Abstract
This study aimed to evaluate the humoral immune response in pigs immunized intranasally and intramuscularly with recombinant Toxoplasma gondii rROP2 protein in combination with the adjuvant Iscomatrix. Twelve mixed breed pigs divided into three groups (n=4) were used, G1 received recombinant ROP2 proteins (200 µg/dose) plus Iscomatrix, G2 received PBS plus Iscomatrix, and G3 as the control group. The intranasal (IN) and intramuscular (IM) routes were used. Animals were challenged orally with VEG strain oocysts and treated on day three after challenge. Fever, anorexia, and prostration were the clinical signs observed in all animals. All the G1 animals produced antibodies above the cut-off on the day of the challenge, while the G2 and G3 remained below the cut-off. Better partial protection against parasitemia and cyst tissue formation was observed in G1 than G3. The protection factors against tissue cyst formation were 40.0% and 6.1% for G1 and G2, respectively, compared to G3. In conclusion, there were not systemic antibody responses in pigs with IN immunization with rROP2+Iscomatrix; however, after IM immunization, those animals produced higher titers than animal controls. We associated these results with partial protection obtained against parasitemia and tissue cysts formation.
Highlights
Toxoplasma gondii is a protozoan parasite that can infect all warm-blooded animals, including humans (Dubey, 1994)
The RH strain was used for PCR, and antigens for the indirect fluorescent antibody test (IFAT), and the VEG strain was used for challenging the pigs
The group 2 (G2), and group 3 (G3) groups had IgG levels just above the cut-off on day 126; the levels were lower than those seen in group 1 (G1)
Summary
Toxoplasma gondii is a protozoan parasite that can infect all warm-blooded animals, including humans (Dubey, 1994). Meat from livestock when ingested raw or undercooked is an important source of infection for humans; the risk of acquiring T. gondii infection from pork was considered higher than from other meats (Dubey, 2010). Previous studies have used live vaccines and killed vaccines to protect pigs against T. gondii cyst formation (Dubey et al, 1991, 1994; Pinckney et al, 1994; Freire et al, 2003; Kringel et al, 2004; Garcia et al, 2005; Cunha et al, 2012; Burrells et al, 2015). Live vaccines (RH and S48) carry the risk of reverting to virulence and becoming infective for humans; it is essential to produce a killed vaccine against T. gondii (Burrells et al, 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
