Two-photon tissue imaging: seeing the immune system in a fresh light.
Many lymphocyte functions, such as antigen recognition, take place deep in densely populated lymphoid organs. Because direct in vivo observation was not possible, the dynamics of immune-cell interactions have been inferred or extrapolated from in vitro studies. Two-photon fluorescence excitation uses extremely brief (<1 picosecond) and intense pulses of light to 'see' directly into living tissues, to a greater depth and with less phototoxicity than conventional imaging methods. Two-photon microscopy, in combination with newly developed indicator molecules, promises to extend single-cell approaches to the in vivo setting and to reveal in detail the cellular collaborations that underlie the immune response.
Cahalan
Michael D
MD
Department of Physiology, University of California, Irvine, California 92697-4561, USA. mcalahan@uci.edu
Parker
Ian
I
Wei
Sindy H
SH
Miller
Mark J
MJ
D000818:Animals; D003952:Diagnostic Imaging / Q000379:methods*; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods*; D017785:Photons; D013601:T-Lymphocytes / Q000166:cytology*