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BioFlix: Adaptive Defenses: T cells and Cellular Immunity

by Pearson
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But what about the rhinoviruses that are already inside our patients cells? Another type of adaptive defence cell called a cytotoxic T-cell can locate and destroy rhinovirus infected cells it provides cell mediated or cellular immunity Let's return to our patients lymph node to see how cytotoxic T-cells become activated The T-cell receptor, or TCR of this particular cytotoxic T-cell is genetically programmed to recognize the rhinovirus epitope when presented by the dentritic cell This time, the epitope is presented differently with an MHC1 which is recognize by a CD8 glycoprotein on the cytotoxic T-cell With the help of cytokines from a nearby helper T-cell the cytotoxic T-cell is activated and clonal expansion occurs resulting in some long lasting memory cells ready for a subsequent exposure and many active cytotoxic T-cells, or CTL's that leave the patients lymph vessel to search for infected cells that present rhinovirus epitope with their MHC1 The epitope is recognized by the TCR of the cytotoxic T-cell and the MHC1 is recognized by the T-cells CD8 glycoprotein The cytotoxic T-cell then secretes perforine molecules which for channels in the infected cells membrane Granzyme, also from the T-cell passes through the perforin channels and activates enzymes that lead to apoptosis the programmed death of the infected cell The cytotoxic T-cell then moves on to look for another infected cell
But what about the rhinoviruses that are already inside our patients cells? Another type of adaptive defence cell called a cytotoxic T-cell can locate and destroy rhinovirus infected cells it provides cell mediated or cellular immunity Let's return to our patients lymph node to see how cytotoxic T-cells become activated The T-cell receptor, or TCR of this particular cytotoxic T-cell is genetically programmed to recognize the rhinovirus epitope when presented by the dentritic cell This time, the epitope is presented differently with an MHC1 which is recognize by a CD8 glycoprotein on the cytotoxic T-cell With the help of cytokines from a nearby helper T-cell the cytotoxic T-cell is activated and clonal expansion occurs resulting in some long lasting memory cells ready for a subsequent exposure and many active cytotoxic T-cells, or CTL's that leave the patients lymph vessel to search for infected cells that present rhinovirus epitope with their MHC1 The epitope is recognized by the TCR of the cytotoxic T-cell and the MHC1 is recognized by the T-cells CD8 glycoprotein The cytotoxic T-cell then secretes perforine molecules which for channels in the infected cells membrane Granzyme, also from the T-cell passes through the perforin channels and activates enzymes that lead to apoptosis the programmed death of the infected cell The cytotoxic T-cell then moves on to look for another infected cell