Expression of Concern: Functional Improvement of Regulatory T Cells from Rheumatoid Arthritis Subjects Induced by Capsular Polysaccharide Glucuronoxylomannogalactan

Abstract

The corresponding author has stated that there were errors in selection of western blot images for Figs 1 and 6 as follows: - In the originally published Fig 1A, the panels for Control cells are not taken from the same replicate experiment as the panels for the RA cells. Culture supernatants were collected after 2, 18 and 72 h to test TGF-β1 and IL-10 levels by specific ELISA assays. *, p<0.05 (triplicate samples of 7 different Control and RA; RA GXMGal-treated vs untreated cells); †, p<0.05 (triplicate samples of 7 different Control and RA; RA MTX-treated vs untreated cells) (C). https://doi.org/10.1371/journal.pone.0247971.g001 - In the originally published Fig 6A, the panels for Control cells are not taken from the same replicate experiment as the panels for the RA cells. (2014) Functional Improvement of Regulatory T Cells from Rheumatoid Arthritis Subjects Induced by Capsular Polysaccharide Glucuronoxylomannogalactan.

Following publication of this article [1], concerns were raised about duplication of western blot images in Figs 1 and 6. Specifically,

- In Fig 1A the 2 h Actin panel for Control cells is a duplicate of the first three lanes of the Actin panel for Control cells in Fig 6A.

- In Fig 6B the Actin panel is incorrect and is a duplicate of the 18 h Actin panel for RA cells in Fig 6A of another PLOS ONE article [2] reporting a different experiment.

The corresponding author has stated that there were errors in selection of western blot images for Figs 1 and 6 as follows:

- In the originally published Fig 1A, the panels for Control cells are not taken from the same replicate experiment as the panels for the RA cells. A revised Fig 1 is provided in which all panels showing results for Control cells in 1A are replaced such that the revised figure shows the results for Control and RA cells from the same experiment.

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Fig 1. GXMGal effect on Treg cell response.

Activated PBMC (A and C) or purified CD4+ T cells (B) (both 5×106/ml) from Control and RA were incubated for 2, 18 and 72 h in the presence or absence (NS) of GXMGal (10 μg/ml) or MTX (10 ng/ml). After 2 and 18 h (A) or 18 h (B) of incubation, cell lysates were analyzed by western blotting. Membranes were incubated with Ab to FOXP3. Actin was used as an internal loading control. Normalization was shown as mean ± SEM of five independent experiments (A and B). *, p<0.05 (triplicate samples of 5 different Control and RA; RA treated vs untreated cells). Note that for both Control and RA cells the immunoblots at 18 h (A) share Actin loading control panels with the experiment shown in Fig 6A, as the same immunoblots were stripped and re-probed using different antibodies. Culture supernatants were collected after 2, 18 and 72 h to test TGF-β1 and IL-10 levels by specific ELISA assays. *, p<0.05 (triplicate samples of 7 different Control and RA; RA GXMGal-treated vs untreated cells); †, p<0.05 (triplicate samples of 7 different Control and RA; RA MTX-treated vs untreated cells) (C).

https://doi.org/10.1371/journal.pone.0247971.g001

- In the originally published Fig 6A, the panels for Control cells are not taken from the same replicate experiment as the panels for the RA cells. Additionally, the pSTAT3 and Actin panels for Control cells are incorrect and were taken from blots carried out at an earlier time point than stated (2 h as opposed to 18 h). In the originally

References

1. Pericolini E, Gabrielli E, Alunno A, Bartoloni Bocci E, Perito S, Chow S-K, et al. (2014) Functional Improvement of Regulatory T Cells from Rheumatoid Arthritis Subjects Induced by Capsular Polysaccharide Glucuronoxylomannogalactan. PLoS ONE 9(10): e111163. pmid:25338013

2. Pericolini E, Alunno A, Gabrielli E, Bartoloni E, Cenci E, Chow S-K, et al. (2013) The Microbial Capsular Polysaccharide Galactoxylomannan Inhibits IL-17A Production in Circulating T Cells from Rheumatoid Arthritis Patients. PLoS ONE 8(1): e53336. pmid:23308194