Proteção imunológica contra a formação de cistos cerebrais em camundongos vacinados pela via nasal com proteínas recombinates de Toxoplasma gondii
Toxoplasma gondii is a protozoan parasite which can invade and reside in a wide range of host cells. It can infect all warm-blooded animals, including human being. Parasite invasion is associated with protein secretion from three organelles: micronemes, rhoptries and dense granules. These excreted/secreted antigens were highly immunogenic in humans and rodents, that stimulates immune humoral and cellular protection The purpose of this work was to evaluate protective activity against brain cyst formation in mice vaccinated with recombinant proteins from Toxoplasma gondii by nasal route. Rhoptry and dense granule recombinant proteins of Toxoplasma gondii (ROP2, GRA5 and GRA7) were used in vaccine preparation. For experiment, 30 Balb/C mice were divided into three groups, group 1 (G1, vaccinated challengend, n = 11) received two doses (12,5 ?g of each protein plus 0,5 ?g of choleric toxin) of recombinant vaccine, group 2 (G2, vaccinated challenged, n = 11) received two doses (buffer saline phosfato - PBS plus 0,5?g of choleric toxin) and group 3 (G3, unvaccinated challenged, n = 8) received two doses of PBS. Doses were performed at days 0 and 21. Mice were infected with 50 VEG strain brain cysts by oral infection at day 33. The G1 mice produced significantly immunoglobulin A (ELISA) after second dose of recombinant vaccine. A systemic cellular responses was observed by proliferation of splenocytes in response to recombinant proteins. Animals from G1 exhibited strong resistance to cysts formation in comparison with cholera toxin immunized groups controle (G2) and control group (G3, p<0.05). These results indicated that intranasal immunization in mice with recombinant proteins ROP2, GRA5 and GRA7 associated with cholera toxin can induce protection against tissue cysts formation after oral infection with tissue cysts of T. gondii.
Advisor:Odilon Vidotto; Odilon Vidotto [Orientador].; Italmar Teodorico Navarro; Izidoro Francisco Sartor
Source Type:Master's Thesis
Date of Publication:02/17/2006