Which brand is more suitable for expressing CHO and 293 with low IgG fetal bovine serum?

<p>For CHO-S and HEK293 recombinant antibody production, for low IgG serum, you can prioritize BI&#039;s antibody production-specific series and Gibco&#039;s low IgG series. ExCell also has a low IgG line, but you need to check the COA. The key is not to look at brand claims, but to have the supplier provide the IgG residue detection method and value for each lot. Note whether the unit is mg/100mL or μg/mL—only then is a horizontal comparison meaningful. Australian or New Zealand sources usually have more stable hemoglobin and impurities between lots than South American lots, but there is still fluctuation. With a budget of around 4000, prioritize original imported, endotoxin</p>

For the source, it is recommended to choose gamma-irradiated/sterile-filtered serum from New Zealand or Australia, but you need to ask clearly about the irradiation dose and filtration process, as some high-dose irradiation may affect CHO/293 expression. Look for manufacturers or first-tier authorized distributors, and request certificates of origin, customs declarations, batch COAs, and trial samples. If the budget is around 4,000, prioritize imported brands with domestic stock, as the lead time is more controllable. The definition of low-IgG products varies greatly among different brands, so it is best to have the distributor confirm using the testing method you care about, and do not rely only on sales verbally saying "low."

We do not recommend switching to a large batch directly. First request a trial sample and perform parallel expression using your existing CHO-S/HEK293 cells: under the same seeding density and the same feeding conditions, compare viability, doubling time, and antibody titer, then carry out a small-scale Protein A purification step to examine the elution peak and host cell protein residue. After the serum arrives, first test for endotoxin, hemoglobin, and IgG to confirm consistency with the COA. Retain samples by freezing, and wait until the trial batch and the official arrival are the same lot number before purchasing. This can reduce fluctuations in downstream purification pressure.