Preterm infants' T cell responses to inactivated poliovirus vaccine.
BACKGROUND
The antigen-specific T cell responses of preterm infants to immunization are not well understood. The aim of the present study was to compare the T cell responses of preterm infants after inactivated poliovirus vaccination with those of term infants.


METHODS
We prospectively enrolled 2-month-old preterm (gestational age, 33 weeks) and term (gestational age, 37 weeks) infants to receive 3 doses of diphtheria-tetanus toxoids-acellular pertussis-hepatitis B virus-inactivated poliovirus vaccine. Whole blood and peripheral blood mononuclear cells (PBMCs) were stimulated with poliovirus vaccine, and memory T cell activation was analyzed by flow cytometry and lymphoproliferation, respectively. Levels of poliovirus neutralizing antibodies were measured in serum.


RESULTS
We enrolled 33 preterm and 50 term infants. Preterm infants had fewer circulating CD4(+)CD45RO(+) memory (P = .005) and CD4(+)CD69(+)IFN-gamma(+) cells activated by staphylococcus enterotoxin B at 2 (P = .015) and 7 (P = .05) months of age. After immunization, preterm and term infants had comparable frequencies of poliovirus-specific CD4(+)CD45RO(+)CD69(+)IFN-gamma(+) memory T cells (P = .79). PBMCs from preterm infants had diminished poliovirus-specific lymphoproliferation (P<.001). Although all infants developed seroprotective poliovirus antibody titers, serotype 1 titers were lower among preterm infants (P = .03).


CONCLUSIONS
Preterm infants develop poliovirus-specific T cell responses that are comparable to those of term infants. However, they demonstrate nonspecific and poliovirus-specific functional T cell limitations, suggesting that investigations into whether T cell differences remain as preterm infants mature are warranted.
Klein
Nicola P
NP
Kaiser Permanente Vaccine Study Center, Oakland, California 94612, USA. Nicola.Klein@kp.org
Gans
Hayley A
HA
Sung
Phillip
P
Yasukawa
Linda L
LL
Johnson
Joanie
J
Sarafanov
Andrey
A
Chumakov
Konstantin
K
Hansen
John
J
Black
Steven
S
Dekker
Cornelia L
CL
D000914:Antibodies, Viral / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007111:Immunity, Cellular; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000276:immunology*; D008297:Male; D009000:Monocytes / Q000276:immunology; D011054:Poliovirus Vaccine, Inactivated / Q000276:immunology*; D011446:Prospective Studies; D013601:T-Lymphocytes / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000276:immunology
D000914:Antibodies, Viral; D011054:Poliovirus Vaccine, Inactivated; D018074:Vaccines, Conjugate