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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}} {{Alison}}
|QuestionAuthor= {{SSK}} (Reviewed by Serge Korjian)
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Microbiology
|MainCategory=Microbiology
Line 8: Line 8:
|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, studying the variability of viral envelopes and their function in viral pathogenesis, 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 represented in cell 4?
|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. When examined in vitro, it 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=[[Hemagglutinin]], a type of [[glycoprotein]], is found on the surface of many viruses including measles, mumps, influenza, and [[parainfluenza]]. [[Hemagglutinin]] allows a virus to bind to tissue, determines its tropism, and when examined in vitro, has the ability to agglutinate red blood cells. Although not all [[hemagglutinin]]s are the same, each has a different binding target and function, they all are able to agglutinate red blood cells. The most studied type of [[hemagglutinin]] is the inflenza virus hemagglutinin, which binds to [[sialic acid]] and determines the viral strain (subtypes are named H1 through H18).
 
|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
 
|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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|AnswerDExp=The parainfluenza virus envelope contains hemagglutinin and would cause RBCs to agglutinate.
|AnswerDExp=The parainfluenza virus envelope contains hemagglutinin and would cause RBCs to agglutinate.
|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 shows 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=Skehel JJ, Wiley DC. Receptor binding and membrane fusion in virus entry: the influenza hemagglutinin. Annu Rev Biochem. 2000;69:531-69.
|RightAnswer=E
|RightAnswer=E
|WBRKeyword= hemagglutinin, measles, mumps, influenza, parainfluenza, red blood cells, RBC, virus
|WBRKeyword=Hemagglutinin, Measles, Mumps, Influenza, Parainfluenza, Agglutination
|Approved=No
|Approved=Yes
}}
}}
<!--Not approved because:  1. The "hemagglutination" pattern in the diagram is misleading.  2. Hemagglutination assayss 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).-->

Latest revision as of 00:15, 28 October 2020
Author [[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]]
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 shows 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. When examined in vitro, it 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.
References: Skehel JJ, Wiley DC. Receptor binding and membrane fusion in virus entry: the influenza hemagglutinin. Annu Rev Biochem. 2000;69:531-69.]]

Approved Approved::Yes
Keyword WBRKeyword::Hemagglutinin, WBRKeyword::Measles, WBRKeyword::Mumps, WBRKeyword::Influenza, WBRKeyword::Parainfluenza, WBRKeyword::Agglutination
Linked Question Linked::
Order in Linked Questions LinkedOrder::
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