Assuntos
COVID-19 , Viroses , Humanos , Idoso , SARS-CoV-2 , Soroconversão , Hospitais Universitários , Anticorpos AntiviraisRESUMO
Protective immunity in mice infected with Toxoplasma gondii is mainly mediated by NK cells, CD4 and CD8 T cells, and type 1 cytokines, such as gamma interferon (IFN-gamma). To clarify the roles of NK cells and IFN-gamma in protection against primary congenital toxoplasmosis, we used recombination activating gene 2 knockout (RAG-2(-/-)) mice, which lack T and B lymphocytes, in comparison with the wild-type BALB/c model. RAG-2(-/-) mice had a significantly lower risk of fetal toxoplasmosis than BALB/c mice (25 versus 63.9%; P = 0.003). This protection was associated with an increased number of maternal NK cells, IFN-gamma secretion by spleen cells, and decreased parasitemia. In the RAG-2(-/-) mice, NK cell depletion increased both the rate of fetal infection, to 56.5% (P = 0.02), and the blood parasite burden. Conversely, in the BALB/c mice, this treatment did not modify maternofetal transmission or the blood parasite burden. Neutralization of IFN-gamma in both infected RAG-2(-/-) and BALB/c mice decreased congenital Toxoplasma transmission, contrasting with an exacerbation of maternal infection. These data suggest that a partially protective immunity against congenital toxoplasmosis is achieved due to the increased number of NK cells in RAG-2(-/-) mice. However, it seems that IFN-gamma enhances, directly or indirectly, the transplacental transmission.
Assuntos
Interferon gama/biossíntese , Células Matadoras Naturais/imunologia , Toxoplasmose Animal/imunologia , Toxoplasmose Animal/transmissão , Animais , Contagem de Células , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Feminino , Transmissão Vertical de Doenças Infecciosas , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Testes de Neutralização , Gravidez , Complicações Parasitárias na Gravidez/imunologia , Toxoplasmose Animal/complicações , Toxoplasmose Congênita/etiologia , Toxoplasmose Congênita/imunologiaRESUMO
We evaluated the effect of vaccination with the SAG1 protein of Toxoplasma gondii against congenital toxoplasmosis in mice with different genetic backgrounds. In BALB/c mice (H-2(d)), vaccination reduced the number of infected fetuses by 50% and was associated with a mixed type 1 and type 2 immunity. In CBA/J mice (H-2(k)), vaccination increased the number of infected fetuses by 50% and was associated with a predominant type 2 response. Our results indicate that the effect of vaccination with SAG1 is controlled by the genetic background of the mouse.
