Select two of the T-helper subsets of CD4+ T cells and discuss their influence on the development of immune responses. (300 words)
Describe the conceptual problems Polly Matzinger identified in the classical ‘self/non-self’ model of adaptive immune activation. How did she modify this model to address conceptual problems? (150 words)
Select a vaccine of your choice and briefly discuss how this vaccine works to develop immunity against infection. (150 words)
How is antibody diversity generated and why is it important? (150 words)
Dendritic cells use a process called cross presentation to present some antigens. Describe the process of cross presentation used by dendritic cells and explain why it is necessary. (150 words)
Section B (30% weighting)
Attempt all 3 questions in this section. The total marks for this section is 30 marks. The answers should be structured to the question, accurate and with relevant information, within the word limit and supported by your research of the published literature. An accompanying reference list should be provided.
Macrophages are immune cells involved in fighting infection and are major players in the immune system. An important killing mechanism used by macrophages is the production of a radical gas called nitric oxide. Nitric oxide (NO) is derived from the guanidino nitrogen of the amino acid L-arginine and molecular oxygen in a reaction catalysed by the enzyme nitric oxide synthase (NOS). However, activation of macrophages to produce nitric oxide is highly restricted. Toll like receptors on macrophages must bind its ligand (IFN-ꝩ,LPS) to achieve induction of the NOS protein.
Why both interferon-gamma (IFN-ꝩ) and lipopolysaccharide (LPS) together produce much higher nitric oxide level than the individual treatments IFN-ꝩ and LPS given alone. ( 150 words.)
The patient experienced a Type I hypersensitivity reaction to apple on her first exposure (i.e. the first time she ate an apple). How is this possible? Within your answer you should support your reasoning, research the literature and reference to the immune mechanisms behind the reaction. (250 words.)