Background: Invariant natural killer cells (iNKT) are an important immunoregulatory T cell subset. Currently several flow cytometry-based approaches exist for the identification of iNKT cells, which rely on using the 6B11 monoclonal antibody or a combination of anti-Valpha24 and anti-Vbeta11 antibodies.
Objective: The aim of this study was to compare the ability of two flow cytometry-based methods for detecting the frequency of circulating iNKT cells.
Methods: The frequency of iNKT cells was detected in the peripheral blood of 37 healthy adult donors by flow cytometry using the 6B11 antibody or a combination of anti-Valpha24 and anti-Vbeta11 antibodies.
Results: The frequency of iNKT cells detected by 6B11 antibody or by combination of anti-Valpha24 and anti-Vbeta11 antibodies was significantly different (0.54% vs. 0.31%, respectively, p<0.001) but the values were highly correlated (Spearman r = 0.742, p<0.0001).
Conclusion: The results of this study indicate that different combinations of mAbs detect different frequencies of peripheral blood iNKT cells and a consensus in the field needs to be established to allow better assessment of iNKT-related studies and suggest using different methods for accurate identification of iNKT cells.