summary notes

Question 1

describe innate immunity

Answer 1

• first
• fast
• no specificity/memory

Question 2

describe adaptive immunity

Answer 2

• specificity
• memory
• tolerance

Question 3

list components of innate immunity

Answer 3

1. barriers
2. cellular
   - phagocytes, eosinophils, basophils, mast cells, natural killer cells, t cells
3. humoral
   - complement, soluble mediators, pattern-recognition receptors, b cells

Question 4

describe all t cells

Answer 4

role in innate & adaptive immunity

has a tcr on surface

1. T helper/ Th (CD4+) : produce cytokines
2. T killer/Tc (CD8+): secrete IFN gamma and kill cells

Question 5

describe Th cells

Answer 5

Th1

• secretes IL2, interferon gamma, tumour necrosis factor
• important in host defence against intracellular pathogens
• important in disease: autoimmunity and chronic inflammation

Th2

• secretes IL4, IL5, IL13
• important in host defence against helminths
• important in disease: allergy

Th17

• secretes IL17, IL22
• important in host defence against extracellular bacteria & fungi
• important in disease: autoimmunity and inflammation

Question 6

describe b cells

Answer 6

produce antibodies (igG, igM, igA, igE, igD)

• antigen binding
• neutralisation
• immune complex formation
• opsonisation
• complement activation
• cellular cytoxicity

Question 7

what are the lymphoid tissues

Answer 7

primary: thymus, bone marrow
- t & b cells mature; deletion of cells responding to self antigens

secondary: lymph nodes, spleen, tonsils, adenoid, intestine/peyer’s patches
- lymphocyte response to foreign antigen intiated

Question 8

describe antigen recognition

Answer 8

b cells recognise antigen directly via immunoglobulin

t cells recognise antigen that are degraded and processed by antigen presenting cells (APC) and presented in association with HLA molecules on surface

Question 9

describe MHC (major histocompatibility complex)

Answer 9

gene codes for cell surface proteins that present antigen to t cells
in humans, the complex is called HLA

• class I: present epitopes to the TCR of CD8+ T cells (Tc)

- class II: present epitopes to the TCR of CD4 T cells (Th)
macrophages, b cells, dendritic cells

Question 10

what is tolerance

Answer 10

unresponsiveness to self tissue

• central: negatively selected and apoptosis
• peripheral: anergy, t regulatory cells