In the laboratory diagnosis of visceral leishmaniasis, the rK39 immunochromatographic strip test detects antibodies against a recombinant antigen derived from which part of Leishmania donovani?
- A Lipophosphoglycan (LPG) on the promastigote surface
- B A 39-amino-acid repeat unit of a kinesin-related antigen ✓
- C Kinetoplast DNA (kDNA) minicircle antigen
- D gp63 (leishmanolysin) surface metalloprotease
Correct answer: B. A 39-amino-acid repeat unit of a kinesin-related antigen
Explanation
The rK39 antigen is a recombinant protein derived from a 39-amino-acid repeat region of a kinesin-related protein found in Leishmania chagasi/donovani complex. The rK39 strip test has high sensitivity (>90%) and specificity for visceral leishmaniasis (kala-azar) and is the standard point-of-care serodiagnostic tool. LPG is a key virulence factor but not the rK39 antigen. kDNA PCR is used for molecular diagnosis. gp63 is a surface metalloprotease involved in macrophage invasion but is not the rK39 antigen.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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