Trypanosoma brucei gambiense, causative agent of West African sleeping sickness, evades the host antibody response through antigenic variation. This is mediated by switching the expression of which surface molecule?

• A Variant surface glycoprotein (VSG) ✓
• B Glycosylphosphatidylinositol (GPI) anchor
• C Procyclic acidic repetitive protein (PARP)
• D Trans-sialidase

Explanation

Trypanosoma brucei evades host immunity by antigenic variation, periodically switching expression of variant surface glycoproteins (VSGs). The parasite has a repertoire of over 1000 VSG genes. This allows waves of parasitemia and chronic infection. GPI anchors attach VSGs to the membrane but are not the variable component. Trans-sialidase is found in Trypanosoma cruzi, not T. brucei.

Reference: Jawetz, Melnick, and Adelberg's Medical Microbiology, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.