Effect of Antenatal and Postnatal Environment on CD4 T-cell Responses to BCG in healthy Gambian Infants

MRC Laboratories Gambia, PO Box 273, Banjul, The Gambia; National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Department of Pediatrics, Bronx Lebanon Hospital Center, 1650 Selwyn Avenue Bronx, NY10457, USA; Institute for Medical Immunology, Université Libre de Bruxelles, Charleroi, Belgium

^* To whom correspondence should be addressed. Email: djcm1{at}liverpool.ac.uk.

	Abstract

The BCG vaccine has a poor record of efficacy in low-income tropical settings. Against this background, we evaluated the immune response of infants to mycobacterial antigens over the two years following BCG vaccination at birth by measuring the IFN, IL-2 and CD154 responses of CD4 T-cells. As many cells expressed IFN in infants, 4-5 year old children and adults while CD154 was not expressed at comparable levels until the second year of infancy. The IL-2 response remained relatively low in infants, children and adults alike but correlated negatively with mother's body mass index and was highest among infants born to Mandinka mothers. Similarly, infants born in the wet season had a stronger CD154 response than those born in the dry season throughout the two years of the study. We conclude that the prenatal and perinatal environment has a lasting effect on the response of infants to the BCG vaccine.