The recognition of abnormal forms of HLA-B27 by CD4+ T cells

Louise H Boyle1, Jane C Goodall, J S Hill Gaston

  • 1Cambridge Institute of Medical Research, University of Cambridge School of Clinical Medicine, Department of Medicine, Cambridge, UK. lhb22@cam.ac.uk

The MHC class I molecule, HLA-B27 can be expressed as a number of non-conventional forms, in addition to conventional HLA-B27 heterodimers presenting peptide. This has lead to new avenues of research to explain the association of this molecule with SpA. Surprisingly, HLA-B27 transgenic animal models implicated CD4+ T cells, which conventionally interact with MHC class II molecules, not MHC class I molecules, in the pathogenesis of SpA. One hypothesis to explain these finding is that non-conventional forms of HLA-B27, specifically HLA-B27 homodimers, might mimic MHC class II molecules and be recognised by CD4+ T cells. We investigated whether CD4+ T cells from AS patients can interact with HLA-B27, discovering that indeed CD4+ T cells can interact with various forms of HLA-B27. Here we discuss how such interactions between HLA-B27 and CD4+ T cells could occur in vivo and potential contributions of such interactions to the pathogenesis of SpA.

Related Concept Videos

T Cell Activation and Clonal Selection01:22

T Cell Activation and Clonal Selection

T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...
Antigens Involved in Adaptive Immunity01:26

Antigens Involved in Adaptive Immunity

An antigen is any substance the immune system identifies as foreign and potentially harmful to the body, prompting an immune response. Antigens have two functional properties: immunogenicity and reactivity. Immunogenicity is the ability of an antigen to stimulate a specific immune response. At the same time, reactivity describes the antigen's ability to react with the cells and antibodies produced in response to it.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Cytotoxic T Cells-mediated Immune Response01:27

Cytotoxic T Cells-mediated Immune Response

Cytotoxic T cells are a vital component of the immune system. They have the remarkable ability to identify and target antigens on infected or abnormal cells. These antigens often originate from intracellular pathogens such as viruses or abnormal proteins cancer cells produce.
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
Cell-mediated Immune Responses01:40

Cell-mediated Immune Responses

Overview
Defense Against Bacterial Pathogens01:31

Defense Against Bacterial Pathogens

The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
B Cell Activation and Differentiation01:24

B Cell Activation and Differentiation

The adaptive immune response, a sophisticated defense mechanism, relies on the activation and differentiation of B lymphocytes, or B cells. These processes enable our bodies to mount a tailored response against specific pathogens such as bacteria, free virus particles, toxins, and parasites.
When naive B cells encounter a specific antigen that can bind to the B cell receptor (BCR) on their surface, they undergo sensitization to respond to the antigen's presence. Sensitization begins with...