Deadly Virus Linked to Your Blood Type

(Ivanhoe Newswire) – An estimated 500,000 people worldwide die from rotavirus every year. Rotavirus is a major intestinal pathogen that is the leading cause of severe dehydration and diarrhea in infants around the world.

Some strains of rotavirus find their way into the cells of the gastrointestinal tract by recognizing antigens associated with the type A blood group – histo-blood group antigen A—  a finding that represents a new paradigm in understanding how this gut pathogen infects humans.

“The structure of a key part of a strain of the virus known as P[14] provides a clue to how the virus infects human cells,” said Dr. B. V. Venkataram Prasad, professor of biochemistry and molecular biology at Baylor College of Medicine and the report's corresponding author. In strains of rotavirus that infect animals, the top of a spike on the virus attaches to the cell via a glycan (one of many sugars linked together to form complex branched-chain structures) with a terminal molecule of sialic acid. The same did not appear to be true of virus strains that infect humans, and scientists believed the human rotavirus strains were bound to glycans with an internal sialic acid molecule, but they did not know how this occurs.

In collaboration with the laboratory of Dr. Mary Estes, professor of molecular virology and microbiology at BCM, Prasad and his colleagues found that laboratory cells modified to express the histo-blood group antigen A were easily infected by this rotavirus strain. Cells that lacked this antigen were not easily infected.
An antibody to the histo-blood group antigen A blocked infection by the virus into human intestinal cells in culture.

“Further studies identified a second rotavirus strain P[9] that uses the histo-blood group antigen as a receptor,” Prasad was quoted as saying.

The authors found humans infected with the P[14] strain had type A blood, but more studies are needed to confirm the connection.

Larger populations of infected individuals need to be studied to determine if there is a clear association of these virus strains using histo-blood group antigens as a receptor," they said.
This finding raises questions about why humans developed different blood groups, Prasad said. It may be an evolutionary change that occurred after the pathogen first invaded human cells.

SOURCE: Nature, April, 2012