Immunity following infection lasts up to 19 months
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Immunity following infection lasts up to 19 months
Subject: Science
Section: Basic
Context: Study undertaken in Sweden has once again found irrefutable evidence in support of vaccination, even among people who have been previously infected.
Findings:
What is Immunity? Immunity is the capability of multicellular organisms to resist harmful micro organisms. Immunity involves both specific and nonspecific components.
Innate Immunity
- Innate immunity is non-specific type of defense that is present at the time of birth.
- Innate immunity is accomplished by providing different types of barriers to the entry of the foreign agents into our body.
- Innate immunity consists of four types of barriers. These are;
- Physical Barriers: Skin on our body is the main barrier which prevents entry of the micro-organisms.
- Physiological Barriers: Acid in the stomach, saliva in the mouth, tears from eyes-all prevent microbial growth.
- Cellular Barriers: Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes.
- Cytokine Barriers: Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection.
Acquired Immunity
- Acquired immunity is pathogen specific. It is characterized by memory. This means that our body when it encounters a pathogen for the first time produces a response called primary response which is of low intensity.
- Subsequent encounter with the same pathogen elicits a highly intensified secondary or anamnestic response. This is ascribed to the fact that our body appears to have memory of the first encounter.
Active and Passive Immunity
- When a host is exposed to antigens [a substance which the body recognizes as alien and which induces an immune response], which may be in the form of living or dead microbes or other proteins, antibodies are produced in the host body. This type of immunity is called active immunity.
- When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.
Vaccination and Immunization
- In vaccination, a preparation of antigenic proteins of pathogen or inactivated / weakened pathogen (vaccine) is introduced into the body.
- The antibodies produced in the body against these antigens would neutralize the pathogenic agents during actual infection.
Hybrid Immunity
https://optimizeias.com/hybrid-immunity/
Antibodies and Cellular Immunity