CD8+ T cell responses in bronchoalveolar lavage fluid and peripheral blood mononuclear cells of infants with severe primary respiratory syncytial virus infections.
A protective role for CD8+ T cells during viral infections is generally accepted, but little is known about how CD8+ T cell responses develop during primary infections in infants, their efficacy, and how memory is established after viral clearance. We studied CD8+ T cell responses in bronchoalveolar lavage (BAL) samples and blood of infants with a severe primary respiratory syncytial virus (RSV) infection. RSV-specific CD8+ T cells with an activated effector cell phenotype: CD27+CD28+CD45RO+CCR7-CD38+HLA-DR+Granzyme B+CD127- could be identified in BAL and blood. A high proportion of these CD8+ T cells proliferated and functionally responded upon in vitro stimulation with RSV Ag. Thus, despite the very young age of the patients, a robust systemic virus-specific CD8+ T cell response was elicited against a localized respiratory infection. RSV-specific T cell numbers as well as the total number of activated effector type CD8+ T cells peaked in blood around day 9-12 after the onset of primary symptoms, i.e., at the time of recovery. The lack of a correlation between RSV-specific T cell numbers and parameters of disease severity make a prominent role in immune pathology unlikely, in contrast the T cells might be involved in the recovery process.
Division of Pediatrics, Wilhelmina Children's Hospital, University Medical Center, Utrecht, The Netherlands.
Jojanneke
J
Heidema
Michaël V
MV
Lukens
Wendy W C
WW
van Maren
Mariska E A
ME
van Dijk
Henny G
HG
Otten
Adrianus J
AJ
van Vught
Desiree B M
DB
van der Werff
Sjef J P
SJ
van Gestel
Malcolm G
MG
Semple
Rosalind L
RL
Smyth
Jan L L
JL
Kimpen
Grada M
GM
van Bleek
D000954:Antigens, Surface / Q000032:analysis; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology*
D000954:Antigens, Surface