Thymosin alpha-1-transformed Bifidobacterium promotes T cell proliferation and maturation in mice by oral administration

► The Tα1-transformed Bifidobacterium for oral administration was created. ► The transformed Bifidobacterium can be administrated directly without purification. ► The Tα1-transformed Bifidobacterium enhances cellular immunity through Th1 pathway. ► The Tα1-transformed Bifidobacterium induces thymus enlargement by long-time treatment.