Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The principle of immunization or vaccination is based on the property of 'memory' of the immune system. When a vaccine is introduced into the body, it generates memory and cells that recognize the pathogen quickly on subsequent exposure.
Vaccination involves the introduction of a preparation of antigenic proteins of a pathogen or inactivated/weakened pathogens (vaccine) into the body to stimulate the production of antibodies.
Passive Immunization is the process of providing ready-made antibodies directly to the body. This is required when an immediate immune response is necessary, such as in cases of Tetanus or snake bites (where antitoxins containing antibodies to the venom are administered).
Active Immunization involves the body's own immune system producing antibodies in response to an antigen. This can be natural (after an infection) or artificial (via vaccination).
Recombinant DNA technology has allowed the production of antigenic polypeptides of pathogens in bacteria or yeast. This allows for large-scale production of vaccines, such as the Hepatitis vaccine produced from yeast.
Antibodies are specialized proteins produced by -lymphocytes. Each antibody molecule has four peptide chains: two small light chains and two longer heavy chains, represented by the formula .
📐Formulae
💡Examples
Problem 1:
Why is it that a person who has suffered from chickenpox once is unlikely to suffer from it again?
Solution:
This is due to the development of naturally acquired active immunity and the presence of memory cells.
Explanation:
During the first encounter with the varicella-zoster virus, the body produces a primary immune response and creates memory and cells. Upon a second encounter, these memory cells elicit a highly intensified secondary (anamnestic) response, neutralizing the pathogen before it can cause disease symptoms.
Problem 2:
Differentiate between the type of immunity provided by a Tetanus vaccine and a Tetanus antitoxin injection.
Solution:
Tetanus vaccine provides Active Immunity, while Tetanus antitoxin provides Passive Immunity.
Explanation:
The Tetanus vaccine contains inactivated toxins (toxoids) that stimulate the body to produce its own antibodies and memory cells over time. The Tetanus antitoxin contains pre-formed antibodies that provide immediate protection against the toxin, which is crucial if a person is already exposed to the danger.
Problem 3:
How is the Hepatitis vaccine manufactured using modern biotechnology?
Solution:
It is produced using Recombinant DNA technology in yeast cells.
Explanation:
The gene encoding the surface antigen of Hepatitis virus () is inserted into yeast cells (). These recombinant cells then express the viral protein, which is purified and used as a vaccine to stimulate an immune response without using the actual virus.