In the current issue of the journal Science, the team demonstrates that antibodies can catalyze the formation of hydrogen peroxide from singlet oxygen.
All antibodies have the ability to do this," says Professors Paul Wentworth Jr., Ph.D. and Kim Janda, Ph.D., two of the lead authors on the paper. "Singlet oxygen is not something you want around."
Singlet oxygen is an electronically excited form of oxygen that forms spontaneously during normal metabolic processes or when oxygen is subjected to visible or ultraviolet light in the presence of a sensitizer. Singlet oxygen is highly reactive, making it potentially dangerous to an organism. Throughout evolution, animals have developed various mechanisms for removing singlet oxygen in order to survive. Also called immunoglobins, antibodies are produced by the immune system's B cells. The body has a large pool of B cells that recognize a wide range of foreign proteins, and after a pathogen enters the bloodstream, B cells produce specific antibodies that circulate through the blood and track down, bind to, and help eliminate the viral or bacterial invaders.
In the report, the team speculates that before this antibody-mediated immune response evolved in vertebrates hundreds of millions of years ago, an ancient form of antibodies may have existedmolecules whose role was to catalyze singlet oxygen destruction.
"Antibodies could have played a role as ancient proteins whose function was to remove singlet oxygen," says Janda.
The ability to convert oxygen into hydrogen peroxide may also be part of a previously unrecognized killing mechanism that would e
Contact: Robin B. Goldsmith
Scripps Research Institute