Differences Between Innate And Adaptive Immunity

Health is the state of the body and mind. Health does not simply mean physical fitness or the absence of disease. It is a state of complete mental, physical, and social well-being. A balanced diet, regular exercise, and personal hygiene are important for maintaining good health. 

Immunity 

The ability of an organism to fight against the disease-causing organism is known as immunity. Immunity is of two types- Innate immunity and Adaptive/acquired immunity.

Innate immunity

Innate immunity is a non-specific immunity that is present at the time of birth. Different kinds of barriers to the entry of foreign agents into our bodies accomplish this. There are mainly four types of barriers to innate immunity.

1. Physical or Anatomical barrier

• Physical or anatomical barriers are of two types. It includes skin and mucosa.
• Skin: Skin is the main barrier preventing microorganisms entry. As the outermost layer of skin is dead, microorganisms such as bacteria do not grow or enter it. Moreover, the skin’s pH is acidic, destroying the bacteria.
• Mucosa: The epithelium of respiratory, gastrointestinal, and urogenital tracts are lined by mucus. It traps the microorganisms entering our bodies. Mucosa contains cilia and mucosal cells. Mucosa traps the microorganisms, and cilia propel the microbes.

1. Physiological barriers

• Some physiological processes of the body create adverse environments for the growth of bacteria. 
• Acid in the stomach, saliva in the mouth, and tears from the eyes all prevent the growth of microorganisms.
• Fever: High temperature of the body inhibits the growth of microorganisms.
• Ph of the body; Acidic pH inhibits the growth of the microorganisms in the oral cavity, stomach, and vagina, inhibiting the growth of microbes.
• Secretions: Secretions of the body, like eyes and saliva contain lysozyme; this enzyme destroys the microbes.

1. Cellular barriers

• Neutrophils (polymorphonuclear leukocytes), monocytes, natural killer cells in the blood, and macrophages in tissues, can phagocytose and destroy microbes. These cells are of two types- phagocytic cells and non-phagocytic cells.
• Phagocytic cells include monocytes, neutrophils, and macrophages. The total count of WBCs in the body increases in response to pathogenic infection. Some types of WBCs exhibit phagocytosis; such WBCs are known as phagocytes.
• Most important phagocytes are macrophages and neutrophils. Monocytes are released at the site of infection. They later are converted into macrophages in tissues
• Macrophages are large, irregularly shaped cells that engulf microbes, viruses, cellular debris, etc., in response to an infection.
• Non-phagocytic cells include natural killer cells (NK cells). NK cells are large granular lymphocytes. In innate immunity, NK cells kill virus-infected cells and tumor cells of the body by creating perforin-lined pores in the target cell’s plasma membrane. When water enters these cells, it causes swelling and bursting of these cells.

1. Cytokine barrier

• Virus-infected cells secrete proteins known as interferons. Interferons protect the nearby cells from further virus infection.
• Interferon are anti-viral proteins comprising 270 amino acids secreted by virus-infected cells and stimulate the adjacent cells to produce the Translating Inhibiting Protein (TIP).
• Through this mechanism, interferon limits the infection of the virus.
• Interferons are species-specific; interferons produced by the same species protect cells of the same species.
• Interferons makes cell resistant to viral infection by synthesising antiviral proteins in that cell.
• Interferons can be used for the prevention and treatment of viral infection.

Inflammation

Inflammation is a local response in a living mammalian tissue in response to injury due to any agent. It is the body’s defense mechanism to limit the spread of infection or to eliminate the infection. It is characterised by-

• Erythema/redness/rubor due to vasodilation.
• Heat/calor due to rapid metabolic reactions going at the site of inflammation.
• Tumor or swelling due to enhanced permeability of blood vessels.
• Pain/dolor results due to injury to neurons and different chemicals released by damaged cells. 

Adaptive immunity

• Adaptive immunity is also known as acquired immunity. They are pathogen-specific and are characterised by memory. It means when our body encounters a pathogen for the first time, it produces a response known as the primary response, which is less intense. When subsequent encounters occur with the same pathogen, it elicits a highly intensified secondary or anamnestic response. This indicates that our body appears to remember the first encounter.

Characteristics of adaptive immunity

1. Specificity: Adaptive immunity is specific for specific microorganisms.
2. Diversity: Various microorganisms can be identified via adaptive immunity.
3. Discrimination between self and nonself: It can recognise self, body or tissue and nonself and responds accordingly.
4. Memory: When a pathogen enters the body, the body takes longer times to recognise and respond to it; this is known as the primary response. 

When a similar pathogen enters the body a second time, the immune system rapidly recognises the pathogen and responds quickly to it. This is called secondary or anamnestic response.

The primary and secondary immune responses are carried out with the help of two special types of lymphocytes present in the blood. They are known as B-lymphocytes and T-lymphocytes. The B-lymphocytes produce an army of proteins known as antibodies in response to the pathogen in our blood. T cells do not secrete antibodies, but help B cells produce antibodies.

Types of adaptive immune response 

Humoral immune response and adaptive immune response are types of the adaptive immune response.

Humoral immune response

• The blood cells carry and distribute the antibodies made by B-lymphocytes throughout the body. Because it includes an antibody from lymphocytes, it is called the humoral immune response.
• It depends on how antibodies moving throughout the body are acting. Humoral immunity is activated when an antibody on a B-cell interacts to an antigen. The helper T cell is exposed to the antigen after the B cell has internalised it. This triggers the B-cell.
• The B cells that have been stimulated develop into plasma cells. Antibodies are released into the bloodstream by these plasma cells. To stop any disease brought on by that pathogen shortly, the memory B cells store information about the pathogen.

Cell mediated immune response 

• The T helper cells start cell-mediated immunity.
• By releasing toxins, the cytotoxic T cells destroy the infected cells from the body and encourage apoptosis, or programmed cell death.
• Other immune cells are stimulated by the T helper cells.
• T helper cells are important at the time of organ transplantation. Replicating one of our sense organs to replace another when one stops working is possible. 
• With the immunological response, though, things are more complicated. It indicates that T-lymphocytes can distinguish between tissue or organs from our body and foreign bodies. 
• Because our bodies could reject the transplanted organ, we cannot transplant or implant organs into our bodies, even if we discover a donor with the same blood group.
• The T-cells instantly identify the tissue or organ as alien and prevent it from assimilating into the body. Because of this, immunosuppressant medicine is required for the rest of the recipient’s life. T lymphocytes control this response. 

Differences between Innate and Adaptive immunity

FAQs

1. What is acquired immunity?

A form of immunity that arises after a person acquires antibodies from another source or when their immune system reacts to a foreign material or bacterium is known as acquired immunity. Adaptive immunity is also known as acquired immunity.

1. What is innate immunity?

Innate immunity, or nonspecific immunity, is the defence mechanism you were born with. Barriers that prevent harmful substances from entering our body is a part of innate immunity. These barriers serve as the immune system’s first line of defence.

1. What is inflammation?

Inflammation is a local response of living mammalian tissue to injury due to any agent. It is a body defense mechanism to limit the spread of infection or to eliminate the infection.

1. What is interferons?

Virus infected cells secrete proteins known as interferons. Interferons protects the nearby cells from further virus infection.

1. What are cytokines?

Small proteins called cytokines are key in regulating blood and immune system cell development and activity. They signal the immune system once they are released. All blood cells and other cells that support the body’s immunological and inflammatory responses are affected by cytokines.