A Johns Hopkins researcher described part of the body?s immune response as being like “trying on” different parts of a microbe to find the best fit.
A protein called DM helps these cells ignore viral fragments that won?t contribute to a kill, said Dr. Scheherazade Sadegh-Nasseri, associate professor of pathology, biophysics and biophysical chemistry.
“We?ve known about this protein for about 10 years, but not how it works,” she said. Under a microscope, Sadegh-Nasseri watches the protein kick off unacceptable fragments of the helper cells until a proper fit is made. Once that happens, the DM protein no longer recognizes the bond between viral DNA and the helper cell.
A report on her team?s work appears in the January edition of Nature Immunology.
The helper cells break down viruses and other pathogens, then look for pieces ? antigens ? they can recognize, Sadegh-Nasseri said. Once they find their match, they pass the information on to Helper T cells, which produce antibodies to kill the pathogen.
Researchers long have known the immune system needs the “assistant” protein DM so the anti-infectious attack can begin, according to information from Hopkins. Cells missing DM can?t do this at all.
In experiments measuring the length of time an antigen stays stuck, they found DM makes sure a cell holds onto a microbe long enough to catch the attention of immune cells in the first place.
Cells with DM normally hold on for six days, long enough for symptoms like sniffles and fever to develop.
When they removed DM from normal cells, the cells did not bond with the flu antigen.
