Blood transfusions are a daily routine procedure in hospitals. In a day, 16k liters of blood are transfused daily in the United States. Human being has four types of blood group- A, B, AB, O. Blood type A, B have their own antigens and AB have their antigens of both A and B on their surface. Type O does not have any antigens on their surface. Blood Antigens are basically a polysaccharide on the surface of red blood cells.
The demand for blood all over the world is very high, especially during emergency surgeries and operations. Blood transfusion is only possible when the blood group of donor and recipient are matched. If they are not matched, the immune cells of the recipient will attack and destroy the RBCs of the donor.
Blood group O does not have an antigen on their surface, thus making them transfusable to any recipient of same rhesus type irrespective of the blood group. Hence, Blood group 0 are called a universal donor. However, there is a shortage of blood group O capable of meeting the huge demand.
In a breakthrough, Canadian Scientist from the University of British Columbia, Vancouver have discovered an enzyme that can cleave off the antigen from the surface of blood group A at a very low enzyme concentration. These Blood group A without antigens are basically O group that have no antigens on their surfaces. The enzyme was discovered from a bacterium, Flavonifractor plautii which they have isolated from the human gut.
The researchers first collected the gut bacteria from human feces and isolated its DNA. This DNA was chopped into many fragments and were cloned in E.coli. Those recombinant E.coli were then screen for enzymes that can digest polysaccharide from blood A antigens. To their surprise, they isolated two enzymes from a bacterium, Flavonifractor plautii that could cleave the antigens from the A group. Their work is published in Nature Microbiology.
Impacts of the discovery:
This discovery will help clinicians during an emergency when there is no time to test the blood group of the patient. Blood group O can be prepared from blood group A and stored it in the blood bank. Whenever an emergency arises, they can just transfuse the O blood to any patients.
References: Peter Rahfeld et al. Nature microbiology 4, 1475–1485(2019).