Enhancing Mucosal-Associated Invariant T Cell Function and Expansion with Human Selective Serum

Area of Science:

• Immunology
• Cell Biology
• Cancer Immunotherapy

Background:

• Mucosal-associated invariant T (MAIT) cells are key players in innate immunity and hold promise for anti-tumor immunotherapy.
• Current MAIT cell expansion methods can lead to undesirable phenotypic changes, such as increased CD4+ MAIT cells and elevated inhibitory receptor expression, potentially impairing their function.

Purpose of the Study:

• To compare the efficacy of a novel serum replacement, Physiologix XF SR (Phx), with traditional fetal bovine serum (FBS) for expanding human MAIT cells.
• To evaluate the impact of Phx supplementation on MAIT cell proliferation, phenotype, survival, and effector functions relevant to anti-tumor immunotherapy.

Main Methods:

• Human MAIT cells were cultured in RPMI 1640 media supplemented with either Phx or FBS.
• Flow cytometry was employed to assess MAIT cell proliferation, frequency of CD4+ and PD-1+ cells, and IFN-γ production after stimulation with Escherichia coli.

Main Results:

• Phx supported significantly higher MAIT cell proliferation and survival compared to FBS.
• MAIT cells cultured with Phx exhibited a lower frequency of CD4+ and PD-1+ cells, indicating a less altered phenotype.
• Phx-cultured MAIT cells demonstrated enhanced IFN-γ production upon stimulation with E. coli, suggesting improved effector function.

Conclusions:

• Physiologix XF SR (Phx) is a superior supplement for expanding human MAIT cells compared to FBS, promoting greater proliferation and survival.
• MAIT cells expanded with Phx maintain a more favorable phenotype with lower inhibitory receptor expression and enhanced IFN-γ production.
• These findings suggest that Phx-supplemented expansion protocols yield MAIT cells with improved functional capacity for anti-tumor immunotherapy applications.