Antibody & Protein FAQs

Elabscience® antibodies are provided as concentrated stocks. The optimal working concentration depends not only on the antibody concentration itself but also on the abundance of the target protein in the sample. Therefore, the recommended dilution ratios provided in the datasheet are given as a range; the final dilution ratio should be determined through pre-experiments. For assistance, please contact our technical support team for recommended starting dilution ratios.

IHC refers to immunohistochemistry. The section types generally include IHC-P (paraffin-embedded sections) and IHC-F (frozen sections).

The antibody consumption should be estimated based on the datasheet recommendations and pre-experimental results. Different samples may require different dilution ratios due to varying antigen expression levels. Example: For an IHC experiment with an optimal dilution ratio of 1:50, approximately 100 μL of diluted antibody is required per slide, which corresponds to 2 μL of undiluted antibody per slide. Therefore, 20 μL of antibody would be sufficient for approximately 10 slides.

The species listed in the datasheet have been validated and are guaranteed to work. However, we cannot guarantee that the antibody will work in unverified species, even if sequence homology is high. Whether an antibody recognizes proteins from other species depends on multiple factors and is difficult to predict. If no alternative is available and you choose to purchase an antibody for an unverified species, we recommend comparing the immunogen sequence with your target protein sequence—higher homology generally increases the likelihood of cross-reactivity. Please note that if the antibody is used in an unverified species or application, product replacement or refund may not be available.

The datasheet lists the applications for which the antibody has been validated (e.g., WB, IHC, IP, IF, etc.). If an application is not mentioned, it does not necessarily mean the antibody is unsuitable—it may indicate that we have not yet performed validation for that application, or that the validation results were suboptimal. We generally recommend that customers choose antibodies based on the validated applications and species listed in the datasheet. If you wish to try an unverified application, we suggest consulting technical support in advance or purchasing a small size for preliminary testing. Please note that if the expected results are not obtained, product replacement or refund may not be available.

Secondary antibody selection is based on two criteria: ① Primary antibody host species and isotype — For example, if the primary antibody is rabbit-derived IgG, select an anti-rabbit IgG secondary antibody (e.g., Goat Anti-Rabbit IgG); if the primary antibody is mouse-derived IgM, select an anti-mouse IgM secondary antibody (e.g., Goat Anti-Mouse IgM). ② Detection method / label — Common labels include HRP, biotin, and fluorophores. For ELISA: Biotin-labeled secondary antibodies are commonly used, followed by streptavidin-HRP for signal amplification, with TMB substrate for color development. For WB: HRP-labeled secondary antibodies are recommended, with ECL substrate for chemiluminescent detection. For IHC: HRP-labeled secondary antibodies are recommended, preferably used with an IHC detection kit (e.g., E-IR-R217 or E-IR-R220/221), with DAB substrate for color development. For IF: Fluorophore-labeled secondary antibodies (e.g., FITC, Cy3, PE) can be selected based on experimental needs, avoiding cellular autofluorescence, and detected using a fluorescence microscope.

A positive control is essential for verifying that both the antibody and the detection system are functioning correctly, and also serves as a reference to confirm the presence of the target protein in the sample. It is particularly important when the expression of the target protein in the test sample is uncertain. If no positive result is obtained, the most appropriate positive control should be selected. Most datasheets include recommended positive controls. Alternatively, databases such as SwissProt or Omnigene can be searched to identify tissues with high expression of the target protein, which can serve as suitable positive control samples.

The same protein may exhibit different molecular weights across cell types due to alternative splicing and post-translational modifications (e.g., glycosylation, ubiquitination). Therefore, the molecular weight is not fixed. UniProt provides molecular weight information for different isoforms, which may differ from the band observed in literature or on the datasheet. It is advisable to consult multiple references to confirm the expected molecular weight of your target protein in your specific sample.

Antigen retrieval can be performed using either high-pressure or microwave heating methods: ① High-pressure method: Add sufficient citrate buffer (10 mmol/L, pH 6.0) (prepared by diluting the antigen retrieval solution with ddH₂O to working concentration) to a pressure cooker and heat to boiling. Place the slides on a heat-resistant rack, immerse in the buffer, close the lid and lock the pressure valve. Maintain pressure for 4 minutes, then release the pressure valve. After the pressure returns to zero, open the lid and cool the slides at room temperature for approximately 30 minutes. ② Microwave method: Add sufficient citrate buffer (10 mmol/L, pH 6.0) to a beaker and heat to boiling. Place the slides on a heat-resistant rack, immerse in the buffer, and heat at medium-low power for 30 minutes. Cool at room temperature for approximately 30 minutes. The choice of retrieval buffer should follow the antibody datasheet recommendations. If no specific recommendation is provided: Human samples: pH 9.0 EDTA retrieval buffer is recommended (clinical samples). Mouse/Rat samples: pH 6.0 citrate retrieval buffer is recommended (research samples).

Elabscience® recombinant proteins are shipped by default in the form specified in the datasheet. If you have special requirements (e.g., requesting lyophilized protein in liquid form), feasibility depends on the specific protein. In principle, lyophilized proteins can be shipped in liquid form, but liquid proteins cannot be shipped as lyophilized powder.

Elabscience® recombinant proteins are available in liquid and lyophilized powder forms. Generally, lyophilized proteins can be shipped with ice packs, blue ice, or dry ice; liquid proteins can be shipped with blue ice or dry ice.