We read with great interest the contribution by Dr Semenov et al regarding the study entitled “Multipotent mesenchymal stem cells from human placenta: critical parameters for isolation and maintenance of stemness after isolation.” The authors implemented an outstanding study and provided a good report. However, the article contains an error in Table 2 that, I believe, may misguide the readers. The authors have erroneously characterized the Becton, Dickinson Pharmingen anti-cytokeratin 7 monoclonal antibody against epithelial antigen cytokeratin7 (CK7) to be derived from clone CAM 5.2, rather than the exact clone RCK105.

We would like to comment that BD (Becton, Dickinson and Company, Franklin Lakes, IL) has developed and manufactured both BD Pharmingen anti-cytokeratin 7 and BD Biosciences anti-cytokeratin CAM5.2 monoclonal antibodies worldwide. The former is derived from mouse immunoglobulin G1, clone RCK105, that reacts against human cytokeratin intermediate filament protein of cytokeratins 7. Whereas the latter is derived from mouse immunoglobulin G2a, clone CAM5.2, that reacts against human cytokeratin intermediate filament proteins of cytokeratins 7 and 8, respectively. Besides, Becton, Dickinson Biosciences in 1997 revised the data sheet and stated that Cam 5.2 is specific for cytokeratin 8, but to a lesser extent for CK7.

As a result, this letter can help to clarify the critical point that the BD Pharmingen anti-cytokeratin 7 monoclonal antibody is dissimilar to BD Biosciences anti-cytokeratin CAM5.2 monoclonal antibody. The BD Pharmingen anti-cytokeratin 7 monoclonal antibody (clone RCK105) should not be mistaken for BD Biosciences anti-cytokeratin CAM5.2 reagent.