on MHC-II moleculesto communicate with and dampen autoreactive T cell responses. This occurs when T cells that should have been deleted during negative selection become activated, leading to the attack of healthy tissues.作者：GM Barton·2002·被引用次数：29—Our results suggest that individual peptide–MHC complexes positively select different subsets ofself-MHC-reactive T cells.
Several factors can contribute to immunogenic self-peptides causing autoimmune disease. These include genetic predispositions, environmental triggers like infections, and alterations in the normal processing or presentation of self peptides. For instance, certain self peptides, such as the self-peptide MART1(27-35) derived from the Melan A/MART1 protein, can become targets for CD8+ T cells in conditions like melanoma. The recognition of self-peptide/MHC complexes by autoreactive T cells is a hallmark of many autoimmune disorders, including type 1 diabetes, rheumatoid arthritis, and multiple sclerosis.
The significance of self peptides extends beyond immune tolerance. Research has unveiled novel roles for these endogenous fragments in various physiological and pathological processes.
* Immune Privilege: Endogenous self-peptides presented on MHC-II molecules can help maintain the immune privilege of certain tissues, such as the central nervous system (CNS). By communicating with and dampening autoreactive T cell responses, they contribute to protecting these vital areas from immune attack作者：JC Prinz·2023·被引用次数：23—The objective of this article is to highlight important aspects to be considered in the discovery ofimmunogenic self-peptidesin autoimmune diseases..
* Nanoparticle Delivery: Interestingly, self peptides have demonstrated a capability to delay macrophage-mediated clearance of nanoparticles. This property can be harnessed to promote persistent circulation of nanoparticles, thereby enhancing their delivery to target sites, including tumors. This opens up new avenues for drug and dye delivery systems.
* Transplant Tolerance: The self-peptide repertoire also plays a critical role in transplant tolerance inductionIn positive selection of T-cell development, thymocytes that bindself-peptide MHC are positively selectedand survive whereas in negative selection, those .... Understanding how self-peptides influence immune responses to transplanted organs could lead to strategies for preventing rejection and improving transplant outcomesDefining the Role of T Cell Receptor - Self-Peptide/MHC Class ....
The study of self peptides is a dynamic and evolving field. Researchers are continuously exploring new techniques to identify and characterize self peptides involved in health and disease. Advances in mass spectrometry and computational biology are aiding in the discovery of novel self peptides and their interactions with MHC molecules.
The ultimate goal is to leverage this knowledge for therapeutic interventions. By understanding how self peptides shape immune responses, scientists aim to develop strategies to prevent or treat autoimmune diseases, enhance the efficacy of immunotherapies, and improve the success of organ transplantation. The intricate dialogue mediated by self peptides within the immune system holds immense potential for future medical breakthroughs.
Join the newsletter to receive news, updates, new products and freebies in your inbox.