WBR0346: Difference between revisions
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|MainCategory=Microbiology | |MainCategory=Microbiology | ||
|SubCategory=General Principles | |SubCategory=General Principles | ||
|MainCategory=Microbiology | |||
|MainCategory=Microbiology | |MainCategory=Microbiology | ||
|MainCategory=Microbiology | |MainCategory=Microbiology | ||
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|MainCategory=Microbiology | |MainCategory=Microbiology | ||
|SubCategory=General Principles | |SubCategory=General Principles | ||
|Prompt=A researcher | |Prompt=A researcher is studying the variability of viral envelopes and their function in viral pathogenesis. In one of his experiments, he attempts to identify viruses by the properties of their envelopes. He mixes lysates of cells infected with 5 different viral species with sheep red blood cells and obtains the grid shown below. Which of the following viruses is most likely to represent cell 4? | ||
[[Image:WBR0346.jpg|600px]] | [[Image:WBR0346.jpg|600px]] | ||
|Explanation=Hemagglutinin is a glycoprotein found on the surface of many viruses including measles, mumps, influenza, and parainfluenza. It allows the virus to bind to the tissue and determines its tropism and when examined in vitro, has the ability to agglutinate red blood cells thus the name. Not all hemagglutinins are the same. Each has a different binding target and function, they only share their ability to agglutinate red blood cells. The most studied hemagglutinin type is the inflenza virus hemagglutinin that binds to sialic acid and determines the viral strain (subtypes are named H1 through H18). | |||
|Explanation= | |||
|AnswerA=Measles virus | |AnswerA=Measles virus | ||
|AnswerAExp=The measles virus envelope contains hemagglutinin and would cause RBCs to agglutinate. | |AnswerAExp=The measles virus envelope contains hemagglutinin and would cause RBCs to agglutinate. | ||
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|AnswerE=Herpes virus | |AnswerE=Herpes virus | ||
|AnswerEExp=The herpes virus envelope lacks hemagglutinin, thus showing a lack of sheep RBC agglutination. | |AnswerEExp=The herpes virus envelope lacks hemagglutinin, thus showing a lack of sheep RBC agglutination. | ||
|EducationalObjectives=[[Hemagglutinin]], a type of [[glycoprotein]] found on the surface of many viruses including measles, mumps, influenza, and [[parainfluenza]], has the ability to agglutinate RBCs. | |||
|References=First Aid 2014 page 163 | |||
|RightAnswer=E | |RightAnswer=E | ||
|WBRKeyword= hemagglutinin, measles, mumps, influenza, parainfluenza, red blood cells, RBC, virus | |WBRKeyword=hemagglutinin, measles, mumps, influenza, parainfluenza, red blood cells, RBC, virus | ||
|Approved=No | |Approved=No | ||
}} | }} | ||
<!--Not approved because: 1. The "hemagglutination" pattern in the diagram is misleading. 2. Hemagglutination assays are used historically in the viral serology and most hemagglutination inhibition tests have been replaced by other methods for determining viral antibodies such as enzyme immunoassays (EIA).--> | <!--Not approved because: 1. The "hemagglutination" pattern in the diagram is misleading. 2. Hemagglutination assays are used historically in the viral serology and most hemagglutination inhibition tests have been replaced by other methods for determining viral antibodies such as enzyme immunoassays (EIA).--> | ||
Revision as of 17:07, 16 September 2014
| Author | [[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Alison Leibowitz)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::General Principles |
| Prompt | [[Prompt::A researcher is studying the variability of viral envelopes and their function in viral pathogenesis. In one of his experiments, he attempts to identify viruses by the properties of their envelopes. He mixes lysates of cells infected with 5 different viral species with sheep red blood cells and obtains the grid shown below. Which of the following viruses is most likely to represent cell 4?
|
| Answer A | AnswerA::Measles virus |
| Answer A Explanation | AnswerAExp::The measles virus envelope contains hemagglutinin and would cause RBCs to agglutinate. |
| Answer B | AnswerB::Mumps virus |
| Answer B Explanation | AnswerBExp::The mumps virus envelope contains hemagglutinin and would cause RBCs to agglutinate. |
| Answer C | AnswerC::Influenza virus |
| Answer C Explanation | AnswerCExp::The influenza virus envelope contains hemagglutinin and would cause RBCs to agglutinate. |
| Answer D | AnswerD::Parainfluenza virus |
| Answer D Explanation | AnswerDExp::The parainfluenza virus envelope contains hemagglutinin and would cause RBCs to agglutinate. |
| Answer E | AnswerE::Herpes virus |
| Answer E Explanation | AnswerEExp::The herpes virus envelope lacks hemagglutinin, thus showing a lack of sheep RBC agglutination. |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::Hemagglutinin is a glycoprotein found on the surface of many viruses including measles, mumps, influenza, and parainfluenza. It allows the virus to bind to the tissue and determines its tropism and when examined in vitro, has the ability to agglutinate red blood cells thus the name. Not all hemagglutinins are the same. Each has a different binding target and function, they only share their ability to agglutinate red blood cells. The most studied hemagglutinin type is the inflenza virus hemagglutinin that binds to sialic acid and determines the viral strain (subtypes are named H1 through H18). Educational Objective: Hemagglutinin, a type of glycoprotein found on the surface of many viruses including measles, mumps, influenza, and parainfluenza, has the ability to agglutinate RBCs. |
| Approved | Approved::No |
| Keyword | WBRKeyword::hemagglutinin, WBRKeyword::measles, WBRKeyword::mumps, WBRKeyword::influenza, WBRKeyword::parainfluenza, WBRKeyword::red blood cells, WBRKeyword::RBC, WBRKeyword::virus |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
