RESUMO
Fetal/Neonatal immune responses are generally considered to be immature and weaker than in adults. We have sudied the cord blood T-cells of newborns congenitally-infected whith Tripanosoma cruzi, the protozoan agent of Chagas' disease. Our data demonstrate a predominant activation of CD8 T-cells expressing activation markers and armed to mediate effector functions. Indeed, we have detected parasite-specific CD8 T-cells secreting interferon-ã. Such response is enchanced in the presence of rIL-15. These findings point out that the fetal immune system is more competent than previously appreciated, since fetuses exposed to live pathogens are able to develop an adult-like immune CD8 T-cell response.
Assuntos
Humanos , Animais , Recém-Nascido , /imunologia , Feto/imunologia , Trypanosoma cruzi , Apoptose , Diferenciação Celular/imunologia , Citocinas/análise , Citometria de Fluxo , Sangue Fetal/citologia , Sangue Fetal/imunologia , Sangue Fetal/parasitologia , Imunidade Celular , Interferon-alfa/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Trypanosoma cruzi/imunologiaRESUMO
We report the first complete nucleotide sequence of an adult T cell leukaemia virus/human T cell leukaemia virus type I (ATLV/HTLV) isolate from a British patient of Caribbean origin. Sequence comparisons of our proviral clone (HS-35) with other molecular clones are shown. We note the strong sequence conservation between isolates of Caribbean and Japanese origin (2.3 percent divergence), but demonstrate the higher homologies existing between isolates originating from similar geographical areas (approximately 1 percent divergence). Implications for the origin, evolution and dissemination of the ATLV/HTLV-I subgroup are discussed. Analysis of defective proviral clones isolated from the same genomic library is also reported,and suggests a pattern of proviral sequence deletions during the biogenesis of defective proviruses. (AU)