Types of Immune Responses: Innate vs Adaptive Systems
Immune System And Immunology
Immunology can be defined as the study of the immune system and the cell-mediated and humoral aspects of the immunity and the immune responses. Immunology is a branch of biology that is involved in the study of the immune system, the biological processes of the immune system, components of the immune system, the types of the immune system, its disorders, and the functioning of the immune system to name a few aspects about immunology.
The immune system present in the body acts as a defense system to protect our body cells, tissues, and organs from the dangerous infections invading through the various lines of defence. The immune system functions as a physical barrier to prevent the entry of the disease-causing pathogens that include the harmful microorganisms and the other infectious microbes.
In cases, when our immune system stops functioning or functions poorly, this results in infectious diseases like fever, flu, allergies, and can also lead to life-threatening diseases like cancer, etc.
Immune System
The human immune system comprises the different types of cells and molecules that are responsible for protecting our body against pathogens. The pathogens are the parasites, fungi, viruses, bacteria, and haptens, etc. that enter our body and cause us to fall sick. Haptens are the molecules that can cause an immune system to respond when it comes to the contact of a protein. All of these cells and molecules are distributed in all of the tissues and the cells of the body as well as the lymphoid organs that are responsible for eliminating the microbial infectious diseases to prevent the growth of tumors and also to initiate the process of repairing the damaged tissues. The tissues and the organs involved in the immune system act as the security forces in which the cells act as the security guards, and the molecules act as bullets that are used as a communication system to overcome the attack of the pathogens and to protect our bodies from the diseases.
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Types of Immune System
The immune system present in humans is of two types, and they can be classified on the basis of the resistance and the power to fight against the harmful invading agents. They are the innate immune system and the adaptive immune system.
Innate Immune System: The innate immune system comprises the cells and the proteins that are there in the body and are always ready to fight against the microbes in the infection area. The innate immune system is present from the time we are born, and the main elements in the innate immune system include natural killer (NK) cells, circulating plasma proteins, dendritic cells, physical epithelial barriers, and the phagocytic leukocytes.
Adaptive Immune System: This immune system is required to fight against the pathogens that control the innate immune system defences. Since this immune system is acquired by us during the course of our lifetime, it is also referred to as the Acquired Immune System. The components in the Adaptive Immune System are generally inactive, but they get activated when these components adjust themselves according to the presence of the infectious agents by proliferating and developing a potent mechanism that fights to eliminate the microbes. The two types of adaptive responses are humoral immunity moderated by the antibodies that are developed by the B lymphocytes and the cell-mediated immunity and are moderated by the T lymphocytes.
Immunology and Diseases
Generally, the diseases occur due to the fundamental defects in the immune system. When the bodies are exposed to the pathogens, the immune system gets challenged to evoke the responses that, in lieu of protecting the cells and tissues, damage them. The immunodeficiency diseases are known to increase the risk of the infections, and the tumours that are caused by gene mutations, viruses like HIV and malnutrition.
Symptoms of Immune Dysfunction
The symptoms of the weaker immune systems and the immune dysfunction are as follows: -
Rhinitis or a constant runny nose
Bowel disorders
Painful joints and muscles
Allergies and Asthma
Frequent colds and flu
Herpes (cold sore) outbreak
Autoimmune disorders
Candida overgrowth
HPV and abnormal PAP smears
Parasite infections
Psoriasis, eczema, hives, or rashes
Immunological Techniques
The immune system structure and its functions can be studied through an experimental method and the different techniques that are used for the same include: -
ELISA
Isolation and Purification of Antibodies
ELISPOT
Immunohistochemistry
Generation of Antibodies
Immune cell isolation
Immuno-blotting and precipitation
Immuno-histo-chemistry
Applications of Immunology
Immunology can be used in several disciplines like medicine, oncology, virology, organ transplantation, psychiatric disorders, parasitology, rheumatic diseases, and dermatology, to name a few. The immunology in the transplantation process generally deals with the process of transplantation from the donor to the recipient.
FAQs on Immunology: The Immune System Explained
1. What is immunology?
Immunology is the branch of biology that studies the immune system, which is the body's defence mechanism against infectious organisms and other invaders. It involves understanding how the body distinguishes between its own cells (self) and foreign substances (non-self), and the physiological processes involved in neutralising and removing these foreign threats.
2. What is the difference between innate and acquired immunity?
The primary difference lies in their specificity and memory. Innate immunity is the non-specific defence mechanism that is present from birth. It acts as the first line of defence and includes physical barriers like skin and mucous membranes. In contrast, acquired immunity is pathogen-specific, develops over a lifetime after exposure to an antigen (e.g., through infection or vaccination), and is characterised by immunological memory.
3. What are the key components of the human immune system?
The human immune system is a complex network of cells, tissues, and organs. Its key components include:
- Lymphoid Organs: These are where lymphocytes are formed and mature. They include primary organs (bone marrow and thymus) and secondary organs (spleen, lymph nodes, tonsils).
- Immune Cells: These include lymphocytes like B-cells and T-cells, which are crucial for acquired immunity, and phagocytes like macrophages.
- Antibodies: These are proteins produced by B-cells that circulate in the blood and help neutralise pathogens.
4. What are antibodies and what are their main types found in the body?
An antibody, or Immunoglobulin (Ig), is a Y-shaped protein produced by B-lymphocytes in response to an antigen. Its function is to identify and neutralise foreign objects like bacteria and viruses. There are five main types in the human body: IgA, IgM, IgE, IgG, and IgD, each with a specific role in the immune response.
5. How do T-cells and B-cells differ in their roles in the immune response?
B-cells and T-cells are the two main types of lymphocytes, but they command different arms of the immune system. B-lymphocytes are responsible for humoral immunity; they produce antibodies that circulate in the body's fluids or 'humors'. T-lymphocytes are responsible for cell-mediated immunity (CMI); they do not produce antibodies but instead directly attack infected host cells, activate other immune cells, or regulate the immune response.
6. Why is a second immune response always faster and more intense than the first?
A second immune response is stronger due to immunological memory. During the first (primary) encounter with an antigen, the body produces effector cells to fight the infection and also long-lasting memory B-cells and T-cells. Upon a second exposure to the same antigen, these memory cells are quickly activated. This leads to a rapid and massive production of antibodies and T-cells, resulting in a quicker and more effective secondary (anamnestic) response that often prevents the disease from developing.
7. What is the principle behind vaccination?
Vaccination works on the principle of immunological memory. It involves introducing a preparation of killed, weakened, or inactivated pathogens (or their antigens) into the body. This safely stimulates a primary immune response without causing the actual disease. As a result, the body produces memory B-cells and T-cells. If the person is later exposed to the real pathogen, these memory cells trigger a swift and powerful secondary immune response, effectively neutralising the threat before it can cause illness.
8. What is an autoimmune disease? Explain with an example.
An autoimmune disease is a condition in which the body's immune system loses its ability to differentiate between self and non-self cells and begins to attack its own healthy tissues and organs. A prominent example as per the CBSE syllabus is Rheumatoid Arthritis, where the immune system attacks the membranes around the joints, causing chronic inflammation and pain.
9. How are immunological principles applied in modern diagnostic tests like ELISA?
Modern diagnostic tests like ELISA (Enzyme-Linked Immunosorbent Assay) are based on the highly specific principle of antigen-antibody interaction. To detect an infection, a patient's blood serum can be tested for the presence of specific antibodies (produced against a pathogen) or the antigen itself. In the test, a specific antigen/antibody is bound to a plate, and if the corresponding antibody/antigen is present in the sample, it binds. This binding is detected by a colour change produced by an enzyme, confirming the presence of the disease.
10. Who is considered the 'Father of Immunology' and what was his key contribution?
Edward Jenner is widely regarded as the 'Father of Immunology'. His crucial contribution was pioneering the concept of vaccination in 1796. He observed that milkmaids who had contracted the mild disease cowpox were immune to the deadly smallpox. He scientifically tested this by inoculating a boy with cowpox pus and later exposing him to smallpox, proving that the boy was protected. This groundbreaking work laid the foundation for the entire field of immunology and vaccination.
