Characterization, cloning, and expression of two diagnostic antigens for Taenia solium tapeworm infection

Adult and larval stages of Taenia solium cause 2 diseases in humans, i.e., taeniasis and cysticercosis, respectively. Diagnosis and treatment of taeniasis are the ultimate means to eliminate cysticercosis. A serological taeniasis diagnostic test has been developed for laboratory use. However, recombinant forms of the taeniasis diagnostic proteins are required to overcome the limited supply of native proteins and allow the development of a low-cost and field-applicable test with high sensitivity and specificity. Using 2-dimensional electrophoresis of T. solium excretory and secretory (TSES) products from hamster adult tape-worm in vitro cultures, we have identified 5 T. solium-specific protein spots, with molecular weights of 33 kDa (protein isoelectrofocusing point [pI]: 5.6, 5.3, 5.1) and 38 kDa (pI: 4.6, 4.5). Protein sequencing and molecular cloning of these proteins showed that although endowed with different pls, the proteins with the same molecular weights shared the same protein backbone, named TSES33 and TSES38. Their full-length complementary DNAs encode proteins with 267 and 278 amino acids, respectively. TSES33 and TSES38 were expressed in a baculovirus system. Both recombinant proteins were recognized by a panel of taeniasis, but not cysticercosis patient serum samples, indicating that they can potentially replace the native proteins in the development of a more efficacious taeniasis diagnostic test.