Specific Resistance Flashcards
Helper T cells play an important role in both humoral and cellular immunity. They secrete a substance that:
- causes lympocytes at infection site to become sensitised
- attract macrophages to the place of infection to destroy antigens by phagocytosis
- intensify phagocytic activity of macrophages
What do killer T cells do?
Migrate to site of infection & deal with invading antigen. They attach to invading cells & secrete a substance that will destroy the antigen & then search for other antigens.
Suppressor T cells act when immune activity becomes excessive or the infection has been dealt with successfully - what substances do they release?
Suppressor T cells release substances that inhibit T/B cell activity slowing down the immune response.
What is an antigen?
A substance capable of causing specific immune response.
What is an antibody?
A specialised protein produced in response to a non-self antigen.
Antibodies in order to protect the body from a specific antigen may:
Combine with foreign enzymes to inactivate them by inhibiting reaction with other cells, bind to virus, coat bacteria to be more easily consumed by phagocytes, cause particles to clump (agglutination) or dissolve organisms.
What does antibody mediated immunity mean?
The body is working against bacteria, toxins & viruses before they enter the body’s cells; also against red blood cells of a different blood group than the person.
What does cell mediated immunity do?
Works against transplanted tissues and organs, cancer cells & cells infected by viruses or bacteria. It also provides resistance to fungi & parasites.
What occurs in humoral immunity after the foreign antigen reaches lymphoid tissue?
Certain B lympocytes are stimulated to undergo rapid cell division.
After rapid cell division, what occurs when relating to humoral immunity,
Most new B cells develop into plasma cells which produce antibodies & release them into blood and lymph.
What ensures a faster secondary response to an antigen?
Memory cells!
In cellular immunity after T lympocytes are stimulated to undergo rapid cell division, what occurs?
Most T cells develop into killer T cells or helper T cells which migrate to the site of infection.
After killer & helper T cells migrate to the site of infection, what occurs?
Killer T cells destroy the antigen whilst helper T cells promote phagocytosis by macrophages.
What is passive immunity?
When a person is given antibodies by someone else eg. Through placenta or breast milk or via bloodstream through an injection.
What is natural immunity?
Natural immunity occurs without human intervention.
