Dendritic cells (DCs)
actively sample and present antigen to cells
of the adaptive immune system and are thus vital for successful immune
control and memory formation. Immune cell metabolism and function
are tightly interlinked, and a better understanding of this interaction
offers potential to develop immunomodulatory strategies. However,
current approaches for assessing the immune cell metabolome are often
limited by end-point measurements, may involve laborious sample preparation,
and may lack unbiased, temporal resolution of the metabolome. In this
study, we present a novel setup coupled to a secondary electrospray
ionization-high resolution mass spectrometric (SESI-HRMS) platform
allowing headspace analysis of immature and activated DCs in real-time
with minimal sample preparation and intervention, with high technical
reproducibility and potential for automation. Distinct metabolic signatures
of DCs treated with different supernatants (SNs) of bacterial cultures
were detected during real-time analyses over 6 h compared to their
respective controls (SN only). Furthermore, the technique allowed
for the detection of13C-incorporation into volatile metabolites,
opening the possibility for real-time tracing of metabolic pathways
in DCs. Moreover, differences in the metabolic profile of naïve
and activated DCs were discovered, and pathway-enrichment analysis
revealed three significantly altered pathways, including the TCA cycle,
α-linolenic acid metabolism, and valine, leucine, and isoleucine
degradation.