The Immune Response

- Overview

The immune system protects the body against illness and infection that bacteria, viruses, fungi or parasites can cause. It is a collection of reactions and responses that the body makes to damaged cells or infection. So it is sometimes called the immune response.

Additionally, a strong immune system helps the body fight off HIV, cancer, malaria, dengue fever, and other diseases. Therefore, people with immune or autoimmune diseases should seek immediate help from an immunologist. In recent decades, scientists in the field of immunology have published research showing a direct link between immune system dysregulation and disease development. 

An excessive immune response can lead to conditions such as Crohn's disease or asthma. Autoimmune diseases, such as rheumatoid arthritis, in which the immune system cannot distinguish foreign cells from "self" cells can severely impact quality of life. 

The immune system is even now considered a major contributor to Alzheimer's disease pathology, with several studies exploring the impact of viral infection on the development of psychiatric symptoms.

- The Two Branches of the Immune Response

The immune response is the body's complex defense against foreign invaders like bacteria, viruses, and other harmful substances, which involves a two-branched system: the rapid, general innate immune response and the slower, highly specific adaptive immune response. 

The innate system provides immediate, non-specific protection, while the adaptive system develops a targeted attack and a memory of the invader, allowing for a faster and more effective response to future encounters. 

The Two Branches of the Immune Response: 

1. Innate Immune Response: 

• First Line of Defense: This is the body's immediate, non-specific defense, ready to act before any specific threat is even identified.
• Key Mechanisms: It includes physical barriers like skin, chemical barriers like mucus, and cells called phagocytes that engulf and destroy pathogens.
• Inflammation: This is a key part of the innate response, occurring when tissues are injured and attracting white blood cells to the site of injury to clean up and repair.
• Antigen-Presenting Cells: Cells like macrophages and dendritic cells engulf and process foreign substances and present their antigens to the adaptive immune system, initiating a more specific response.

2. Adaptive Immune Response: 

• Specific Defense: This response is highly specific, recognizing particular antigens on foreign molecules and mounting a targeted attack.
• Lymphocytes: This branch primarily involves lymphocytes, a type of white blood cell.
• T Cells: Search for and kill infected cells, while also helping to coordinate the immune response.
• B Cells: Produce antibodies, which latch onto specific antigens and neutralize or mark the invaders for destruction.
• Immunological Memory: A critical feature of the adaptive response is its ability to "remember" specific pathogens, allowing for a quicker and more powerful response upon subsequent exposures.

3. How It Works Together: 

The innate and adaptive systems work together to protect the body from a wide range of threats. The innate response provides immediate protection and signals the adaptive system to mount a more specific and powerful defense when necessary, leading to the effective clearance of threats.

- Immune System Function, Conditions and Disorders

The immune system protects the body from pathogens like bacteria, viruses, fungi, and parasites, as well as damaged cells, through a series of responses that can be overactive, underactive, or misdirected. 

A robust immune system can fight off diseases like HIV and cancer, but a dysfunctional one can lead to autoimmune conditions, such as rheumatoid arthritis, where it attacks the body's own tissues, or excessive responses causing asthma and Crohn's disease. The field of immunology studies these dysfunctions to understand diseases and develop treatments, with immune system involvement even being investigated in Alzheimer's disease. 

1. How the Immune System Works: 

• Protection: The immune system acts as the body's defense against foreign substances (like bacteria and viruses) and internal threats (like damaged cells or cancer cells).
• Immune Response: This protection is achieved through a series of reactions and responses known as the immune response.
• Components: It is a complex network of cells, tissues, and organs, including white blood cells, antibodies, lymph nodes, the thymus, and the spleen.

2. Dysfunction and Disease: 

• Overactive Immune System: An overly strong or inappropriate immune response can lead to allergies, such as asthma, or inflammatory conditions like Crohn's disease.
• Autoimmune Diseases: In autoimmune diseases, the immune system fails to distinguish between foreign invaders and the body's own cells, leading to attacks on healthy tissues and causing conditions like rheumatoid arthritis.
• Link to Other Diseases: Research has also explored the immune system's role in diseases like Alzheimer's disease, particularly the impact of viral infections on psychiatric symptoms.

3. When to Seek Help: 

Individuals with autoimmune or immune-related diseases should seek help from an immunologist for proper diagnosis and treatment.

Immunologists are specialists who study the immune system and can help manage conditions caused by immune system dysregulation. 

[More to come ...]