Vaccines
Vaccines1 are substances put into the blood to protect the body from a disease. They are made through several different processes. They may contain live viruses that have been attenuated; inactivated or killed organisms or viruses; inactivated toxins or segments of the pathogen.
Attenuated vaccines can be made in several different ways. Some of the most common methods involve passing the disease-causing virus through a series of cell cultures or animal embryos. Eventually, the attenuated virus will be unable to replicate well, or not at all, in human cells, and can be used in a vaccine.
One alternative to attenuated vaccines is a killed or inactivated vaccine. Vaccines of this type are created by inactivating a pathogen, generally using heat or chemicals. This destroys the pathogen’s ability to replicate, but keeps it intact so that the immune system can still recognise it.
Some bacterial diseases are not directly caused by a bacterium itself, but by a toxin produced by the bacterium. Immunisations for this type of pathogen can be made by inactivating the toxin that causes the disease symptoms.
Vaccines which only use segments of the pathogens are called subunit and conjugate. Subunit vaccines use only part of a target pathogen to provoke a response from the immune system. Conjugate vaccines are made using a combination of two different components. 2
Immunoglobulins
An immunoglobulin, also called gammaglobulin, is a large Y-shaped protein produced mainly by plasma cells and is used by the immune system to neutralise pathogens such as bacteria and viruses.
Gammaglobulin is also a clinical name given to the immunoglobulin concentrates that are given to humans for immunoprophylaxis against infectious disease or for passive antibody replacement in immunodeficiency diseases.
As immunoglobulins are in general very large molecules and do not pass into milk, they are given directly to infants – they are not contraindicated for newborns and breastfeeding mothers.
WARM UP
Do you know the difference between vaccines and immunoglobulins?
a. Vaccines are for children and immunoglobulins for adults.
b. Vaccines are used on healthy people, immunoglobulins are used when people are already sick.
c. Some vaccines are compulsory, while immunoglobulins are not.
DO
1 Do you know where the word vaccine comes from?
DO
2 Watch the video.
NOVA/Immunity and vaccines explained
posted by PBS
a. What are memory cells?
b. What does a vaccine do?
