Question

In your own words, briefly explain what the difference is between active and passive immunization. Incorporate the following terms in your answer: vaccine, antigen, attenuated, primary immune response, antibodies, serum, and immediate immunity.

Answer 1

	Active immunization	Passive immunization
Vaccine	The individual acquires resistance power through natural infections. For examples persons attacked by measles and smallpox develops natural active immunity as he recovers from the disease. One of the examples of artificial active immunization is vaccination or taking of vaccine for preventing infection in future	No involvement of vaccine here. The passive immunization is nothing but the individual (non-immune) acquires by receiving antibodies or sensitized white blood cells from another immune individual known as passive immunity.
Antigen	The naturally acquired pathogens act as an antigen (antigen is a part of pathogen or protein, cell wall, DNA or RNA of the pathogen) and stimulate the immune system due to that there is the production of antibodies in the individual.	There is no presence of antigen and no production of antibodies
Attenuated	The live (for bacteria) or attenuated (for viruses) microorganisms (in the form of vaccine) are possess the antigenicity but lack the virulence or pathogenicity and when they enter into the body and act as an antigen and stimulates the immune system and produces antibodies. These organisms are live and divides and constantly stimulates immune system and gives strong immunity or lifelong immunity	There is no such kind of reaction
Primary immune response	The first exposure to the antigen or natural infection and production of antibodies known as the primary immune response. It takes 1 week for production of antibodies for particular antigen/ natural pathogen	Primary immune response absent
Antibodies	The antibodies are produced inside the individual due to natural infection or artificial injection of vaccines	Antibodies are taken from another immunized individual in the form of pooled gamma globulins
Serum	The serum has less titer for antibodies against natural infection or pathogen or vaccines. In the case of vaccines, they need to take booster doses for production of more/strong antibodies in the serum	The serum collected from the persons recovering from particular disease contains the high number of antibodies for the specific antigen. This serum generally used for passive immunization against viral infections such as measles and rubella
Immediate immunity	It is absent and takes 5-8 days for production of antibodies	Passive immunization act as a immediate immunity. There is no latent period and protection occurs immediately.