Immunity and Disease

Question 1

What is innate immunity?

Answer 1

Defence mechanism present even before infection or activated in a non-specific way

Question 2

Examples of innate immunity

Answer 2

Skin, mucous membrane, phagocytic cells (neutrophils, macrophages), inflammation, fever

Question 3

What is adaptive immunity?

Answer 3

Specific immunity that relies on antigens and lymphocytes. Cell mediated, humoural immunity

Question 4

Describe the non-specific responses to infection (How?)

Answer 4

Macrophages release protein signals interleukin-1 (IL-1) and interleukin-6 (IL-6).
Fever - most bacteria grow optimally at below body temperature.
Pain, swelling, redness - increased capillary permeability, promoting blood flow, bringing more phagocytic cells.
Acute-phase proteins released from liver - bind to bacteria and activate compliment proteins.

Question 5

What role does Bone Marrow have in adaptive response?

Answer 5

Produce lymphocytes.

B-cells mature in the bone marrow then concentrate in the lymph nodes and spleen.

Question 6

What do B-cells do in the adaptive response?

Answer 6

Secrete antibodies (glycoproteins with specific subtypes - IgG, IgM, IgA, IgE, IgD) - humoral immunity and recognise pathogens outside the cells

Question 7

What do T-cells do in the adaptive response?

Answer 7

Recognise antigen presented by histocompatibility complex. Directly attack invaders (cytotoxic, CD8+, MHC1) - cell mediated immunity, recognise pathogens that have entered the cell. Also help B-cells (helper cells, CD4+, MHC2)

Question 8

What are the different types of vaccines?

Answer 8

Live (attenuated) - live, weakened vaccine e.g. MMR
Inactivated - inactive part of pathogen (e.g. Hep B)
Toxoid - bacterial toxin e.g. Diphtheria
Conjugated - antigen linked to protein carrier (e.g. pneumoccocal)