Click the button below to see similar posts for other categories

What Are the Mechanisms Through Which T Cells Eliminate Infected Cells?

T cells are super important for our immune system. They help our bodies recognize and get rid of cells that are infected with viruses or bacteria. T cells work mainly in two ways: through cytotoxic T cell (also called CTL) activity, and by releasing special proteins called cytokines.

1. Cytotoxic T Cell (CTL) Activity

Cytotoxic T cells, or CD8+ T cells, are like the assassins of our immune system. They destroy infected cells in a couple of ways:

  • Releasing Cytotoxic Granules: When CD8+ T cells are activated, they let out chemicals called perforin and granzymes. Perforin makes holes in the walls of infected cells, letting granzymes enter. Granzymes then tell the infected cells to commit "cell suicide," a process called apoptosis. About 10-20% of the infected cells can die within hours after CTLs are activated.

  • Fas/Fas Ligand Interaction: CD8+ T cells also use another method called the Fas pathway. When they add a special protein called Fas ligand (FasL), it connects to the Fas receptor on the infected cell. This connection triggers apoptosis, helping to destroy virus-infected cells and cancer cells.

2. Cytokine Secretion

Besides killing infected cells directly, CD8+ T cells also release various cytokines. These proteins help boost our immune response:

  • Interferon-gamma (IFN-γ): This cytokine fights off viruses and helps other immune cells, like macrophages, to eat and destroy germs better. It also makes a protein called MHC more visible, which allows other immune cells to recognize and fight pathogens much more effectively.

  • Tumor Necrosis Factor (TNF): TNF can also make infected cells die and help activate other immune cells, like macrophages. Studies have shown that TNF boosts the power of T cells in killing infected cells.

Statistics and Prevalence

Research shows that CD8+ T cells respond quickly when there’s an infection. During an infection, as much as 50% of the total CD8+ T cells can be specific to the virus or bacteria. A strong T cell response can remove a lot of the infection, with over 90% of infected cells being cleared within a few days after the CTL kicks in.

For viral infections, it’s estimated that more than 70% of getting rid of the virus is due to CD8+ T cells. This shows how crucial they are for our immune defense. Understanding how T cells work is very important for developing treatments and vaccines against infectious diseases.

Related articles

Similar Categories
Bacteriology for Medical MicrobiologyVirology for Medical MicrobiologyImmunology for Medical Microbiology
Click HERE to see similar posts for other categories

What Are the Mechanisms Through Which T Cells Eliminate Infected Cells?

T cells are super important for our immune system. They help our bodies recognize and get rid of cells that are infected with viruses or bacteria. T cells work mainly in two ways: through cytotoxic T cell (also called CTL) activity, and by releasing special proteins called cytokines.

1. Cytotoxic T Cell (CTL) Activity

Cytotoxic T cells, or CD8+ T cells, are like the assassins of our immune system. They destroy infected cells in a couple of ways:

  • Releasing Cytotoxic Granules: When CD8+ T cells are activated, they let out chemicals called perforin and granzymes. Perforin makes holes in the walls of infected cells, letting granzymes enter. Granzymes then tell the infected cells to commit "cell suicide," a process called apoptosis. About 10-20% of the infected cells can die within hours after CTLs are activated.

  • Fas/Fas Ligand Interaction: CD8+ T cells also use another method called the Fas pathway. When they add a special protein called Fas ligand (FasL), it connects to the Fas receptor on the infected cell. This connection triggers apoptosis, helping to destroy virus-infected cells and cancer cells.

2. Cytokine Secretion

Besides killing infected cells directly, CD8+ T cells also release various cytokines. These proteins help boost our immune response:

  • Interferon-gamma (IFN-γ): This cytokine fights off viruses and helps other immune cells, like macrophages, to eat and destroy germs better. It also makes a protein called MHC more visible, which allows other immune cells to recognize and fight pathogens much more effectively.

  • Tumor Necrosis Factor (TNF): TNF can also make infected cells die and help activate other immune cells, like macrophages. Studies have shown that TNF boosts the power of T cells in killing infected cells.

Statistics and Prevalence

Research shows that CD8+ T cells respond quickly when there’s an infection. During an infection, as much as 50% of the total CD8+ T cells can be specific to the virus or bacteria. A strong T cell response can remove a lot of the infection, with over 90% of infected cells being cleared within a few days after the CTL kicks in.

For viral infections, it’s estimated that more than 70% of getting rid of the virus is due to CD8+ T cells. This shows how crucial they are for our immune defense. Understanding how T cells work is very important for developing treatments and vaccines against infectious diseases.

Related articles