Intranasal Immunization of Lambs with Serine/Threonine Phosphatase 2A against Gastrointestinal Nematodes

Abstract

b Seven 3-month-old, female, helminth-free lambs were immunized intranasally with three doses (1 mg total) of a recombinant part of the catalytic region of the serine/threonine phosphatase 2A (PP2Ar) (group 1 [G1]). In addition, four lambs were used as an adjuvant control group (G2), four as unimmunized, infected controls (G3), and four as unimmunized, uninfected controls (G4). Fifteen days after the last immunization, lambs from G1, G2, and G3 were challenged with 10,000 larval stage 3 (L3) organisms in a plurispecific nematode infection composed of ca. 40% Trichostrongylus colubriformis, 40% Haemonchus contortus, and 20% Teladorsagia circumcincta. All the lambs were clinically monitored throughout the experiment. Parasitological (fecal egg output and immunological response), biopathological (packed-cell volume and leukocyte and eosinophil counts), and zootechnical (live-weight gain) analyses were conducted. On day 105 of the experiment, all the animals were slaughtered and the adult worm population in their abomasa examined. Intranasal administration of PP2Ar with bacterial walls as an adjuvant elicited a strong immune response in the immunized lambs, as evidenced by their humoral immune response. Immunized animals and animals receiving the adjuvant shed significantly (P < 0.001) fewer numbers of parasites' eggs in their feces. The immunization significantly reduced the helminth burden in the abomasa by the end of the experiment (>68%), protection being provided against both Haemonchus and Teladorsagia. Live-weight gain in the immunized lambs was similar to that in the uninfected controls versus the infected or adjuvanted animal groups. Our results suggest that heterologous immunization of ruminants by intranasal administration may be efficacious in the struggle to control gastrointestinal helminths in these livestock.

Self-adjuvanting C18 lipid vinil sulfone-PP2A vaccine: study of the induced immunomodulation against Trichuris muris infection

“…This confirms the high immunogenicity of the PP2A where the immunoprotective capability of the recombinant peptide was corroborated for A. costaricensis [28] as well as other nematodes such as Haemonchus contortus and Teladorsagia circumcincta [9] . The results presented reinforce the notion that conjugated lipopeptides are excellent adjuvants.…”

“…Recombinant production was previously described by Fawzi et al . [ 9 ] and briefly described below. The protein expression in the recombinant bacteria was induced with 0.5 mM IPTG (isopropyl-β- d -thiogalactopyranoside).…”

“…Unstained replicas were transferred to 0.2 µm PVDF membranes (Bio-Rad, 170-4156) using a Bio-Rad Trans-Blot Turbo TM (0.6 Å, 25 V, 40 min). Western blot analyses were carried out using sera obtained from mice immunized with PP2A [ 9 ] and diluted 1 : 150 with PBS-T (0.3% tween-20 in PBS). Membranes were washed with phosphate-buffered saline with 0.05% Tween 20 (PBS-T), incubated for 2 h at 37°C with 1 : 1000 polyclonal Goat anti-Mouse Immunoglobulins/HRP (Dako Cytomation-P0447) and developed using chemiluminescence (ClarityTM Western ECL Substrate, Bio-Rad, 170-5060).…”

“…Thus, there is an urgent need to develop new measures to control helminth infections, such as vaccinations [6][7][8]. We have previously demonstrated that the catalytic region of the enzyme serine/threonine phosphatase 2A (PP2A), which is highly conserved among a large number of nematode species [9], is capable of inducing partial levels of protection against infections by diverse parasitic nematodes when administered by the mucosal route, specifically intranasally, in mice and lambs.…”

Soil-Transmitted Helminth Vaccines: Are We Getting Closer?

“…The immunized mice also developed a combined Th17/Th9 response orchestrated by the cytokines IL-25, IL-17, and IL-9 ( 277 ). The same vaccine candidate has also been tested in lambs and was found to provide significant protection against the ovine helminth Haemonchus contortus and Teladorsagia circumcincta infection ( 286 ).…”