On 2014 Nov 13, Robert Eibl commented:

After contacting the editor in 2008 about some issues with this paper, she suggested considering a “Corrigendum”, but did not publish it. Please find below my updated and slightly modified letter to the editor:

Robert Eibl: Single-receptor adhesion measurements on living cells

Helenius et al. (1) reviewed the use of atomic force microscopy (AFM) for single-cell force spectroscopy (SCFS). They listed in table 1 the references for "receptor-ligand interactions by SCFS using living cells as probes" and pointed to two reports on cell adhesion bonds between integrin alpha4beta1 (very late antigen 4, VLA-4) and its ligand vascular cell adhesion molecule 1 (VCAM-1). Surprisingly, however, Helenius and co-workers have not included the work of Eibl and Benoit (2) in their list, although this original finding on the same integrin to ligand interaction was published well before the two cited references appeared, i.e. 5 and 18 months, respectively, earlier.

In addition to this major exclusion to the very first AFM report on VLA-4/VCAM-1 measurements at the single-molecule level on a living cell, table 1 contains two more mistakes. First, the information stated to be found in a referenced paper is actually not there: Thie et al. (3) serves as reference for the specific measurement of integrin alpha(L)beta2 (leukocyte function antigen 1, LFA-1) on its ligand interstitial cell adhesion molecule 1 (ICAM-1); these authors -- although including one of the co-authors of this review -- never claimed being able to specifically measure any cell adhesion receptor; on the contrary, they state that they could only speculate regarding the cell adhesion receptors involved in their generally unspecific measurements, which might include several integrins and other cell adhesion receptors. This error may also mislead readers with regard to several other aspects of the AFM technique for measuring leukocyte homing receptors with AFM at the single-molecule or single-receptor level, including the original developers of the approach and the time-frame in which it was developed. Second, table 1 also includes a minor, but repeated typing error: “concavalin A” instead of “concanavalin A”.

In my view, a detailed step-by-step protocol in this area could have been included at that time in the review, too (4). For readers interested in an extensive overview of this topic, a book chapter reviews this subject and includes a similar table as well as further protocols for experiments (5). Despite the discussed errors, the review includes a very useful overview on many aspects between physics and biology, and may bring the AFM technology into the scope of cell biologists, i.e. the readers of that journal. The authors are free to use their own nomenclature, like SCFS, very consistently through the review, which may appear to be useful for the beginner, but may not always be specific enough: “single-cell” measurements appear to contradict measurements between two cells, and often SCFS is also used for so-called single-molecule measurements on a cell, but a more precise nomenclature was not in the scope of the review.

REFERENCES

(1) Helenius, J., Heisenberg, C.P., Gaub, H.E., Muller, D.J. (2008). Single-cell force spectroscopy. J. Cell. Sci. 121, 1785-91

(2) Eibl, R.H. and Benoit, M. (2004). Molecular resolution of cell adhesion forces. IEE - Nanobiotechnology 151, 128-132

(3) Thie M, Röspel R, Dettmann W, Benoit M, Ludwig M, Gaub HE, Denker HW (1998). Interactions between trophoblast and uterine epithelium: monitoring of adhesive forces. Hum Reprod. (11):3211-9

(4) Eibl, R.H. and Moy V.T. (2005). Atomic force microscopy measurements of protein-ligand interactions on living cells. In: Protein-Ligand Interactions. (Editor: G.Ulrich Nienhaus), Humana Press, Totowa, NJ, U.S.A., pp. 437-448 ISBN 1588293726

(5) Eibl, R.H. (2013). Single-Molecule Studies of Integrins by AFM-Based Force Spectroscopy on Living Cells. Scanning Probe Microscopy in Nanoscience and Nanotechnology 3: 137-169, ISBN 978-3-642-25414-7_6

On 2014 Nov 13, Robert Eibl commented:

After contacting the editor in 2008 about some issues with this paper, she suggested considering a “Corrigendum”, but did not publish it. Please find below my updated and slightly modified letter to the editor:

Robert Eibl: Single-receptor adhesion measurements on living cells

Helenius et al. (1) reviewed the use of atomic force microscopy (AFM) for single-cell force spectroscopy (SCFS). They listed in table 1 the references for "receptor-ligand interactions by SCFS using living cells as probes" and pointed to two reports on cell adhesion bonds between integrin alpha4beta1 (very late antigen 4, VLA-4) and its ligand vascular cell adhesion molecule 1 (VCAM-1). Surprisingly, however, Helenius and co-workers have not included the work of Eibl and Benoit (2) in their list, although this original finding on the same integrin to ligand interaction was published well before the two cited references appeared, i.e. 5 and 18 months, respectively, earlier.

In addition to this major exclusion to the very first AFM report on VLA-4/VCAM-1 measurements at the single-molecule level on a living cell, table 1 contains two more mistakes. First, the information stated to be found in a referenced paper is actually not there: Thie et al. (3) serves as reference for the specific measurement of integrin alpha(L)beta2 (leukocyte function antigen 1, LFA-1) on its ligand interstitial cell adhesion molecule 1 (ICAM-1); these authors -- although including one of the co-authors of this review -- never claimed being able to specifically measure any cell adhesion receptor; on the contrary, they state that they could only speculate regarding the cell adhesion receptors involved in their generally unspecific measurements, which might include several integrins and other cell adhesion receptors. This error may also mislead readers with regard to several other aspects of the AFM technique for measuring leukocyte homing receptors with AFM at the single-molecule or single-receptor level, including the original developers of the approach and the time-frame in which it was developed. Second, table 1 also includes a minor, but repeated typing error: “concavalin A” instead of “concanavalin A”.

In my view, a detailed step-by-step protocol in this area could have been included at that time in the review, too (4). For readers interested in an extensive overview of this topic, a book chapter reviews this subject and includes a similar table as well as further protocols for experiments (5). Despite the discussed errors, the review includes a very useful overview on many aspects between physics and biology, and may bring the AFM technology into the scope of cell biologists, i.e. the readers of that journal. The authors are free to use their own nomenclature, like SCFS, very consistently through the review, which may appear to be useful for the beginner, but may not always be specific enough: “single-cell” measurements appear to contradict measurements between two cells, and often SCFS is also used for so-called single-molecule measurements on a cell, but a more precise nomenclature was not in the scope of the review.

REFERENCES

(1) Helenius, J., Heisenberg, C.P., Gaub, H.E., Muller, D.J. (2008). Single-cell force spectroscopy. J. Cell. Sci. 121, 1785-91

(2) Eibl, R.H. and Benoit, M. (2004). Molecular resolution of cell adhesion forces. IEE - Nanobiotechnology 151, 128-132

(3) Thie M, Röspel R, Dettmann W, Benoit M, Ludwig M, Gaub HE, Denker HW (1998). Interactions between trophoblast and uterine epithelium: monitoring of adhesive forces. Hum Reprod. (11):3211-9

(4) Eibl, R.H. and Moy V.T. (2005). Atomic force microscopy measurements of protein-ligand interactions on living cells. In: Protein-Ligand Interactions. (Editor: G.Ulrich Nienhaus), Humana Press, Totowa, NJ, U.S.A., pp. 437-448 ISBN 1588293726

(5) Eibl, R.H. (2013). Single-Molecule Studies of Integrins by AFM-Based Force Spectroscopy on Living Cells. Scanning Probe Microscopy in Nanoscience and Nanotechnology 3: 137-169, ISBN 978-3-642-25414-7_6