ABO blood group system B, and AB blood into type O. This is done by using glycosidase enzymes from specific bacteria to strip the blood group antigens from red blood cells. The removal of A and B antigens still does not address the problem of the Rh blood group antigen on the blood cells of Rh positive individuals, and so blood from Rh negative donors must be used. Patient trials will be conducted before the method can be relied on in live situations. Another approach to the blood antigen problem is the manufacture of artificial blood, which could act as a substitute in emergencies.
Jehovah's Witnesses and blood transfusions of outdated medical beliefs. Dissident Witnesses say the Society's use of Leviticus 17:12 to support its opposition to blood transfusions conflicts with its own teachings that Christians are not under the Mosaic law. Theologian Anthony Hoekema claims the blood prohibited in Levitical laws was not human, but animal. He cites other authors who support his view that the direction at Acts 15 to abstain from blood was intended not as an everlasting covenant but a means of maintaining a peaceful relationship between Jewish and Gentile Christians. He has described as "absurd literalism" the Witnesses' use of a scriptural prohibition on