Reporting research antibody use: how to increase experimental reproducibility

Antibody information is routinely omitted from publications

Neuroscience, cancer research, regenerative medicine, infection and immunity, cell biology and cardiovascular research are just some of the fields in which research antibodies are commonly used. The sheer scale of their use is illustrated by huge sales, estimated to be worth in excess of $1.6 billion annually¹. Despite, or perhaps because of, this widespread use, it is common to hear dissatisfaction among research scientists about the quality of these antibodies. The finger of blame is often pointed at the manufacturers², yet it is questionable whether scientists themselves are doing everything they can to help the situation; surely not all problems can be placed at the door of the antibody manufacturer. One example of scientists not helping themselves is in their reporting of antibody use. There are many cases of good practice and detailed reporting, but all too frequently authors omit key details. These include the host species and code numbers, but even the source of the antibody may be left out. This makes it harder for reviewers to establish how well characterised the antibodies are and thus how reliable the data presented are likely to be. It also makes it more difficult for other researchers to accurately reproduce experiments.

Failure to report key information is not a new problem^2,3, but recent developments have increased efforts to find a solution. In particular, experimental reproducibility has been thrust into the limelight by high profile cases. For example, a study of "landmark" cancer research papers found that scientific findings from only 11% of them could be repeated⁴. Taken at face value this is a shocking statistic and, in an attempt to try to improve experimental reproducibility, the Nature Publishing Group have recently introduced a reporting checklist for life science articles⁵. This checklist highlights research antibodies as a reagent type for which reporting could be improved. A key question is: what information to provide? In this commentary we consider what information authors should be including in their publications to help improve experimental reproducibility.

Key details for reporting antibody experiments

Publications need to report core information regarding the antibodies that were used. This should include the name of the antibody, the company/academic who produced the antibody, the host species in which the antibody was raised and whether the antibody is monoclonal or polyclonal. In addition, the catalogue or clone number needs to be mentioned. This information is commonly omitted from current publications, but is important as large antibody companies will often have multiple antibodies to the same target; a unique identifier is therefore essential to allow unambiguous identification of the antibody concerned. For this reason the first step in improving reporting should be to make it mandatory for authors to include core antibody information, including a code or clone number for the antibodies they use.

A second type of information that should be reported relates to experimental details. The application the antibody was used for is of central importance. This information is normally present, but it can be hard to extract if the antibody information is listed in a ‘Materials’ section and separated from descriptions of the techniques. Having the antibody data and application data closely linked would avoid potential confusion. Furthermore, if a study uses samples from more than one species then it is also important to clearly link which antibodies were used in which species.

There are other features that could also be reported which may be particularly relevant to certain studies. For example, the antibody batch number is rarely reported, but there is evidence of variability between different antibody batches^6,7. This type of variability is likely to be a particular issue with polyclonals², but may affect monoclonals⁸. Reporting the final antibody concentration or dilution is another piece of information which can help other researchers, especially if optimisation was required during the study. Finally, it has been proposed that scientists should know the antigen which was used to raise the antibody³. This information may be commercially sensitive, but at least the location of the antigen within the protein should be known, as it will have implications for interpreting the results of certain studies. In these cases authors should be encouraged to report antigen location.

Antibody validation

The Nature Publishing Group checklist requires authors to demonstrate that every antibody used in their study has been validated for use in each of the species and specific experiments used. Validating an antibody is a complex process worthy of its own review⁹ and reporting it can be achieved in a number of ways. Supplementary information could be included to demonstrate validation by the author or a citation could be given to highlight a previous study in which the antibody was validated. Reference to the antibody validation profile from publically available databases such as 1degreebio, Antibodypedia, CiteAb or pAbmAbs could also be used. Including this information would help reviewers and other researchers accurately assess the results.

A simple format for reporting antibody information

Based on the points discussed above we would suggest researchers use the following format for reporting antibody information:

"The following antibodies were used, Mouse anti-protein A monoclonal antibody (company E, catalogue number #1000) was used for Western blotting with human cells, as validated in (figure X or reference Y or validation profile Z) and Western blotting in mouse tissue as validated in (figure X or reference Y or validation profile Z). Goat anti-protein B polyclonal antibody (company F, catalogue number #1001) was used for ELISA in human tissue as validated in (figure X or reference Y or validation profile Z) and flow cytometry in human tissue as validated in (figure X or reference Y or validation profile Z)".

This format is meant as a guide and could be adapted as required; for example, details of batch number, dilution or epitope could be added where particularly important. This information could also be usefully presented in a table if allowed by the journal. Adoption of these reporting guidelines will not eliminate researchers’ frustrations with antibodies, but should help improve experimental reproducibility and scientists’ productivity, something we all seek. An additional benefit for authors who include this information is that well annotated publications are easier for antibody companies and antibody search engines like CiteAb to highlight in their databases. This inclusion is likely to increase the number of researchers who access their work and so potentially the impact of the study.

A final thought is that journals have a big role to play in promoting good practice by including guidelines on reporting antibody details in their instructions to authors and encouraging reviewers to consider this aspect of publications when they carry out their review.