Deadly Immune Response May be Halted by Small Molecule

Through research, a team of scientists have isolated a molecule that can shut down a dysfunctional immune response that causes deadly hemorrhagic shock, resulting in delayed death of heart attack patients, promoting rejection of transplanted organs and destroying joints in patients with rheumatoid arthritis.

The results are published in a paper in Molecular Immunology.

The molecule is a modified peptide and was extracted from the protein shell of a common virus (astrovirus) that causes childhood diarrhea. The research was performed by a team at Eastern Virginia Medical School and Children’s Hospital of The King’s Daughters.

The molecule is small enough to be used in medications.

“This puts us in a position to move rapidly from in-vitro testing to in-vivo testing,” said Neel Krishna, PhD, an assistant professor of microbiology and molecular cell biology at EVMS and a pediatric virologist at CHKD, in a press release.

The molecule may help scientists one day pharmacologically modulate the complement system, which is a complex cascade of dozens of biochemical reactions that occurs on the immune system to fight of infectious disease. The complimentary system launches an attack that destroys the membranes of cells damaged by infection.

The system lays waste to cells that may have been damaged due to trauma and left without oxygen for too long, in a process known as reperfusion injury. In heart attacks, the death of heart cells during reperfusion may be irreversible and lethal. The reperfusion system is an inflammatory response and affects rheumatoid arthritis as well in a similar manner.

Previous studies have shown that the introduction of the protein shell that encase the astrovirus shuts down two of the three methods used by the complement system to destroy damaged cells, but does not shut down the system’s ability to protect from invading pathogens. This molecule was large, however, containing 787 amino acids.

The latest study, examines a smaller shard of the shell, which only contained 30 amino acids and is suitable to be used in drug therapy.