Selective killing of hepatitis B envelope antigen-specific B cells, by class I-restricted, exogenous antigen-specific T lymphocytes
Article Abstract:
An antigen is a substance perceived by the body as foreign, which stimulates the formation of antibodies. Antigen must be presented to T helper lymphocytes, usually by a cell in the immune system known as the macrophage, as a step in the activation cascade for an immune response to occur. B cells, a type of lymphocytes, can also present antigen. B cells contain immunoglobulin molecules on their cell surface, which bind antigens. The antigens generally combine with the class II molecules of the major histocompatibility complex (MHC) and then are presented to T lymphocytes. Antigens and noninfectious viral particles have been shown to associate with class II MHC molecules. There are only a few reports of such molecules associating with class I MHC molecules. One of these molecules is the envelope antigen of the hepatitis B virus. It was shown that B cells can present the hepatitis B envelope antigen to cytotoxic T cells, which can recognize antigen only in association with class I molecules. The cytotoxic T cells then kill the B cells which presented the antigen. B cells normally elicit an antibody response. Therefore, this may be a mechanism by which the antibody response against the hepatitis B virus is suppressed. This suppression of the antibody response is seen in individuals who are chronically infected with hepatitis B virus and are carriers of the hepatitis B virus. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1990
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Activated CD8 binding to class I protein mediated by the T-cell receptor results in signalling
Article Abstract:
For an immune response to occur, antigens must be in a complex with the major histocompatibility antigens to be recognized by the T cell receptor on T lymphocytes. The CD8 molecule on a subset of T lymphocytes, known as cytotoxic T cells, which kill foreign cells, also binds to the major histocompatibility complex proteins of the class I type. This interaction allows antigens to be recognized and T cells to be activated. The CD8 molecule binds to the histocompatibility antigens only if antigens are present. This indicates that the binding of CD8 to the histocompatibility antigen is activated by the T cell receptor, which binds antigens. This was shown to be true using antibodies that are specific to the T cell receptor, which act as antigens do, by binding to the T cell receptor. The binding of the antibody to the T cell receptor activates the binding of the cytotoxic T cells to class I histocompatibility molecules. This binding is blocked with antibodies to the CD8 molecule, indicating that the binding occurs by this molecule. This study furthers the understanding of the molecules and the interactions which occur in a immune response. As the mechanisms of the immune response are understood, it is hoped that they can be manipulated so that immune responses can be made to otherwise unrecognized proteins on cells that are involved in causing disease. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1990
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Dendritic cells capable of stimulating T cells in germinal centres
Article Abstract:
The CD4+CD11c+CD3- dendritic cells are capable of stimulating the T cells in germinal centres. These cells help the processes involved in the generation of memory B cells within the lymphoid organ germinal centres. These dendritic cells are strong antigen-presenting cells for T cells. However, they fail to activate the CD40-stimulated B cells. Two types of antigen-presenting cells are found in the human germinal centres. The follicular dendritic cells stimulate the B cells, while the dendritic cells stimulate the T cells.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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