Induction of a protective antibody-dependent response against toxoplasmosis by in vitro excreted/secreted antigens from tachyzoites of Toxoplasma gondii.
Toxoplasma gondii is a worldwide protozoan parasite which causes severe disease in congenitally infected children and in immunocompromised patients. Besides the well-defined cytoplasmic and membrane antigens of tachyzoites, we felt that excreted/secreted antigens could play a major role in the immune response. We first report the development of a well-controlled procedure for obtaining tachyzoite excreted/secreted antigens (E/SA) in cell-free incubation media. The E/SA immunogenic in human, rat and mouse toxoplasmosis were then characterized. The major E/SA recognized by human sera from the chronic phase of toxoplasmosis had molecular weights of 108, 97, 86, 69, 60, 57, 42, 39, 28.5, 27 and 26 kD. When injected into +/+ Fischer rats, E/SA elicited high antibody titres. In addition, passive transfer of these sera to highly susceptible nu/nu littermates induced a significant degree of protection towards the virulent RH strain of T. gondii. This work, which demonstrates the key role played by E/SA in the protective immune response, suggests that these antigens should be of value both for diagnostic purposes and for the development of new strategies for immunization against toxoplasmosis.
Darcy
F
F
Centre d'Immunologie et de Biologie Parasitaire, Unité Mixte, INSERM U 167-CNRS 624, Institut Pasteur, Lille, France.
Deslee
D
D
Santoro
F
F
Charif
H
H
Auriault
C
C
Decoster
A
A
Duquesne
V
V
Capron
A
A
D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D000953:Antigens, Protozoan / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007116:Immunization, Passive; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011233:Precipitin Tests; D011817:Rabbits; D051381:Rats; D011923:Rats, Nude; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000276:immunology*; D014124:Toxoplasmosis, Animal / Q000276:immunology* / Q000517:prevention & control
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan