B Cells Detect Antigen by Spreading Membrane Over Cells
Process may help fine-tune immune response
FRIDAY, May 5 (HealthDay News) -- During an immune response, B cells stretch their cell membrane over an antigen-presenting cell and aggregate the offending proteins into a central clump, according to a report in the May 5 issue of Science. The process, termed dynamic spreading, may help fine-tune B-cell activation, the researchers suggest.
Facundo Batista, Ph.D., of London Research Institute, Cancer Research UK in London, and colleagues used scanning electron microscopy to conduct real-time imaging of the early phase of B-cell activation in culture.
The researchers found that the B-cell membrane spread over antigen-presenting cells and collected antigens. The spreading was controlled by B-cell receptor signaling and correlated with the strength of the interaction with foreign antigen. The investigators also found that the density of antigens on the presenting cell dictated the extent of cell spread.
"We propose that dynamic spreading is an important step of the immune response," the authors conclude. "The immunological synapse produced may help increase the efficiency and strength of the signal, and help discriminate against autologous proteins," according to an accompanying Perspective by Margaret M. Harnett.