Kristoffer Jarlov Jensen
|Jensen, Kristoffer Jarlov. 2014. Sex-differential Non-specific Immunological Effects of Childhood Vaccines. Bandim Health Project, Research Center for Vitamins and Vaccines, Statens Serum Institut, Department of Cardiovascular and Renal Research Institute of Molecular Medicine, Faculty of Health Sciences, University of Southern Denmarkl. 111 p.
The mechanisms behind these NSE are not fully elucidated; several distinct biological mechanisms may be involved. The present PhD project aimed to explore the immunological effects of BCG, MV and OPV. We hypothesised that the vaccines affect cellular responses to heterologous antigens and mitogens, and that the effects are different in males and females.
The investigation took advantage of three RCTs of BCG, MV and OPV, respectively, conducted by the Bandim Health Project in Guinea-Bissau, West Africa. Nested within each of these trials we conducted immunological sub-group studies of the effects of the vaccines on in vitro cytokine production, in vivo cytokine levels, blood cell distribution and other biomarkers of immune status.
In RCT 1, we investigated the immunological effects of early BCG vaccination versus the usual delayed BCG in low-birth weight infants. Four weeks after randomisation, BCG was associated with increased responses to heterologous stimulation, demonstrating a T-helper cell type-1 (Th1) polarisation, and a potentiation of monocyte-derived pro-inflammatory cytokine responses. The immunological effects of BCG tended to be more pronounced in females than males and in the dry than the rainy season.
In RCT 2, we investigated the immunological effects of early MV given at 4.5 months of age versus no early MV. Six weeks after randomisation, we found that MV was associated with higher plasma levels of MCP-1, IL-1Ra and IL-8 in females. Some of the enrolled infants had previously been included in a trial of vitamin A supplementation at birth. Post hoc analyses found that the MV effects were strongest in neonatal vitamin A supplemented infants. Vitamin A shifted the effect of MV in a pro-inflammatory direction.
In RCT 3, we investigated the immunological effects of receiving OPV plus BCG versus BCG alone at birth in normal birth weight infants. At 2-6 weeks after randomisation, co-administration of OPV with BCG reduced the IFN-γ response to PPD, confirming a previous finding. In addition, the IL-5 response to PPD was impaired. Other heterologous immune responses or activation markers were not affected, and there were no differences in the effects between males and females.