Immunity & It's Types

 

Introduction:

Immunity refers to the body's ability to fight against harmful foreign substances, such as pathogens, that can cause disease. The immune system is a complex network of organs, tissues, cells, and molecules that work together to protect the body from infection and disease. In this article, we will discuss different aspects of immunity, including cell-mediated immunity, innate and acquired immunity, active and passive immunity, and the organs and cells of the immune system.

Innate Immunity:

Innate immunity is the first line of defense against pathogens. It is a non-specific response that includes physical and chemical barriers, such as the skin and mucous membranes, as well as cells like macrophages and neutrophils, that can engulf and destroy pathogens.

Acquired Immunity:

Acquired immunity is a specific response that develops over time in response to exposure to a specific pathogen or antigen. It involves the production of antibodies by B cells and the activation of T cells, which can recognize and eliminate specific pathogens.

Cell-Mediated Immunity:

Cell-mediated immunity is a type of acquired immunity that involves the activation of T cells. T cells are activated by antigens presented to them by antigen-presenting cells, such as dendritic cells. Once activated, T cells can differentiate into effector cells, such as cytotoxic T cells, that can directly kill infected cells, or helper T cells, that can activate other cells of the immune system.

Active Immunity:

Active immunity is the immunity that develops in response to exposure to a pathogen or antigen. It can occur naturally, through infection with a pathogen, or artificially, through vaccination. In active immunity, the body produces its own antibodies in response to the antigen, which provides long-term protection against the pathogen.

Passive Immunity:

Passive immunity is the immunity that is transferred from one individual to another. It can occur naturally, through the transfer of antibodies from a mother to her fetus or through breast milk, or artificially, through the injection of antibodies from an immune individual. Passive immunity provides immediate but short-term protection against the pathogen.

Organs and Cells of the Immune System:

The immune system includes a variety of organs and cells that work together to protect the body from infection and disease. Some of the major organs of the immune system include the thymus, bone marrow, lymph nodes, spleen, and tonsils. Cells of the immune system include lymphocytes, such as B cells, T cells, and natural killer cells, as well as phagocytes, such as macrophages and neutrophils.

Conclusion:

Immunity is an essential function of the human body that protects us from harmful pathogens and other foreign substances. The immune system is a complex network of organs, cells, and molecules that work together to provide this protection. Understanding the different types of immunity, including innate and acquired immunity, as well as the organs and cells of the immune system, is essential for understanding how the immune system works and how it can be manipulated to provide protection against disease.

Difference between Innate immunity and acquired immunity.

Innate and acquired immunity are two different types of immune responses that the body uses to defend itself against pathogens. The main differences between innate and acquired immunity are:

1. Specificity: Innate immunity is non-specific and responds to a broad range of pathogens, while acquired immunity is specific and targets particular pathogens.
2. Memory: Innate immunity does not have memory, meaning that it does not remember past infections and does not provide long-term protection. Acquired immunity, on the other hand, has memory and can remember past infections, which provides long-term protection against specific pathogens.
3. Speed: Innate immunity is a rapid response that occurs within minutes to hours of exposure to a pathogen, while acquired immunity takes several days to develop.
4. Components: Innate immunity involves physical and chemical barriers, such as the skin and mucous membranes, as well as cells like macrophages and neutrophils that can engulf and destroy pathogens. Acquired immunity involves the production of antibodies by B cells and the activation of T cells, which can recognize and eliminate specific pathogens.
5. Heritability: Innate immunity is inherited and is present from birth, while acquired immunity is acquired over time through exposure to pathogens or vaccination.

In summary, innate immunity is a non-specific, rapid response to a broad range of pathogens that does not provide long-term protection, while acquired immunity is a specific, slower response that provides long-term protection against particular pathogens.

Difference between Active and Passive immunity.

Active and passive immunity are two types of immunity that the body can use to defend itself against pathogens. The main differences between active and passive immunity are:

1. How immunity is acquired: Active immunity is acquired through the body's own immune response to a pathogen or vaccine, while passive immunity is acquired by receiving pre-formed antibodies from another source.
2. Duration of immunity: Active immunity provides long-lasting immunity because the body's immune system is activated and produces memory cells that can recognize and respond to future infections with the same pathogen. Passive immunity, on the other hand, provides immediate but temporary protection, because the pre-formed antibodies received from another source are eventually cleared from the body.
3. Timing of immunity: Active immunity takes time to develop, as the body's immune system needs time to recognize and respond to the pathogen or vaccine. Passive immunity, on the other hand, provides immediate protection because the pre-formed antibodies are already present in the body.
4. Sources of immunity: Active immunity can be acquired naturally through exposure to a pathogen, or artificially through vaccination. Passive immunity can be acquired naturally, such as the transfer of antibodies from mother to baby during pregnancy or breastfeeding, or artificially, such as the injection of pre-formed antibodies.
5. Flexibility: Active immunity is flexible and can be tailored to respond to a wide range of pathogens. Passive immunity, however, is fixed and cannot be tailored to respond to different pathogens.

In summary, active immunity is acquired through the body's own immune response and provides long-lasting protection, while passive immunity is acquired by receiving pre-formed antibodies from another source and provides immediate but temporary protection.