1 research outputs found
In Situ Characterization of Tissue-Resident Immune Cells by MALDI Mass Spectrometry Imaging
Tissue-resident
immune cells differ from their corresponding blood
cells in many functional aspects. Although the proteome of blood immune
cells has been well-investigated, there are almost no data on tissue-resident
immune cells. Here, we explored the potential of using MALDI-TOF-MS
imaging (MSI) to investigate these cells in colon tissue, which exhibits
a strong infiltration of immune cells. MSI identified several proteinaceous
markers that colocalized with specific structures of the colon, such
as mucosa or muscularis mucosae, in six patients. In addition, we
showed that certain <i>m</i>/<i>z</i> values have
the same spatial distribution as CD3<sup>+</sup> T lymphocytes in
the lymphoid follicular structures or as CD206<sup>+</sup> macrophages
in the lamina propria. For further corroboration, blood lymphocytes
and monocytes from 10 healthy volunteers were analyzed by intact cell
mass spectrometry (ICMS). Furthermore, we analyzed monocyte-derived
macrophages that had been polarized in vitro into proinflammatory
M<sub>1</sub> and anti-inflammatory M<sub>2</sub> phenotypes. The
mass spectra differed clearly among all immune cell types. Additionally,
it was found that distinct signals from ICMS analysis were identical
to the <i>m</i>/<i>z</i> values found in the MSI
experiment in lymphoid follicular structures. These data show for
the first time that MSI is well-suited to visualize the spatial distribution
of immune cells in human colon tissue. We consider MALDI mass spectrometry
imaging to be a technique with high potential for use in rapid investigations
of tissue-specific features of cells