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. Author manuscript; available in PMC: 2017 Apr 1.
Published in final edited form as: Cancer Immunol Res. 2016 Feb 10;4(4):323–336. doi: 10.1158/2326-6066.CIR-15-0168

Figure 1. The folate receptor is expressed in HeLa and KB cells but not in A549 cells.

Figure 1

(A) The FR-negative cell line A549 and the FR-positive cell lines HeLa and KB were tested for FR-α expression by RT-PCR., The internal control was 36B4 ribosomal RNA, present in all tumor cell lines. (B) Folate receptor expression was confirmed by immunoblot analysis in the HeLa, KB, and L1210JF cell lines. The membrane was reprobed for β actin to confirm equal loading. (C) FR expression by the A549 and L1210JF (top) and KB (bottom) cell lines was evaluated by flow cytometry using a F-IgG–FITC conjugate (200 nM, FIgG-FITC = gray histogram) or a FITC-labeled control Ab (CIgG-FITC = black histogram). As a control in the KB cell line, free folate was used to block the FR prior to labeling (bottom right panel). (D) F-IgG–FITC binding (green) to KB tumor cells was confirmed at various time points via confocal microscopy (60X magnification). Tumor sections counterstained with DAPI for nuclear identification (blue). Results shown are representative of at least three independent experiments.