Chapter 2: HIV And The Immune System Flashcards
What is active and passive immunity
Active immunity follows after infection by a pathogen but can also be generated by immunisation.
Passive immunity is short term immunity that newborn babies get from its mother.
What is an antibody
A special protein complexes produced by the immune system that attacks and neutralises specific disease causing organisms.
The antibodies created by the body in response to HIV are powerless to protect the body against the long term destructive effects of HIV.
What are CD4 Cells
CD4 T helper lymphocytes play an important role in keeping the immune system healthy. HIV attaches itself to these cell receptors on the outer layer of the CD4 cells.
Define macrophages
These are types of phagocytes that attack cells infected with viruses. they are antigen presenting cells meaning they present antigens to the lymphocytes and mobilize the lymphocytes to attack invaders.
Define seroconversion
It is the point at which a person’s HIV status changes from negative to positive. This coincides with the time when an HIV test will show that a person is positive which usually occurs 4-8 weeks after an individual is infected.
Explain non specific and specific defenses
Non specific defenses consist of the skin and an inflammatory response. They are non specific in the sense that they will attack any pathogen to try protect the body an example being macrophages.
Specific defenses specialise and attack specific pathogens that they are made to kill. CD4 cells have a specific specialisation and is to stimulate the rest of the immune system to produce more cells to fight off infection.
What is reverse transcriptase
It is a viral enzyme which helps in the copying of the virus inside the host cell and is injected with the viral genetic material into host cell during infection.
Define phagocytes
Are referred to as scavengers of immune system because they are white blood cells that engulf and destroy foreign or infected cells. There are 2 types namely macrophages and neutrophils
Define retro virus
A type of virus that replicates by changing its genetic RNA into DNA by use of the hosts cells
What are vaccines
It is a substance given to stimulate immune system to protect person from infection by a specific microorganism that are made from live pathogens
