Innate immunity is a part of immune system which exists from birth of an individual.
It is also called as natural immunity as it is a basic method of defense.
This is first line of defense against any microbial attacks to the baby.
This natural immunity is essential for the survival of the tender infant who is delicate and susceptible to many environmental microorganisms attack once out of the mother womb.
Innate immunity is comprised of 4 basic defense methods which mostly run through out the entire life of the individual.
It helps in saving us from infectious attacks in almost every moment of life.
Examples of Innate Immunity
The examples consists of
1. Physical barriers
2. Physiological barriers
3. Cellular barriers and
4. Cytokine barriers
Physical barriers: This includes skin and mucous membranes. Skin cover all the visible and environment exposed areas of the body. It is thick, hard and keratinsed making it tough for any microbes to enter the body through.
If there is a wound or cut which exposes the internal tissues, there is chance of immediate attack of microbes on to the injury. Hence, we will notice formation of pus and other secretion which fight with infectious bacteria and other microbes from gaining entry into the body. This last till the injury is cover by new skin tissue or scar during the process of healing. This pus is formed due to the rush of white blood cells to arrest the area from infection and enhance the speed of healing.
Mucous is another physical barrier and unlike skin it is a coating on the inner surfaces of digestive tract, intestine, respiratory system, mouth which are frequently exposed to air, food, water from external source. Mucous unlike skin is a temporary cover is shed frequently and also formed frequently. It is moist and thick and enables removal of any microbes from the body.
So physical barriers like skin and mucous are examples of innate immunity.
Physiological barriers: As the name implies, these are the ones which are released or formed as a part of body regular physiology. These include
b) Hydrochloric acid in the stomach
c) Tears in the eyes.
These three secretions prevent microbes from gaining entry in to the body.
Saliva is secreted by salivary glands to keep the mouth moist. This saliva has a metabolic enzyme lysozyme in it which kills microbes present in the buccal cavity.
Hydrochloric acid is released in the stomach keeping the pH at 1.5. This acidic pH leads to degradation of protein of food as well as the microbes. Thus many microbes are killed in the process and prevent chances of infection from food.
Tears in the eyes have many antimicrobials like the enzymes lysozyme, lactoferrin, lipocalin, secretory immunoglobulin A (IgA), enzyme secretory phospholipase A2, Secretory leukocyte protease inhibitor which kill the microbes trying to adhere to the eye surface.
Besides there are few cationic antimicrobial peptides and surfactant protein which help in destroying the microorganisms from entering the body through the eye.
These are immune cells in the body which kill any pathogen roaming inside the body.
They keep moving through out body tissues and blood and engulf (cell eating) the microbes when encountered.
These include a) Neutrophils b) Monocytes and c) Lymphocytes.
Cytokine barriers: This is meant to keep viruses at bay. When few cells are infected with virus, these cells secrete interferons which