WBR0484

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Immunology
Sub Category	SubCategory::General Principles
Prompt	[[Prompt::The innate immune system is characterized by a variety of cell types that act as a primary response to infection. One of the major players in the innate immune system harbors a key protective component known as major basic protein and is induced to proliferate in the presence of IL-5. Of the following cell types and functions, which best correlates with the cell described above?]]
Answer A	AnswerA::Modulate mast cell reaction
Answer A Explanation	AnswerAExp::Eosinophils are important in limiting the extent of the allergic reaction following mast cell degranulation.
Answer B	AnswerB::Mediate allergic reaction
Answer B Explanation	AnswerBExp::Mast cells and basophils are the important players in mediating allergic reactions.
Answer C	AnswerC::Scavenge damaged cells
Answer C Explanation	AnswerCExp::Phagocytes such as macrophages and dendritic cells scavenge dead cells and bacterial debris.
Answer D	AnswerD::Mediate acute inflammatory response
Answer D Explanation	AnswerDExp::The initial mediators of the acute inflammatory response include mainly neutrophils and macrophages.
Answer E	AnswerE::Produce antibodies
Answer E Explanation	AnswerEExp::Plasma cells are responsible for antibody production.
Right Answer	RightAnswer::A
Explanation	[[Explanation::Although initially considered a second line of defense only required to protect against parasites, eosinophils have been shown to be quite multifunctional and important modulators of the innate and adaptive immune response. Three major cytokines are key in regulating eosinophil development: IL-3, IL-5, and GM-CSF. Eosinophils also produce several cytotoxic proteins including major basic protein, eosinophil cationic protein, eosinophil peroxidase, and eosinophil-derived neurotoxin that can cause significant tissue dysfunction and damage. MBP is particularly important for the protection against helminth infections and is an important modulator of mast the mast cell reaction often inducing further mast cell degranulation. Educational objective: Eosinophils are important modulators of the mast cell reaction by the release of MBP. Reference: Rothenberg ME, Hogan SP. The eosinophil. Annu Rev Immunol. 2006;24(1):147-74. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::Eosinophils, WBRKeyword::IL-5, WBRKeyword::Major basic protein
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::