Immunity || types of immunity || cellular immunity || humoral immunity || immunity depth of biology

Summary

In this lecture, the instructor provides a detailed explanation of immunity, covering both humoral and cellular immunity. They explain the concept of pathogens, which cause diseases in the body, and introduce immunity as the body's ability to fight against these pathogens. The lecture goes on to differentiate between active and passive immunity, with a focus on how each works in various situations. Additionally, it highlights key distinctions between humoral and cellular immunity, such as the involvement of antibodies, T-helper cells, and the role of CD4 and CD8 cells in cellular immunity. The lecture also touches on immunity in immunodeficient individuals and the importance of understanding these processes in the context of diseases like cancer and infections.

Takeaways

• 😀 Immunity refers to the body's ability to fight off pathogens (disease-causing microorganisms) such as bacteria and viruses.
• 😀 Immunity can be classified into two types: Active Immunity and Passive Immunity. Active Immunity involves the body creating its own antibodies, while Passive Immunity involves receiving antibodies from an external source.
• 😀 Antibodies like IgG, IgA, and IgM are produced by the body to combat pathogens and help the immune system fight infections.
• 😀 Active Immunity occurs when the body fights infections and creates antibodies in response to pathogens, while Passive Immunity provides immediate protection through antibodies administered by a healthcare provider, such as through immunization.
• 😀 The two main types of immunity, Humoral Immunity and Cellular Immunity, differ in their mechanisms of action. Humoral Immunity involves antibodies produced in response to infections, while Cellular Immunity involves immune cells like T-cells attacking infected cells.
• 😀 Humoral Immunity is effective against extracellular pathogens (e.g., bacteria and viruses outside cells), whereas Cellular Immunity is more effective against intracellular pathogens (e.g., viruses and certain bacteria inside cells).
• 😀 Immunity involves a memory function: the immune system can 'remember' pathogens it has encountered before, which enables quicker and stronger responses upon future exposure to the same pathogens.
• 😀 The immune system can be deficient in certain individuals, meaning that both Humoral and Cellular Immunity may not work effectively in people with weakened or compromised immune systems.
• 😀 Both Humoral and Cellular Immunity are part of Active Immunization, where the body actively fights against pathogens and creates antibodies or immune responses.
• 😀 The key difference between Humoral and Cellular Immunity lies in how they combat pathogens. Humoral Immunity involves antibodies attacking pathogens, whereas Cellular Immunity uses immune cells to directly destroy infected cells.

Q & A

What is the definition of immunity as described in the script?

Immunity is the ability of a host (the body) to fight against pathogens, which are disease-causing microorganisms like bacteria or viruses.

What are pathogens and how do they affect the body?

Pathogens are disease-causing microorganisms, such as bacteria and viruses. When they enter the body, they infect it and can cause illness, triggering the immune response.

What is the difference between active and passive immunity?

Active immunity occurs when the body produces its own antibodies in response to an infection or vaccination. Passive immunity is when antibodies are given directly to the body, such as through an injection of immunoglobulin.

What is humoral immunity and how does it function?

Humoral immunity involves the production of antibodies by B-cells in response to pathogens. These antibodies recognize and attack antigens, which are foreign molecules on the pathogen's surface.

What is cellular immunity and how does it differ from humoral immunity?

Cellular immunity involves T-cells, which do not produce antibodies. Instead, T-cells directly recognize and destroy infected cells or pathogens. Unlike humoral immunity, which targets extracellular pathogens, cellular immunity targets intracellular pathogens like viruses.

What is the role of CD4 and CD8 cells in cellular immunity?

CD4 and CD8 cells are types of T-cells that play critical roles in cellular immunity. CD4 cells assist in the immune response by activating other immune cells, while CD8 cells directly kill infected cells.

What does the term 'immunoglobulin' (Ig) refer to, and what types are mentioned?

Immunoglobulins (Ig) are antibodies produced by B-cells to fight pathogens. The types mentioned include IgG, IgA, IgM, IgE, and IgD, each with different functions in the immune response.

How does cellular immunity eliminate cancer cells?

Cellular immunity, through the action of T-cells, can identify and eliminate cancer cells by targeting tumor-specific antigens and destroying the cells.

What is the significance of memory in immunity?

Both humoral and cellular immunity possess immunological memory, which allows the immune system to recognize and respond more quickly to pathogens it has encountered before, providing long-lasting protection.

How does immunity function in immunodeficient individuals?

In individuals with immunodeficiencies, either congenital or acquired, the immune system is less effective, and both cellular and humoral immunity may not function properly, leaving the person more susceptible to infections.