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FAQ: PepMix™ Peptide Pools

Please refer to the corresponding frequently asked questions (FAQs) below.
If you can not find the question you are looking for, please contact our customer support team: peptide@jpt.com

What is a Pepmix™?

PepMixes™ are peptide pools generated by chemical synthesis and pooling of individual 15meric peptides overlapping by 11 amino acids, spanning entire protein antigens or of selected MHC class-I or class-II-restricted epitopes.

How much peptide is in the vial?

Each vial contains 25ug of each of the individual peptides.

Which PepMixes are available as pre-made pools?

JPT offers a continuously growing number of peptide pools. Currently, we have appr. 150 pre-made pools available. 

What do I do if my protein of interest is not available as PepMix™?

Simply send us your antigen sequence or Swiss Prot accession to receive a quote on your customized PepMix. Contact: peptide@jpt.com.

Are you also providing individual peptides and matrix pools for T cell epitope identification?

Since all pools are made from individual synthetic peptides, we offer provision of single peptides and matrix pools for custom PepMixes™ at only a little extra cost.
Simply send us your antigen sequence or Swiss Prot accession # to receive a quote on your customized PepMix.
Contact: peptide@jpt.com.

Are you offering Custom Pooling and Aliquotation service?

Yes - we recommend purchase of freeze dried pools and single peptide aliquots for enhanced stability.
Our Pooling and Aliquotation protocols are validated and certified according to DIN ISO 9001:2015 and GCLP guidelines.
We guarantee presence of all peptides, high accuracy of aliquotation and batch-to-batch reproducibility.
Please ask our customer support (peptide@jpt.com) for optimal design of your pools.

How many peptides are in a mix?

Depending on the length of an antigen, a mix can contain between 20 and several hundred peptides.

How do you ensure that the pool does not contain byproducts that cause inhibition of T-cell responses or give false positive responses?

Danger of false positive T-cell responses or inhibition of T-cell responses by toxic contaminants depend on peptide specification.
Together with its clinical collaboration partners, JPT developed synthesis and purification protocols which avoid presence of contaminants causing false positive T-cell responses or inhibition of T-cell responses by toxic byproducts to a large extent.
In addition, JPT established QC procedures ensuring a high level of batch to batch reproducibility. Positive control pools will be QC’s for chemical purity and integrity as well as biological performance.
JPT’s pooling strategy is validated and was audited to be in accordance with DIN ISO 9001:2015 and GCLP requirements.

How will PepMixes™ be delivered?

PepMixes™ will be delivered freeze dried at room temperature.

How do I store my PepMix™?

Freeze dried PepMixes™ should be stored at -20°C for long term storage.

How stable is my PepMix™?

Since PepMixes contain freeze dried peptides, stability is determined by the stability of the single peptides in the mix.
Generally, most peptides are stable over years when stored at -20°C in freeze dried state.
However, peptides containing amino acids such as Met, Cys or N-terminal Gln tend to oxidation or pyroglutamate formation.
Since kinetics of such deterioration depends on primary peptide structure, stability can hardly be predicted.
Therefore, we recommend usage of peptide pools within 6 months.
For clinical trials, we offer stability testing via our custom Pepmix program.
Avoid repeated freeze/thaw cycles of dissolved PepMixes!

How do I reconstitute my PepMix™?

The best solvent to dissolve a PepMix is DMSO, followed by slow dilution with an appropriate buffer system.
Vortexing and sonication may ease the dissolution process.
Please refer to our downloadable PepMix-protocol for details.
Please note that dissolved peptides have a limited stability.
Therefore, we recommend immediate freezing of aliquots which are not used shortly after the dissolution process.
JPT also offers freeze dried pool aliquots.

What is the maximum concentration of DMSO I can use in my T-cell assay?

DMSO is a cytotoxic reagent.
Based on literature, we recommend a maximum DMSO concentration of 1% (v/v).

What peptide concentration do you recommend for stimulation?

The recommended concentration for stimulating PBMC's is 1-2 µg of each individual peptide/ml.

Can I stimulate whole blood samples?

Although successful stimulation of whole blood samples has been described, applied concentration of peptide pool may be significantly higher compared to PBMC (peripheric blood mononuclear cells) stimulation.

What pools do you recommend for standardisation and positive controls of T-cell assays such as ELISA and CFC?

Both of our CEF pools (standard and extended) have been extensively used as positive, antigen specific control for CD8+ T cell stimulation in ELISPOT, intracellular cytokine and CTL assays.
For efficiency in vitro stimulation of antigen-specific CD4+ and CD8+ T cells, we have developed a series of CMV related PepMixes such as the pp65-pool, the IE-1 pool, the IE-2 pool and others.

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