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Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces , antigen processing must occur before the antigen fragment can be recognized by a T-cell receptor .
It is in this way, the MHC class I-dependent pathway of antigen presentation, that the virus infected cells signal T-cells that abnormal proteins are being produced as a result of infection. The fate of the virus-infected cell is almost always induction of apoptosis through cell-mediated immunity, reducing the risk of infecting neighboring ...
After the processed antigen (peptide) is complexed to the MHC molecule, they both migrate together to the cell membrane, where they are exhibited (elaborated) as a complex that can be recognized by the CD 4+ (T helper cell) – a type of white blood cell. [note 7] [20] This is known as antigen presentation.
The latter case induces recognition by antigen-specific Th2 cells or Tfh cells, leading to activation of the B cell through binding of TCR to the MHC-antigen complex. It is followed by synthesis and presentation of CD40L (CD154) on the Th2 cell, which binds to CD40 on the B cell, thus the Th2 cell can co-stimulate the B cell. [11]
The idiotype is based upon the variable region (labeled VL and VH in the diagram.) In immunology, an idiotype is a shared characteristic between a group of immunoglobulin or T-cell receptor (TCR) molecules based upon the antigen binding specificity and therefore structure of their variable region.
HLA-A projected away from the cell surface and presenting a peptide sequence. The peptide-MHC complex presents a surface that looks like an altered self to the TCR. [11] The surface consisting of two α helices from the MHC and a bound peptide sequence is projected away from the host cell to the T cells, whose TCRs are projected away from the T cells towards the host cells.
Once the exogenous antigen peptide is loaded onto the MHC class I molecule, the complex is exported to the cell surface for antigen cross presentation. There is also evidence that suggest that cross-presentation requires a separate pathway in a proportion of CD8(+) dendritic cells that are able to cross-present.
"An immunologic adjuvant is defined as any substance that acts to accelerate, prolong, or enhance antigen-specific immune responses when used in combination with specific vaccine antigens." [ 2 ] In the early days of vaccine manufacture, significant variations in the efficacy of different batches of the same vaccine were correctly assumed to be ...