Protective and Anti-Pathology Effects of Sm Fructose-1,6-Bisphosphate Aldolase-Based DNA Vaccine against Schistosoma mansoni by Changing Route of Injection

Abstract

This study aimed to evaluate the efficacy of fructose-1,6-bis phosphate aldolase (SMALDO) DNA vaccination against Schistosoma mansoni infection using different routes of injection. The SMALDO has been cloned into the eukaryotic expression vector pcDNA3.1/V5-His TOPO-TA and was used in injecting Swiss albino mice intramuscularly (IM), subcutaneously (SC), or intraperitoneally (IP) (50 µg/mouse). Mice vaccinated with non-recombinant pcDNA3.1 served as controls. Each group was immunized 4 times at weeks 0, 2, 4, and 6. Two weeks after the last booster dose, all mice groups were infected with 80 S. mansoni cercariae via tail immersion. At week 8 post-infection, animals were sacrificed for assessment of parasitological and histopathological parameters. High anti-SMALDO IgG antibody titers were detected in sera of all vaccinated groups (P<0.01) compared to the control group. Both the IP and SC vaccination routes resulted in a significant reduction in worm burden (46.2% and 28.9%, respectively, P<0.01). This was accompanied by a significant reduction in hepatic and intestinal egg counts (41.7% and 40.2%, respectively, P<0.01) in the IP group only. The number of dead eggs was significantly increased in both IP and IM groups (P<0.01). IP vaccination recorded the highest significant reduction in granuloma number and diameter (54.7% and 29.2%, respectively, P<0.01) and significant increase in dead miracidia (P<0.01). In conclusion, changing the injection route of SMALDO DNA vaccination significantly influenced the efficacy of vaccination. SMALDO DNA vaccination via IP route could be a promising protective and anti-pathology vaccine candidate against S. mansoni infection.

Comparative study of excretory–secretory proteins released by Schistosoma mansoni-resistant, susceptible and naïve Biomphalaria glabrata

“…Furthermore, nicotinamide has also been identified in the sporocysts of S. mansoni [90]. Some of these proteins, such as fructose-biphosphate aldolase, triosephosphate dehydrogenase and glucose-6-phosphate dehydrogenase have been identified as glycolytic enzymes, similar to G3PDH, which is also involved in the transition of miracidia to sporocysts [22, 91, 92]. This indicates that these proteins, or other uncharacterised proteins, may function as markers of a successful infection for other miracidia to detect, possibly decreasing their likelihood of further infection.…”

Multifunctional Fructose 1,6-Bisphosphate Aldolase as a Therapeutic Target

“…A DNA plasmid vaccine encoding S. mansoni aldolase was injected into CD1 Swiss mice intramuscularly, subcutaneously, or intraperitoneally four times at biweekly intervals ( Saber et al, 2013 ). Mice were infected with 80 cercariae 2 weeks after the last immunization.…”

Why Do Intravascular Schistosomes Coat Themselves in Glycolytic Enzymes?

“…The presence of glycolytic enzymes associated with the intravascular schistosome surface provides rationale for the many reports showing that immunization with some of these enzymes can generate protective immunity in vaccine trials . Heretofore, how an intracellular cytosolic enzyme could be a focus for a useful immunological attack was a conundrum.…”