Innate Immunity
- Innate immunity is the naturally-occurring immunity generated through genetic factors and the body’s physiology.
- Innate immunity begins at birthand continues throughout one’s life.
- The prior exposure to pathogens is not required by the innate immunity.
- The removal of pathogens via the natural immunity happens either in the internal organs or outwardly.
- External defense functions as the first line of defense against pathogens and is accomplished through the biological and chemical barrier.
- Saliva, tears mucus linings, stomach acid, and a few of the bacteria that reside in the gut function as barriers that prevent the entry of pathogens into cells of your body.
- The second line of defense is the defense mechanisms within the immune system that is innate.
- Different types of phagocytes function as internal barriers, stopping the proliferation and growth of pathogens in the tissues.
- Macrophages, natural killer cells neutrophils, monocytes, mast cells and dendritic cell are examples of cells that are involved in immune system’s innate. These cells kill pathogens via their phagocytosis. They also stimulate the complement system in the body and also adaptive immunity.
- Both internal and external mechanisms of innate immunity produce non-specific immune responses to pathogens.
Adaptive Immunity
- Adaptive immunity is a term used to describe an acquired immunity controlled by T cells and B cells.
- It is distinguished by an immunelogical memory. It is the third line of defense of the body.
- The activation of adaptive immunity happens as a result of an overthrow of the second line barrier caused by a particular pathogen.
- Cell-mediated immunity and humoral immune are the two kinds that are adaptive.
- Cell-mediated immunity is caused by cytotoxic T cells which cause the death of the infected cells.
- Helper T cells are the second kind of T cells which stimulate B cells to create antibodies.
- Producing specific antibody to specific pathogens occurs within humoral immunity. Because of its capacity to be able to react to a vast range of pathogens immunity is thought to have more variety.
- After it has responded to a specific pathogen it’s adaptive immune system stores the pathogen’s memory and develops a robust immune response after the second exposure.

Difference between innate and acquired immunity
Characteristics | Innate Immunity | Adaptive Immunity |
Definition | This refers to the natural-occurring immunity that is triggered by the genetic components and the body’s physiology. | Adaptive immune is a term used to describe an acquired immunity that is dependent on T cells and B cells. It is also characterized by an immune memory. |
Alternative Names | Innate Immunity is referred to by its natural Immunity. | It is also known as acquired immunity. |
Specificity | Innate immunity generates a non-specific immune response. | Adaptive immunity generates a specific immune response. |
Presence | Innate immunity is always present in the body. | Adaptive immunity only occurs in response to exposure to an external factor. |
Response | Since innate immunity provides the first line defense against the pathogens, it generates a rapid response. | Adaptive immunity is delayed 5-6 days. |
Components | Plasma proteins, phagocytes, physical and chemical barriers are the components of the innate immunity. | Humoral and cell-mediated immunity are the components of the adaptive immunity. |
Physical and Chemical Barriers | Temperature, pH, skin, and mucous membranes are the barriers of the innate immunity. | Lymph nodes, spleen, and lymphoid tissues are the barriers of the adaptive immunity. |
Memory Cells | Innate immunity does not develop memory cells. | Adaptive immunity develops memory cells. |
Diversity | Innate immunity possesses a less diversity. | Adaptive immunity possesses a higher diversity. |
Potency | Innate immunity is less potent. | Adaptive immunity exhibits a higher potency. |
Allergic Reactions | Innate immunity does not produce allergic reactions. | Adaptive immunity develops allergic reactions; immediate and delayed hypersensitivity. |
Activation of the Complement System | Innate immunity activates the complement system through the alternative and lectin pathway. | Adaptive immunity activates the complement system through the classical pathway. |
Time Span | Once developed for a particular pathogen, the innate immunity remains throughout the lifetime. | Adaptive immunity can last for the lifetime or for a short period of time. |
Inheritance | Innate immunity is inheritable. | Adaptive immunity is not inheritable. |
Cells involved | Dendritic leukocyte, Natural killer cells, Mast cell, Granulocytes/ Macrophages, Basophils, etc. | Killer CD8+ T-cells, Helper CD4+ T-cells, B-cells, Antigen presenting cells, etc. |
Molecules involved | Cytokines, Complement cells, Interferon, Acute phase reactants/ proteins | Antibodies, Cytokines |
Receptors | Germline encoded No somatic rearrangement Non-clonal distribution | Encoded in gene segments Somatic rearrangement necessary Clonal distribution |
Action time | Immediate effector activation | Delayed effector activation |
Order of defence | It is the first line of defense of immune system | Action against pathogens that are able to evade or overcome innate immune defense |
Subsequent exposure | Immune response does not get alter on repeated exposure . | Immune response get improves with subsequent exposure. |
Allery or | None | Immediate and delay |
Reason behind immune evasion | Caused by pathogenic virulence | Caused by mutation of the recognized antigen |
Development | Evolutionary, older and is found in both vertebrates and invertebrates. | Adaptive immunity system has been developed recently and is found only in the vertebrates. |
Diversity | Limited | High |
Examples | The redness and swelling caused by white blood cells around a wound is an example of an innate immune response. | Vaccination against a virus is an example of adaptive immunity. |
References
- https://pediaa.com/difference-between-innate-and-adaptive-immunity/
- https://microbiologyinfo.com/difference-between-innate-and-adaptive-immunity/