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How do CD8 T cells kill infected cells in the immune response process?
CD8 T cells kill infected cells by releasing proteins called perforins and granzymes. Perforins create pores in the infected cell's membrane, allowing granzymes to enter and trigger cell death. This process helps eliminate the infected cell and stop the spread of the infection.
Are cytotoxic T cells a type of T cell clone?
Yes, cytotoxic T-cells are a subset of T-cells that in contrast to helpter T-cells express CD8.
What is the function of the cytotoxic T cells?
Cytotoxic T cell's primary responsibility is to kill infected cells. I'll start from the beginning. From a progenitor cell in the bone marrow, the T cell will begin maturation in the thymus. In the thymus it begins in the cortex as a pro T cell. In this stage it is considered a double negative cell (I'll explain more later). Here it has the beta chain (V,D,J's) rearranged. Next it becomes a pre T cell. By now the T cell has finished rearranging its beta chain and now begins rearrangement of its alpha chain. Both the beta and alpha chain under go allelic exclusion. This prevents one of the alleles from being expressed (this would be mom's or dad's). If the pro T cell made a beta chain from your mothers allele, your father's allele would be suppressed. This is an important feature, otherwise you could accidentally make a stop codon and that would stop your T cell development right there. So as a pre T cell it continues to proliferate and it upregulates CD3, CD4 and CD8. You have two types of T cells that it can mature to. CD4 and CD8. A CD4 T cell is also known as a helper T cell and a CD8 T cell is also called a cytotoxic T cell. They function very differently but at this point the T cell doesn't know which one it will become. Therefore it is at this juncture a double positive thymocyte. The next phase is an immature T cell. Here the alpha chains have finished rearrangement (also allelic exclusion applies here). Now the cell will undergo positive and negative selection. The immature T cell is tested by thymic epithelial cells (TEC). TEC's have a unique feature that belongs to professional antigen presenting cells (APC's) and that is expressing both MHC class I and MHC class II on its cell surface. An immature T cell that can bind to a TEC's MHC class I or MHC class II is positively selected to continue maturation. This is an important step because ensures that your T cells are specific for your body's MHCs. However, if the immature sticks too strongly, it will be neglected and eventually die. You don't want a mature T cell that binds way too strongly on your own cells either. Those that don't bind at all will also die by neglect. The strict standards ends up killing about 95% of all maturing T cells. The immature T cell that was capable of binding to MHC class I molecule is signaled to become a CD8 or cytotoxic cell and the immature T cell that was capable of binding to MHC class II molecule is signaled to become a CD4 or helper T cell. Now that your immature T cells have been primed to your own body, it will undergo negative selection. In this process it is exposed to other types of cells, dendritic cells and macrophages. Dendritic cells and macrophages are part of your APCs. If the T cell binds too strongly it will also die by neglect. Congratulations! Your immature T cell is now a mature naive T cell. It is now ready to leave your thymus and it will be stored mainly in your lymph nodes to await an infection. Now that your cytotoxic T (CD8) cell has been made, it waits in your lymph node for an infection. A dendritic cell (remember these guys? they are present all over your body) will come in through an afferent lymphatic vessel from the source of infection. An important feature of cytotoxic T cells is that it targets cytoplasmic infection, or more specifically viruses. Generally viruses proliferate within a cell and antibodies cannot get to them if the virus is residing inside one of your own cells. So the dendritic cell gets infected and travels through the afferent lymphatic vessel into your lymph nodes. Here waits all of your adaptive immunity responses. It's an ambush! Your cytotoxic cells have been waiting for this moment. The cytotoxic cell that is specific for the antigen that is presented on the dendritic cell latches on. There are two signals that activate the cytotoxic (CD8) cell. B7 from the dendritic cell attaches to CD28 on the cytotoxic T cell and CD8 attaches to the dendritic cell. The cytotoxic cell is now activated and it is now on a mission to destroy. It secretes IL-2 which binds to itself. This is an autocrine function that signals the cytotoxic cell to replicate like crazy. Your army travels out through the efferent lymphatic vessel into your blood stream. Eventually it arrives to the cells that are infected. It is capable of binding to the same antigens that it first recognized from the dendritic cell that brought it inside initially. It latches on with CD8 and releases its' weapons. Perforin is released which punches holes into the cell and granzymes are also released which induces apoptosis (cell death). Memory T cells are also made to fight against future infection. These are long lasting cells. Your other T cells (remember them?) the helper T cells come by and deactivate your cytotoxic T cells with FasR and CTLA-4. Hope that helps.
What cells engulf antigens and present fragments of them on their own surfaces where they can be recognized by cells that will deal with them?
Antigen-presenting cells, such as dendritic cells, macrophages, and B cells, engulf antigens and present fragments of them on their cell surfaces. These antigens are then recognized by T cells, particularly CD4+ helper T cells or CD8+ cytotoxic T cells, which play a key role in initiating an immune response against the antigen.
What is the role of T cells in a human body?
T cells are part of the adaptive immunity. There are two major types of T cells: CD4+ T helper cells and CD8+ T cytotoxic cells. T helper cells primarily function in humoral immunity whereas T cytotoxic cells are important in cell mediated immunity. T helper cells produce cytokines to activate other immune system components like macrophages, B cells, etc. whereas T cytotoxic cells primarily kill infected cells.
The most important cell in neoplastic cell clearance is natural killer cell or cd8 plus th cell?
Both the natural killer cell and the cd8 plus the cell are the most important cell in neoplastic cell.
How do CD8 T cells kill infected cells in the immune response process?
CD8 T cells kill infected cells by releasing proteins called perforins and granzymes. Perforins create pores in the infected cell's membrane, allowing granzymes to enter and trigger cell death. This process helps eliminate the infected cell and stop the spread of the infection.
What is the specific blood cell to which HIV is attached is it CXCR4-T or gp120-T or CCR5-T or CD4-T or CD8-T?
CD4+ or T=helper cell.
What is meant CD8 or cytotoxic T cells?
A cytotoxic T-cell is a form of lymphocyte that is the "killer" T-cell. This cell engulfs damaged or viral/bacterial cells to stop them from infecting the blood.
What does abscd8-cd57 equals lymphs mean equals 28?
abs = absolute count. It is the number of that type of cell in a given volume. CD8 identifies suppressor/ cytotoxic lymphocytes. CD57 identifies a type of cell called a natural killer (NK) cell. If they mean CD8 positive and CD57 positive it is the count of NK cells. If they mean CD8 positive and CD 57 negative then it is the count of suppressor T cells (that are not N cells). What 28 means would depend on the units. Sorry to be a bit complicated. Basically, they are counting a specific type of white blood cell.
When an antigen binds to a Class 1 MHC molecule it stimulates what cell?
Class I MHC molecules present antigens to cytotoxic T-cells (which are CD3+CD8+).
What are Db-gp33-specific CD8 T cells?
Db-gp33-specific CD8 T cells are cytotoxic CD8 T-cells which can specifically recognize the gp33 epitope when presented in the context of the mouse MHC class I complex, H-2Db. The gp33 epitope is comprised of the sequence of amino acids in positions 33-41 of the glycoprotein from LCMV (Lymphocytic Choriomeningitis Virus).
Which cell produces perforin?
Perforin is produced by cytotoxic T cells (CD8+ T cells) and natural killer (NK) cells. It is used in these cells to induce cell apoptosis in target cells, such as infected or cancerous cells.
Why only cd4 ceels are damaged in hiv n cd8 remain safe?
coz CD8 and CD4 are two diffrent types of proteins .. n HIV requires cd4 to fuse for replicatin
How are cytotoxic T lymphocytes produced?
CD8+ T cells divide and differentiate into cytotoxic T lymphocytes.
What are the cells called in your immune system that kill virus?
By mean of 2 cells One belong to innate immune system are natural killer cell(NK) the other belong to adaptive immune system are CD8+ cytotoxic T cells I heard it's white cell who kills the virus! white cell is bigger than normal cell and it's limited in amount. Every white cell will die after they kills virus.that why the liquid filled in the pox is white.
What is a extracellular bacteria?
Intracellular Bacteria is bacteria that lives inside of a cell such as a macrophage. If the cell knows the bacteria is living inside of it the cell will destroy it, but some times bacteria can not be detected by the cell, so it lives inside of the cell. But how does the body destroy intracellular bacteria? In order for the cell to destroy the intracellular bacteria it needs the assistance of a T-Cell. OK, lets put the cell that contains the intracellular bacteria aside for right now. The T-Cell has previously found a different cell that recognized the virus and destroyed the virus. After the cell destroyed the virus it placed a piece of the virus along with a piece of MHC on the outer wall of itself. The cell is now called a "Presenting Cell". A T-Cell comes along and binds to the presenting cell recognizes that it killed the bacteria and begins to proliferate (divide) into thousands of CD8+ and CD4+ cells. The new CD4+ cells then differentiate or divided in to TH1 or TH2 cells. NOW... as the TH1 cells are moving around our body. The TH1 cells are very good at recognizing cells such as macrophages that have the intracellular bacteria living inside of it. When the TH1 cell find a cell that contains intracellular bacteria, the TH1 cell attaches itself to the cell that contains the intracellular bacteria and reprograms the cell it so it recognizes the intracellular bacteria and then destroys it. What happens after the TH1 cell reprogrammes the cell that contains the intracellular bacteria? The reprogramming allows the lysosomes inside of the cell to recognize the bacteria. The cell then forms a Phagosome around the intracellular bacteria. lysosomes inside of the cell attach the Phagosome creating a Phagolysosome. The Phagolysosome is like a bag that contains the intracellular bacteria and destroys the bacteria though lysosomal enzymes and other toxins. The cell then releases the destroyed bacteria as debris.
