The consequence of stimulating an infant's immune system prematurely (by vaccination)
is an underdeveloped - mutated receptor on the CD4 Th1 cell membrane. (An epigenetically hypomethylated area on
the surface of the CD4 Th1 cells.) The immune response in effect becomes tolerogenic instead of immunogenic and skews the
response to CD4 T helper 2 cells: Interleukin IL-4 then performs apoptosis and kills the CD4 T helper 1 cells. 

Dr Habib Zaghouani Department of Molecular Microbiology and Immunology, 
University of Missouri School of Medicine, Columbia, MO 65212, USA
PMC2787701