Immunization of newborns against viral infections may be hampered by ineffective CD8+ T cell responses. To characterize the function of CD8+ T lymphocytes in early life, we studied newborns with congenital human cytomegalovirus (HCMV) infection. We demonstrate that HCMV infection in utero leads to the expansion and the differentiation of mature HCMV-specific CD8+ T cells, which have similar characteristics to those detected in adults. High frequencies of HCMV-specific CD8+ T cells were detected by ex vivo tetramer staining as early as after 28 weeks of gestation. During the acute phase of infection, these cells had an early differentiation phenotype (CD28–CD27+CD45RO+, perforinlow), and they acquired a late differentiation phenotype (CD28–CD27-CD45RA+, perforinhigh) during the course of the infection. The differentiated cells showed potent perforin-dependent cytolytic activity and produced antiviral cytokines. The finding of a mature and functional CD8+ T cell response to HCMV suggests that the machinery required to prime such responses is in place during fetal life and could be used to immunize newborns against viral pathogens.
Arnaud Marchant, Victor Appay, Marianne van der Sande, Nicolas Dulphy, Corinne Liesnard, Michael Kidd, Steve Kaye, Olubukola Ojuola, Geraldine M.A. Gillespie, Ana L. Vargas Cuero, Vincenzo Cerundolo, Margaret Callan, Keith P.W.J. McAdam, Sarah L. Rowland-Jones, Catherine Donner, Andrew J. McMichael, Hilton Whittle
Guidelines: The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. We reserve the right to edit any letter for length, content, and clarity. Authors will be notified by e-mail if their letters were accepted. No appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editors directly at firstname.lastname@example.org.