Recombinant antibodies offer several key advantages compared to traditional antibodies. These include superior lot-to-lot consistency, continuous supply, and animal-free manufacturing. As such, recombinant antibodies are seeing increased use for scientific research, especially as a means of addressing the ongoing reproducibility crisis.
Traditional polyclonal and monoclonal antibodies are the product of normal B cell development and genetic recombination. They are generated by immunizing an animal with an antigen to elicit an immune response. While polyclonal antibodies are secreted by many different B cell clones and recognize multiple antigenic epitopes, monoclonals originate from a single B cell clone and are specific for just one epitope.
Recombinant antibodies are monoclonal, but their production involves in vitro genetic manipulation. After cloning the antibody genes into an expression vector, this is then transfected into an appropriate host cell line for antibody expression. Mammalian cell lines are most commonly used for recombinant antibody production, although cell lines of bacterial, yeast, or insect origin are also suitable.
Because recombinant antibody production involves sequencing the antibody light and heavy chains, it is a highly controlled and reliable process. In contrast, hybridoma-based systems for producing monoclonal antibodies are subject to genetic drift and instability, increasing the potential for lot-to-lot variability or loss of antibody expression. Recombinant antibodies are highly consistent from lot to lot, thereby ensuring reproducible experimental results.
In vitro methods for producing antibodies are amenable to large-scale production, meaning antibody availability is unlikely to become a limiting factor. Moreover, since the recombinant antibody sequence is known, continuity of supply is assured; in situations where an antibody will be used to support large, long-term studies, this can be an especially critical factor.
Unlike traditional methods for antibody production, recombinant approaches avoid the need to use animals. Where polyclonal antibodies are purified directly from the serum of the immunized host, and monoclonals are purified from either hybridoma-derived tissue culture supernatant or ascites, recombinant antibodies are instead purified from the tissue culture supernatants of transfected host cell lines. Regardless of whether an antibody is polyclonal, monoclonal or recombinant, it must always be properly validated in the intended application prior to experimental use. At CST, we adhere to the Hallmarks of Antibody Validation™, six complementary strategies for determining the specificity, sensitivity, and functionality of an antibody in any given assay. By carefully tailoring these strategies to each antibody product, we guarantee that CST antibodies will work as expected, to help you achieve results you can trust.
| Cat. # | Size | Qty. | Price |
|---|---|---|---|
| 41475S | 100 µl (50 tests) |
|
| REACTIVITY | H M R Mk |
| SENSITIVITY | Endogenous |
| MW (kDa) | |
| Source/Isotype | Rabbit IgG |
Product Information
| Application | Dilution |
|---|---|
| Flow Cytometry (Fixed/Permeabilized) | 1:50 |
All reagents required for this protocol may be efficiently purchased together in our Intracellular Flow Cytometry Kit (Methanol) #13593, or individually using the catalog numbers listed below.
NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.
NOTE: When including fluorescent cellular dyes in your experiment (including viability dyes, DNA dyes, etc.), please refer to the dye product page for the recommended protocol. Visit www.cellsignal.com for a full listing of cellular dyes validated for use in flow cytometry.
NOTE: Adherent cells or tissue should be dissociated and in single-cell suspension prior to fixation.
NOTE: Optimal centrifugation conditions will vary depending upon cell type and reagent volume. Generally, 150-300g for 1-5 minutes will be sufficient to pellet the cells.
NOTE: If using whole blood, lyse red blood cells and wash by centrifugation prior to fixation.
NOTE: Antibodies targeting CD markers or other extracellular proteins may be added prior to fixation if the epitope is disrupted by formaldehyde and/or methanol. The antibodies will remain bound to the target of interest during the fixation and permeabilization process. However, note that some fluorophores (including PE and APC) are damaged by methanol and thus should not be added prior to permeabilization. Conduct a small-scale experiment if you are unsure.
NOTE: Count cells using a hemocytometer or alternative method.
posted July 2009
revised June 2020
Protocol Id: 407
Human, Mouse, Rat, Monkey
Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues near the carboxy terminus of human histone H2A protein in which Lys119 is mono-ubiquitinated.
The nucleosome, made up of four core histone proteins (H2A, H2B, H3, and H4), is the primary building block of chromatin. Originally thought to function as a static scaffold for DNA packaging, histones have now been shown to be dynamic proteins, undergoing multiple types of posttranslational modifications, including acetylation, phosphorylation, methylation, and ubiquitination (1). Ubiquitin is a conserved 76 amino acid peptide unit that can be covalently linked to many cellular proteins by the ubiquitination process. Three components are involved in this protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thioester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (2). Histone H2A is mono-ubiquitinated at Lys119 by the Polycomb Repressor Complex 1 (PRC1) and is critical for transcriptional silencing of the developmental HOX genes and X chromosome inactivation (3-6). PRC1 is composed of Bmi1 and RING1A (also RING1 or RNF1), both of which act to enhance the E3 ubiquitin ligase activity of the catalytic subunit RING1B (also RING2 or RNF2) (3,4). Histone H2A is also mono-ubiquitinated at Lys119 at sites of DNA damage. This mono-ubiquitination event requires the PRC1 components Bmi1 and RING1B, in addition to another E3 ubiquitin ligase RNF8, and contributes to subsequent recruitment of the BRCA1 complex, via binding of RAP80/UIMC1 (ubiquitin interactive motif containing 1 protein) (7-10).
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