Enhancing the Stability of Haemonchus contortus Glyceraldehyde-3-Phosphate Dehydrogenase and Binding of Host Albumin to the Parasite Enzyme.

Haemonchus contortus is an economically important parasite of domestic animals. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) excreted in the ES product of H. contortus can be a promising vaccine candidate for controlling the parasite infection. Unfortunately, the parasite enzyme breaks down rapidly. The current study focusses on stabilizing the recombinant GAPDH (rGAPDH) of H. contortus. The rGAPDH was purified and stored in two different buffers (sodium phosphate + EDTA and bicarbonate-sodium chloride) to check the stability. The affinity of the parasite enzyme towards host serum (Goat) components was evaluated by affinity chromatography. The interacting component was identified by mass spectrometry. Here, we report that the enzyme can be stabilized for at least 3 months if stored in bicarbonate-sodium chloride. This should facilitate testing of the enzyme in challenge trials. Additionally, we show that the parasite enzyme has affinity for host albumin; this interaction may have significance in host-parasite relationship. The present study reports a combination of sodium bicarbonate (0.1 M) with 0.5 M sodium chloride as a suitable buffer to enhance the stability of H. contortus GAPDH.