Human fetuses are able to mount an adultlike CD8 T-cell response.
Fetal/neonatal immune responses generally are considered to be immature and weaker than that of adults. We have studied the cord-blood T cells of newborns congenitally infected with Trypanosoma 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. The analysis of the T-cell receptor beta chain variable repertoire shows the oligoclonal expansion of these T lymphocytes, indicating that activation was driven by parasite antigens. Indeed, we have detected parasite-specific CD8 T cells secreting interferon-gamma after coincubation with live T cruzi. This response is enhanced in the presence of recombinant interleukin-15, which limits the T-cell spontaneous apoptosis. 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 adultlike immune CD8 T-cell response.
Hermann
Emmanuel
E
Laboratoire de Parasitologie, Faculté de Médecine and the Département de Génétique Médicale, Hôpital Erasme, Université Libre de Bruxelles, U.L.B. Route de Lennick 808, CP 616, B-1070 Brussels, Belgium.
Truyens
Carine
C
Alonso-Vega
Cristina
C
Even
Jos
J
Rodriguez
Patricia
P
Berthe
Aurélie
A
Gonzalez-Merino
Eric
E
Torrico
Faustino
F
Carlier
Yves
Y
D000818:Animals; D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D022801:Complementarity Determining Regions / Q000276:immunology; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology* / Q000469:parasitology; D005333:Fetus / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D007109:Immunity; D007231:Infant, Newborn; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D014349:Trypanosoma cruzi / Q000276:immunology
D022801:Complementarity Determining Regions; D016693:Receptors, Antigen, T-Cell, alpha-beta