TOWARDS A VACCINE TO PREVENT TOXOPLASMOSIS
Animal Parasitic Diseases
2012 Annual Report
1a.Objectives (from AD-416):
Develop an integrated risk model for toxoplasma in the U.S. pork industry.
1b.Approach (from AD-416):
Will test various drug or vaccine candidates in mice experimentally-infected with Toxoplasma strains of different genotypes.
This is a multi-institutional five year agreement funded through the National Institutes of Health. The main objective is to develop a protective vaccine against Toxoplasma. Mice are generally used to test the protective efficacy of vaccines because (1) mice are susceptible to Toxoplasma, (2) reagents are available to measure immune parameters in mice, and (3) mice are easily managed in the laboratory. This year we developed a robust oocyst challenge model to study protective immunity in transgenic mice human Leukocyte antigen, (HLA) and used this model to study the efficacy of adjuvants and different vaccine candidates. Entrapment of antigenic peptides in non ionic surfactant adjuvant system (NISV) has proven problematic, likely due to solubility and charge of many of these peptides. Consequently we are now moving to the use of longer proteins which will circumvent these issues. A number of these peptides that we were able to entrap in NISV were tested in the transgenic mice/oocyst challenge model. Very minimal protection was observed in these experiments. We are now moving to study immune protection using different oral delivery systems for the presentations of toxoplasma antigens.