We demonstrate a precise role of AsPPase in larval molting and development and describe the potential of rAsPPase in protective immunity to A. suum infection. We show in reverse transcriptase PCR analysis that disruption of AsPPase gene function by RNA interference (RNAi) resulted in a suppression of AsPPase mRNA levels. RNAi also caused an inhibition of L3 molting (31%) and a suppression of native protein expression, as demonstrated by a 56% reduction in enzyme activity. The anatomic location of AsPPase native enzyme in the hypodermis of larvae along with its elevated expression prior to and during the molting process supports such role. Anti-rAsPPase IgG also resulted in a 57% molting inhibition of A. suum lung-stage L3 to L4 in vitro with developmental arrest. Mice immunized with rAsPPase developed high antigen-specific IgG antibody responses and were protected (>70%) against a challenged A. suum migratory phase infection. Our results establish a critical role [for] PPase in the molting and development of Ascaris roundworms and suggest its potential as a vaccine candidate against ascariasis.
(Research Team for Zoonosis, TEL +81-29-838-7749)
Reference:
- Islam et al. (2005) Infect. Immun. 73 : 1995-2004.
- Islam et al. (2005) Int. J. Parasitol. 35 : 1023-1030.
- Islam et al. (2006) Parasitology 133 : 497-508.
