Question
A 60 yr old diabetic was admitted in the orthopaedic ward for surgical debridement for chronic osteomyelitis of foot. The patient developed fever, hypotension, confusion, rash after 3 days of admission. It was treated with antibiotics, inopressors and IV fluids. What is the likely mechanism in this case
| A. |
Binding of mannose binding protein to specific host lectin protein.
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| B. |
Increase in eosinophils.
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| C. |
Binding of IGF to mast cells.
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| D. |
Binding of superantigen to Gamma and Beta region of T-cell receptor.
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Show Answer
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Correct Answer � D
Explanation
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Binding of superantigen to Gamma and Beta region of T-cell receptor.
Superantigens directly activate T-cells without being processed by antigen presenting cells like dendritic cells.
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The variable beta region of the T-cell receptor is the receptor for superantigen.
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Because of non-specific activation of T-cells cytokines are released massively.
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Some of the important bacterial superantigens Staphylococcus are-
1)Enterotoxin,
2) Exfoliative toxin,
3) Toxic shock syndrome toxins.
Other options explanation:-
A) Binding of mannose binding protein to specific host lectin protein- this is seen in lectin pathway of complement. It is mediated through lectin proteins present on the host which interact with mannose residues present on microbial surfaces.
B) Increase in eosinophils is seen in allergic conditions and parasitic infections. Eosinophils have bilobed nucleus with granular cytoplasm.
C) Binding of IGF to mast cells- mast cells contain cytoplasmic granules which is rich in histamine. It has a major role in type 1 hypersensitivity reactions.
