Question

-Once at the site of infection, phagocytosis is a chief function performed by neutrophils to neutralize the pathogen by engulfment and degradation.

i. What molecular signatures enable the neutrophils to distinguish pathogens as foreign? Provide the terms used for host patterns and foreign pathogen patterns.

ii. What group of receptors would the host cells use to recognize a mannan-coated virus?

iii. What is another group of receptors that would recognize the virus once it infiltrates the cell? What component of the innate immune system do these stimulate?

iv. It’s a really unlucky day for this patient. In addition to the virus (~100 nm diameter), some helminths (~1-2 mm) are found at the site of infection. What is the major difference in how the neutrophils would deal with the helminths compared with viruses, focusing on leukocyte effector functions?

v. A physician decides to treat this infection by prescribing, in addition to standard treatments, an inhibitor of TNF. Do you agree or disagree with the physician’s decision to prescribe the TNF inhibitor? Explain why or why not by describing the impact of the TNF inhibitor on the immune response to infection.

Answer 1

i) Neutrophils are recognize pathogens by means of the cell surface receptors which can be distinguished between host and pathogen by observing surface molecules. they are mannose receptors, LPS receprors, glucane receptor etc.

ii) PRR(Pattern recognition receptors) receptors can recognize these Pathogen-associated molecular patterns.

iii) Mononuclear phagocye system which helps to recognize the pathogens infiltrates into cells.

iv) Granulocyte-mediated immunopathology is observed in hyperre-activity during some nematode infections. The release of granule proteins can be induced through binding of antigen-IgE complexes to the high affinity IgE receptor that triggers a tightly controlled phosphorylation cascade.