The transfer factor(TF) in HITF is a purely natural ingredient extracted from animal kidneys. TF mainly consists of peptides, polynucleotides and double-helix RNA. TF is a new immune booster agent, which is released by T lymphocytes. It can specifically transfer cell immunity to animals short of cell immunity and can be removed by dialysis. TF can modulate the function of B lymphocytes by acting on T lymphocytes to improve humoral immunity of animals. TF can be used to treat the diseases which can not be managed by antibiotics and immune globin.