T-cells produce acidic niches in lymph nodes to suppress their own effector functions

The acidic pH of tumors profoundly inhibits effector functions of activated CD8 + T-cells. We hypothesize that this is a physiological process in immune regulation, and that it occurs within lymph nodes (LNs), which are likely acidic because of low convective flow and high glucose metabolism. Here we show by in vivo fluorescence and MR imaging, that LN paracortical zones are profoundly acidic. These acidic niches are absent in athymic Nu/Nu and lymphodepleted mice, implicating T-cells in the acidifying process. T-cell glycolysis is inhibited at the low pH observed in LNs. We show that this is due to acid inhibition of monocarboxylate transporters (MCTs), resulting in a negative feedback on glycolytic rate. Importantly, we demonstrate that this acid pH does not hinder initial activation of naïve T-cells by dendritic cells. Thus, we describe an acidic niche within the immune system, and demonstrate its physiological role in regulating T-cell activation.


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Jun 16, 2020 Data were collected on the described instruments using the built in code Data were analyzed using Excel, Prism, and Sigma Plot on both Windows and Mac platforms. Multiple versions were used. Custom code was written in MatLab for image processing of data in figures 1 G,H,I, and for steady-state modeling of Figures 2 G,H and is available upon request to corresponding author P.S.
High resolution image data are available upon request from either of the corresponding authros (PS or RJG). Data supporting all plots in Figure 1-4 are available in SOURCE DATA.

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October 2018

Life sciences study design
All studies must disclose on these points even when the disclosure is negative. Randomization was not relevant to this work. No animal experiments performed in this work required randomization.
Blinding was used in generating image quantification reported in figure 1F. Blinding was not performed for other experiments.
Antibodies used in this work are completely described in Methods, as well as Supplemental Table S3.
Multiple antibody lot numbers were used and each was validated by the flow cytometry core facility according to the manufacturer prior to used and titered for appropriate staining by us. In general, antibodies were used at a dilution of 1 ul per 100 ul staining buffer per 106 cells.
Jurkat cell was purchased from ATCC.
no authetication was performed as cells were used immediately upon receipt.

cells tested negative for mycoplasma
No commonly mis-identified cell lines were used in this study Female B6 (C57BL/6), Pmel, OT-I, OT-II and TDAG8 knockout (TDAG8 KO) mice on the C57BL/6 background were bred and housed at the Animal Research Facility of the H. Lee Moffitt Cancer Center and Research Institute (Tampa, FL). Eight-to ten-week old Balb/c, C57BL/6 and nu/nu mice (male, 22-25 g) were purchased from The Jackson Laboratory Laboratory and housed in ventilated isolette cages at 68-79 oF and 30-70% humidity with 12:12 hr light:dark cycles.
no wild animals were used in this study no field collected animals were used in this study.