Towards a Taenia solium cysticercosis vaccine: an epitope shared by Taeniacrassiceps and Taenia solium protects mice against experimental cysticercosis

The Taenia crassiceps recombinant antigen KETc7 has been shown to be effect ive as a vaccine against experimental murine cysticercosis, a laboratory mo del used to test potentially promising molecules against porcine Taenia sol ium cysticercosis. Based on the deduced amino acid sequence of this proline -rich polypeptide, three fragments, GK-1, GK-2, and GK-3, were chemically s ynthesized in linear form. Of the three peptides, only GK-1 inducted steril e protection against T. crassiceps cysticercosis in 40 to 70% of BALB/cAnN male mice. CK-1 is an 18-amino-acid peptide which contains at least one B-c ell epitope, as demonstrated by its ability to induce an antibody response to the peptide and T. crassiceps antigen without need of a carrier protein. Immunofluorescence studies revealed that anti-GK1 antibodies strongly reac t with the native protein in the tegument of T. crassiceps and also with an atomical structures of T. solium eggs, oncospheres, cysticercus, and tapewo rm. GK-1 also contains at least one T-cell epitope, capable of stimulating the proliferation of CD8(+) and to a lower extent CD4(+) T cells primed eit her with the free peptide or T. crassiceps total antigen. The supernatant o f the stimulated cells contained high levels of gamma interferon and low le vels of interleukin-4, Similar results were obtained with T cells tested fo r intracellular cytokine production, an indication of the peptide's capacit y to induce an inflammatory response. The remarkable protection induced by GK-1 immunization, its physicochemical properties, and its presence in all developmental stages of T. solium point to this synthetic peptide as a stro ng candidate in the construction of a synthetic vaccine against T. solium p ig cysticercosis.