Antibody response in CD4-depleted mice after immunization or during early infection with Echinococcus granulosus.
The aims of this work were to investigate the existence of T-independent antigens in Echinococcus granulosus protoscoleces and to evaluate the relative contribution of T-independent stimulation to the overall antibody response in early infection. Mice depleted of CD4(+)-cells were immunized with protoscolex somatic antigens (PSA) or infected with E. granulosus protoscoleces (PSC). Results showed that the response of CD4-depleted immunized mice had the expected characteristics of a T-independent stimulation and that such T-independent stimulation was important mainly during primary response. During infection absence of CD4(+)-cells affected mainly the secretion of all IgG subclasses with the exception of IgG3 and IgM. To carry out a preliminary isolation of PSC T-independent antigens we prepared a carbohydrate enriched fraction from protoscolex antigens, using a monoclonal antibody specific for the carbohydrate moiety Gal alpha(1,4)Gal highly expressed in PSC. This fraction was mitogenic for naive mouse splenocytes and was recognized by a high percentage of the specific antibodies secreted by CD4-depleted immunized or infected mice. In summary, these results suggest that E. granulosus protoscoleces contain immunogenic T-independent antigens. Primary antibody responses to protoscolex somatic antigens and the production of IgM and IgG3 in early infection would be mainly stimulated by a T-independent mechanism.
Baz
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A
Cátedra de Inmunología, Facultad de Química, Facultad de Ciencias, Montevideo, Uruguay.
Richieri
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A
Puglia
A
A
Nieto
A
A
Dematteis
S
S
D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology*; D000947:Antigens, Helminth / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002241:Carbohydrates / Q000276:immunology; D004446:Echinococcus / Q000276:immunology*; D007114:Immunization; D008212:Lymphocyte Depletion; D051379:Mice; D008807:Mice, Inbred BALB C
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D002241:Carbohydrates