Anti-Serpin-A9 Rabbit Polyclonal Antibody

Frequently Asked Questions

What molecular weight band should I expect for Serpin-A9 on Western blot?

Serpin-A9 migrates at approximately 46-48 kDa on SDS-PAGE, which corresponds to its 417-amino-acid sequence plus post-translational modifications. Because Serpin-A9 is a secreted glycoprotein, you may observe minor shifts depending on the extent of glycosylation in your sample type. Plasma or serum samples typically show a single sharp band near 48 kDa. If working with cell lysates, confirm secretion by comparing conditioned media to whole-cell extracts; Serpin-A9 is predominantly extracellular. Start with the recommended 1:1000 dilution and 5% BSA blocking to minimize background.

Is this Serpin-A9 antibody suitable for detecting germinal center B cells in lymphoma samples?

Yes. Serpin-A9 is also known as GCET1 and serves as a marker for germinal center-derived B cells, particularly in diffuse large B-cell lymphoma classification. This rabbit polyclonal has been validated for immunohistochemistry on human tissue, making it appropriate for DLBCL subtyping studies. Optimal dilutions for IHC typically range from 1:100 to 1:500 depending on your antigen retrieval method; citrate buffer at pH 6.0 is a standard starting point. Include reactive germinal centers from tonsil or lymph node as positive controls. Expression is nuclear and cytoplasmic in positive cells.

Does this antibody cross-react with other serpin family members?

This polyclonal was raised against a Serpin-A9-specific immunogen and has been validated for human Serpin-A9. Cross-reactivity with other serpin family members has not been systematically tested, but the serpin superfamily shares structural homology. If you are working with samples containing high concentrations of other serpins such as alpha-1-antitrypsin or antithrombin, run parallel lysates depleted of your target or use siRNA knockdown as a specificity control. The expected 46-48 kDa band should disappear or diminish significantly in knockdown samples, confirming specificity.

What is the recommended starting dilution for Western blot with this Serpin-A9 antibody?

We recommend starting at 1:1000 for Western blot, using standard conditions with 5% non-fat milk or BSA in TBST. This dilution has been validated with human cell lysates and plasma samples. Because Serpin-A9 is secreted, detection sensitivity is higher in conditioned media or serum compared to whole-cell lysates. If signal is weak, concentrate conditioned media by ultrafiltration or TCA precipitation before loading. Load 20-30 micrograms of total protein per lane as a starting point. Incubate primary antibody overnight at 4°C for optimal sensitivity.

Will this antibody detect Serpin-A9 in mouse or rat samples?

This antibody has been validated for human Serpin-A9 only. Cross-reactivity with mouse or rat orthologues is predicted but not experimentally confirmed. Human and mouse Serpin-A9 share moderate sequence identity, so cross-reactivity is possible but signal strength may be reduced. If you plan to use mouse or rat samples, run a positive control human lysate on the same blot to confirm antibody performance, and be prepared to optimize dilution or exposure time. Consider supplementing with a second antibody validated in rodent species if possible.

What sample types and lysis conditions work best for detecting Serpin-A9?

Serpin-A9 is a secreted protein, so it is most abundant in conditioned culture media, plasma, and serum. For cell lysates, use RIPA or NP-40 lysis buffer with protease inhibitors; avoid reducing conditions that might affect serpin conformation if you plan functional assays. Germinal center B-cell lines, DLBCL cell lines, and activated B cells are good positive-control sources. Plasma samples should be diluted 1:50 to 1:200 before loading to avoid overloading. Freeze-thaw cycles do not significantly affect Serpin-A9 detection, but aliquot samples to minimize repeated thawing.

How should I store this Serpin-A9 antibody and what is its shelf life?

Store the antibody at -20°C in small aliquots to avoid repeated freeze-thaw cycles, which can reduce titer and increase aggregation. The product is supplied as 100 micrograms in a stabilized formulation. Once thawed, an aliquot can be stored at 4°C for up to one month if sodium azide is present as a preservative. For long-term storage beyond one year, keep at -80°C. Do not store diluted antibody; prepare working dilutions fresh for each experiment. Typical shelf life is 12-24 months when stored properly at -20°C.

What controls should I include when using this antibody for the first time?

Include both positive and negative controls. For Western blot, use human plasma or a DLBCL cell line known to express GCET1 as a positive control; HEK293 or HeLa lysates typically show low or absent expression and serve as negative controls. For IHC, reactive germinal centers in tonsil or lymph node provide strong positive staining. A Serpin-A9 siRNA or CRISPR knockdown cell line is the most rigorous specificity control. Also run a no-primary-antibody control to assess non-specific secondary binding. Pre-immune rabbit IgG at the same concentration is an additional option.