An abstract idea, the reproduction of the mature immune system in the fight against the hepatitis B virus. Natural killer (NK) cells are essential in the early immune response against viral infections, especially by eliminating virus-infected cells. Instead, viruses have evolved multiple mechanisms to escape viral clearance mediated by NK cells.. Therefore, it is essential to understand both aspects of this cell population in the newborn. NK cells in the cord blood are thus less effective than adult NK cells in initiating cell death in their targets. Umbilical cord blood, a convenient source of cells representative of the newborn's circulation, has facilitated the comparison of newborn and adult NK cells. Given the above we can have some assumptions. Given that an adult's immune system succeeds in 90-95% of cases to cure acute hepatitis B is practically a completely different situation from the hepatitis C virus and the HIV virus. The mature immune system seems to cope with this infection with the acute hepatitis B virus. They are also deficient in ADCC, as well as in the induction of apoptosis in target cells. If a baby contacts hepatitis B with Hbe positive antigen, the chances are high that it will become chronic with this highly replicative and contagious form. Most will end up in negative Ag Hbe form. So we can assume that at the age of 2-3 years in children the maturity of nk cells is higher than in babies but still it is not mature enough to get rid of the virus and chronic form. that these medical tests for a treatment against Hepatitis B have failed every time we can look at what exactly happens when a mature person is cured of acute hepatitis B. We have absolutely everything we need but we need to reproduce the mature immune system and infected people and then one can hope for a cure as a mature immune system is cured in 95% of hepatitis B. Therapy should be with mature nk cells and tk cells and not one with antibodies. The problem is how do we do this?