BAGAIMANA RESPON IMUNITAS SELULER?

Summary

This video explains the concept of cellular immunity, focusing on how the immune system responds to infections and cancer. It covers the activation of T-cells by antigen-presenting cells (APCs), the role of helper T-cells in activating B-cells and cytotoxic T-cells, and the function of cytotoxic T-cells in eliminating infected or cancerous cells. The video also discusses the importance of antigen presentation and how the immune system targets intracellular pathogens. Finally, it touches upon the concept of humoral immunity and encourages viewers to further explore immunology topics.

Takeaways

• 😀 Cells in the body perform specific functions to maintain overall health, but cancerous or infected cells can cause serious damage to tissues and organs.
• 😀 This video focuses on specific immunity and the concept of cellular immune responses.
• 😀 The term 'cellular immunity' is introduced to explain immune responses mediated by cells.
• 😀 T cells play a crucial role in cellular immunity, requiring activation by other immune cells.
• 😀 Antigen presentation is the first step in activating immune cells, involving dendritic cells, macrophages, or B cells that patrol and capture antigens.
• 😀 After capturing the antigen, antigen-presenting cells display antigen fragments on their surface using MHC class 2 molecules.
• 😀 The T cell receptor (TCR) on helper T cells binds to the antigen fragments on MHC class 2 molecules, and this triggers immune responses.
• 😀 Activated helper T cells secrete cytokines (like interleukins) to stimulate other immune cells like B cells and cytotoxic T cells.
• 😀 Cytotoxic T cells, once activated, can attack and kill cancerous or virus-infected cells by inducing apoptosis (programmed cell death).
• 😀 Cytotoxic T cells target cells with MHC class 1 molecules that display antigen epitopes, using the CD8 protein for binding.
• 😀 The process of cellular immunity plays a key role in fighting infections, including viruses like coronavirus, by stimulating T cell responses against infected cells.

Q & A

What are the primary functions of normal cells in the human body?

Normal cells in the human body perform specific functions to support the survival and proper functioning of the body. Each cell type is specialized to contribute to the overall health and maintenance of tissues and organs.

How does cancer or infected cells affect the body?

Cancer or infected cells can damage healthy cells, tissues, and organs. This damage leads to serious health disturbances and may result in various diseases, including cancer and viral infections.

What is the role of cellular immunity in the body?

Cellular immunity is part of the body's immune response that involves specific immune cells, such as T-cells, to target and eliminate infected or cancerous cells, ensuring that the body defends itself against harmful pathogens and abnormal cells.

What is antigen presentation and how does it activate T-cells?

Antigen presentation is the process where antigen-presenting cells (APCs), like dendritic cells, macrophages, and B cells, capture and process antigens. These cells then present fragments of the antigens, called epitopes, on their surface using MHC class II molecules, which activate T-helper cells (CD4+ T-cells).

How do T-helper cells contribute to cellular immunity?

T-helper cells, once activated, secrete cytokines like Interleukin-1 to activate other immune cells, including B cells and cytotoxic T-cells. This activation enhances the immune response to infected or abnormal cells.

What is the role of cytotoxic T-cells in the immune response?

Cytotoxic T-cells (CD8+ T-cells) are responsible for identifying and attacking infected or cancerous cells. They bind to MHC class I molecules presenting antigens on target cells and induce cell death through mechanisms like perforin release and apoptosis.

What is the process by which cytotoxic T-cells destroy infected cells?

Cytotoxic T-cells bind to MHC class I molecules presenting the antigen on the surface of infected or cancerous cells. They release perforin molecules that create pores in the target cell's membrane, allowing granzymes to enter, triggering apoptosis, and leading to the destruction of the target cell.

How do T-cells distinguish between infected or cancerous cells and healthy cells?

T-cells can distinguish infected or cancerous cells by recognizing specific antigens (epitopes) presented on MHC molecules. Healthy cells do not display these abnormal antigens, allowing the immune system to target only the diseased or infected cells.

What happens to cytotoxic T-cells after they destroy a target cell?

After destroying a target cell, cytotoxic T-cells detach and move on to find and destroy other infected cells. Their ability to target multiple cells ensures an effective immune response against pathogens or cancer.

How does the immune system respond to COVID-19 according to the video?

When the coronavirus infects a cell, the virus's antigens are presented by antigen-presenting cells (APCs), which activate cytotoxic T-cells. This leads to a cellular immune response targeting the virus-infected cells and helping the body fight off the infection.