Immunity & Infection

Question 1

What parts of the body contribute to immunity?

Answer 1

Bone marrow, thymus gland, lymph nodes, spleen/tonsils

Question 2

What is a cell-mediated immune response?

Answer 2

Directed towards intracellular pathogens such as viruses, cancer cells & tissue transplants.

Question 3

What is the process of cell-mediated immunity?

Answer 3

Pre-T cells (immature) found in red bone marrow mature in the thymus to become mature T cells. CD4+ T cell is a helper cell that helps in the activation of the CD8+ T cell to become a KILLER CD8+ T cell which leaves lymphatic tissue to attack invading antigen.

Question 4

What is a humoral immunity (antibody-mediated) response?

Answer 4

Directed towards extracellular pathogens such as bacteria.

Question 5

What is the process of humoral immunity?

Answer 5

Mature B cells have antigen receptors. They are activated with the help of CD4+ T cells as they knock off the antibodies on the B cells which bind to and inactivate antigen.

Question 6

How do CD8+ T cells work? (natural killer cells)

Answer 6

Release perforin (protein) to cause autolysis which causes the organism to destroy itself.
Release lymphotoxin which causes apoptosis (early cell death) as the killer cells make foreign cells think that their time is up.

Question 7

What are the 6 actions of antibodies?

Answer 7

Agglutination, precipitation, neutralisation, lysis, opsonisation and activation of complement cascade.

Question 8

What is agglutination?

Answer 8

Make foreign cells clump together so they can stop functioning.

Question 9

What is precipitation?

Answer 9

Antibody & antigen combine to become insoluble.

Question 10

What is neutralisation?

Answer 10

Antibodies bind to virus and bacteria cells to make them incapable of attacking other cells.

Question 11

What is lysis?

Answer 11

Direct killing of that cell.

Question 12

What is opsonisation?

Answer 12

Antigen marks the cell - cells involved in phagocytosis act quicker.

Question 13

What is the activation of complement cascade?

Answer 13

Series of enzymes we have in our blood cause all the other functions of antibodies to occur but from a different perspective.

Question 14

Define infection.

Answer 14

An extension of inflammatory and immune processes and is a complication of immune function.

Question 15

What are the 7 types of pathogens?

Answer 15

Bacteria, viruses, fungi, protozoa, rickettsia, helminths, mycoplasma.

Question 16

What are the lab and diagnostic tests to diagnose an infection and how do they do this?

Answer 16

WBC count - rise when infected
Serum antibody levels - sees what they’ve potentially been exposed to before -> high in no. probs the infection they’re fighting.
Cultures - Take a sample and grow it on agar then can be grown with antibiotics to see which would kill it.
Sensitivities.