Delaying BCG vaccination from birth to 10 weeks of age may result in an enhanced memory CD4 T cell response.
BACKGROUND
In most tuberculosis (TB) endemic countries, bacillus Calmette-Guérin (BCG) is usually given around birth to prevent severe TB in infants. The neonatal immune system is immature. Our hypothesis was that delaying BCG vaccination from birth to 10 weeks of age would enhance the vaccine-induced immune response.


METHODS
In a randomized clinical trial, BCG was administered intradermally either at birth (n=25) or at 10 weeks of age (n=21). Ten weeks after vaccination, and at 1 year of age, vaccine-specific CD4 and CD8 T cell responses were measured with a whole blood intracellular cytokine assay.


RESULTS
Infants who received delayed BCG vaccination demonstrated higher frequencies of BCG-specific CD4 T cells, particularly polyfunctional T cells co-expressing IFN-gamma, TNF-alpha and IL-2, and most strikingly at 1 year of age.


CONCLUSIONS
Delaying BCG vaccination from birth to 10 weeks of age enhances the quantitative and qualitative BCG-specific T cell response, when measured at 1 year of age.
Kagina
Benjamin M N
BM
South African Tuberculosis Vaccine Initiative (SATVI), Institute of Infectious Diseases and Molecular Medicine and School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
Abel
Brian
B
Bowmaker
Mark
M
Scriba
Thomas J
TJ
Gelderbloem
Sebastian
S
Smit
Erica
E
Erasmus
Mzwandile
M
Nene
Nonhlanhla
N
Walzl
Gerhard
G
Black
Gillian
G
Hussey
Gregory D
GD
Hesseling
Anneke C
AC
Hanekom
Willem A
WA
D001500:BCG Vaccine / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D006801:Humans; D007115:Immunization Schedule; D007156:Immunologic Memory / Q000276:immunology*; D007223:Infant; D007231:Infant, Newborn; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D014376:Tuberculosis / Q000276:immunology / Q000517:prevention & control*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D014611:Vaccination
D001500:BCG Vaccine; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma