Karnatak PGET 2007 Microbiology MCQ Answer 2

• Antigen 5 (Ag5) is a dominant secreted component of the larval stage of Echinococcus granulosus, and is highly immunogenic in human infections.
• The antigen took its name after the work of Capron et al. , who identified a relevant precipitation line in immunoelectrophoresis experiments, designated 'arc 5', and proposed its use as a reliable marker of hydatid infection.
• Ag5 is a secreted molecule, the presence of which in hydatid cyst fluid is only evident after the larval stage of the parasite has developed the capacity to produce brood capsules and protoscoleces.
• Ag5 occurs as a major component of 67kDa and a relatively minor component of 57kDa; under reducing conditions, Ag5 consists of 38 and 22kDa subunits.
  
• The antigen is a glycoprotein containing a substantial amount of complex N-linked oligosaccharides without terminal N-acetyl-D-glucosamine residues, and lacking high-mannose carbohydrates.

Category: Karnataka PGET 2007 MCQs