Pathology and Host Defence

Question 1

What are the two types of host immunity and what is the difference between the two?

Answer 1

Innate - slow and non specific
Adaptive - specific to bacteria and fast response

Question 2

What are the main components of innate immunity?

Answer 2

GCF
Complement
Neutrophils and macrophages
Barrier effect of intact epithelium

Question 3

In the space between the tooth and the sulcular epithelium, what fluid is present?

Answer 3

GCF

Question 4

Keratinised or not?
Oral Epithelium
Sulcular Epithelium
Junctional Epithelium

Answer 4

Keratinised
Non keratinised
Non keratinised

Question 5

Explain briefly, the structure of connective tissue

Answer 5

Ordered fibre system with proteoglycans and glycosaminoglycans which all help to maintain tissue turgidity and integrity. Weak hemi-desmosomes between tooth and gingiva to reinforce the tissue.

Question 6

During disease, what happens to the structure of the epithelium and what starts to form?

Answer 6

Highly organised structure disappears.
The JE and SE start to adopt features of the OE - rete pegs and keratinisation
Dense infiltration of immune cells into the tissue

Question 7

Name the 4 stages of the lesions towards periodontal disease

Answer 7

1 - Initial Lesion (24-48h). Localised to gingival sulcus and subsequent periodontal tissue. Complement, fibrin, increase in GCF, few lymphocytes.

2 - Early lesion (4-7 days). Localised proliferation of junctional epithelium and sulcular epithelium. Greater increase in GCF flow rate. Local accumulation of T cells.

3 - Established Lesion (2-3 weeks). Proliferation of JE and SE, further loss of collagen within the gingiva, new vessel formation, maximal increase in GCF, T cells may dominate lesion

4 - Advanced Lesion (PERIODONTITIS). Collagen destruction within the periodontal ligament and bone loss. GCF, IgG, IgA, IgM, complement. Dense infiltration of lymphocytes, plasma cells and macrophages.

Question 8

What is complement and how does that work?

Answer 8

20 proteins in a cascade process. All pathways result in the formation of C3 which eventually leads to formation of MAC. MAC then punches holes in the bacterial plasma membrane.

Question 9

What are the main roles of macrophages?

Answer 9

• Present antigens to T cells to promote adaptive immune responses
• Receptors for LPS
• Express TLR4 to recognise gram negative organisms
• Phagocytosis

Question 10

Explain briefly what cytokines are

Answer 10

• Small molecular weight proteins that undergo rapid action
• Rapidly degraded
• Receptor mediated action
• Cytokines operate locally, some with both local and systemic affects

Question 11

What are the main roles of antibodies?

Answer 11

Neutralisation - antibodies bind to toxins and neutralise
Opsonisation - antibodies binding to antigen to allow a macrophage to recognise them more effectively
Complement - immune complexes can activate complement

Question 12

Which cells can undergo antigen processing?

Answer 12

• Dendritic cells
• Macrophages
• B lymphocytes