Frequently Asked Questions

General Information

Product Information

Pro5® MHC Class I Pentamers

ProM1® MHC Class II Monomers and ProT2® Class II Tetramers

CD1d Tetramers

Custom Peptides


How can I place an order?

Orders can be placed in several ways:

Order online via the ProImmune.website – you can pay via card or credit account

Request a quote  from the ProImmune website, you can then order via the link in the quote

Send a Purchase Order by email to enquiries@www.proimmune.com.

Order by phone: USA and Canada: +1 888 505 7765; Asia Pacific: Phone / WhatsApp: +65 8338 1853, Europe and rest of the World: +44 870 042 7279

How long does delivery take after ordering?

Catalog items (multimers, matched peptides, antibodies) are usually shipped within 1-2 weeks, many popular items will ship within 1-2 business days of receiving your order.

Custom synthesized MHC Class I-peptide Pentamer and Monomer complexes are available approximately 6 weeks from ordering. For further information click here

Custom synthesized MHC Class II Tetramer and Monomer complexes are available approximately 7 weeks from ordering.

Custom peptides take a minimum of 4 weeks for synthesis, although Specialist Fast Track synthesis (from 1.5 weeks) is also available – please contact us for more information.  PEPscreen peptide libraries are usually available for shipping within 3 weeks of an order.

Please contact us for further information.

Is there an additional charge for custom reagents?

For Class I MHC reagents, custom items are usually subject to a small set-up charge, which is  applied the first time each item is ordered. For academic customers we are pleased to waive this charge – please contact us for a quote. The set-up charge will not be applied to repeat orders of the same specificity. For further information click here.

For Class II MHC reagents (Tetramers and Monomers), there is no additional setup charge.

Who are ProImmune’s distributors?

ProImmune sells products directly in most countries. For information on distributors, please see the Distributors page on our website.

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 Product Information

How should products be stored, and how long is the guarantee period?

See below for recommended storage temperatures and guarantee periods for different products. Fluorescently labelled reagents should NOT be frozen and prolonged exposure to light should be avoided. Unlabeled reagents should be aliquoted and stored frozen; avoid multiple freeze-thaw cycles.

ProductStorage ConditionsGuarantee Period
Pro5© Class I Pentamers (labeled)4 C6 months
Pro5© Class I Pentamers (unlabeled)-80 C12 months
ProM1? Class I Monomers-80 C12 months
ProM2© Class II Monomers-80 C12 months
ProT2© Class II Tetramers4 C6 months
CD1d Tetramers4 C6 months
MR1 Tetramers4 C6 months
Antibodies4 C6 months
ProMix? Peptides-20 C6 months

Custom peptides are shipped as a lyophilised powder and should be stored at -20 C or -80 C on receipt.

What is the minimum affinity for peptides used in Custom Class I Pentamer or Class II Monomer/Tetramer synthesis?

As a general rule it is only possible to synthesize recombinant MHC complexes where the peptide has a medium to high affinity for the MHC allele. Although we do not exclusively rely on predictive algorithms, in our experience decisions based on binding affinities determined via these methods correlate well with the outcome of synthesis of custom MHC-peptide complexes.

For Class I custom synthesis , we advise our customers to use the SYFPEITHI algorithm to score their peptides www.syfpeithi.de. We will typically only proceed with a custom synthesis for peptides scoring 21 or above. However we are prepared to evaluate the synthesis of MHC-peptide complexes that yield a score of 20 or lower if other conclusive binding data are available. If scoring with SYFPEITHI is not available for your allele of choice please contact us.

For Class II Tetramer custom synthesis, the ProImmune team can assist with assessment of likely binding of MHC-peptide complexes being formed. We can also accept orders on the basis of experimental data, where for instance a pasticular specificity has been made as a multimer previously.

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Pro5© MHC Class I Pentamers

What is the concentration of Pentamers?

Our MHC Pentamers are sold as test quantities in PBS containing 1% BSA and 0.025% sodium azide. One test is sufficient material to stain 1–2 x 106 antigen-specific T cells. Labeled Pro5® MHC Pentamers are provided at a concentration of 0.05 mg/ml or 10µl/test. Unlabeled Pentamers are supplied at 0.5 mg/ml or 2µl/test.

Who provides the peptide for custom Pentamer synthesis, ProImmune or the customer?

ProImmune provides all peptides for the synthesis of Pro5® MHC Pentamers for quality control reasons. The cost of the peptide is included in the Pentamer list price.

How are Pentamers purified and what QC steps are carried out?

Every Pro5® Pentamer we ship has passed standard biochemical characterization plus two rounds of protein purification to homogeneity. This ensures that all ProImmune Pentamers are synthesized to the highest possible standard. We also test batches of Pentamer by flow cytometry to ensure they are within acceptable limits of non-specific staining.

Can empty Pentamers be synthesized?

Empty MHC class I molecules are extremely unstable. It is therefore not possible to supply customers with ‘empty’ MHC molecules. However, you can purchase an HLA-A*0201 negative control Pentamer that is assembled with an irrelevant peptide antigen that is known to have no T cell response. For other alleles, the ProImmune team can help you to select an appropriate specificity for use as an isotype control (see below).

What can I use as an isotype control for Pentamer staining?

You should use another Pentamer, either of the same allelic restriction but containing a mis-matched peptide, or a mis-matched allele and mis-matched peptide combination. It is important, however, to ensure that your donor is serologically negative for this allele/peptide combination before using it as an isotype control – the ProImmune team can assist with this.

Which antibodies do you recommend to be used with Pentamers?

ProImmune sells a range of human and mouse antibodies that we recommend for use with our Pentamers. All of these antibodies have been tested alongside Pentamer staining to ensure compatibility. For anti-CD8 staining we recommend clones LT8 for human Pentamers and KT15 for murine Pentamers. If you would like to know about alternative suitable clones, please contact us.

Do you have plans to produce rat, HLA-G or other unusual alleles?

At ProImmune we are keen to follow the specific needs of our customers. We now have available Mamu-A*01 and Mamu-A*02. View the full list of alleles available for custom synthesis. If you require the synthesis of alternative MHC molecules please contact us to express your interest.

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ProM1® MHC Class II Monomers and ProT2® ClassII Tetramers

Who provides the peptide for custom synthesis, ProImmune or the customer?

ProImmune provides all peptides for the synthesis of ProM2® Class II Monomers and ProT2® Class II Tetramers for quality control reasons. The cost of the peptide is included in the list price.

Can ProImmune synthesize empty MHC Class II reagents?

Empty MHC class II molecules are extremely unstable. It is therefore not possible to supply customers with ‘empty’ MHC molecules. However, you can purchase the reagents with CLIP peptide for all alleles.

What can I use as an isotype control for Class II staining?

Tetramer or Monomer loaded with CLIP peptide (see above) can be used for this purpose. Alternatively, an allele-mismatched reagent, or a specificity to which the sample in question is not reactive can be used.

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 CD1d Tetramers

What should I use as a negative control?

ProImmune supplies a CD1d tetramer negative control.

Do the human CD1d tetramers cross react with any other species?

The human CD1d tetramers will also cross react with non-human primates such as rhesus macaque monkey samples. The tetramers should be used following the same protocol as for human samples. For further information click here.

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 Custom Peptides

How should I dissolve peptides?

The most appropriate solvent for your peptide will depend on the peptide sequence and the peptide application. For applications involving cell culture experiments, care should be taken to ensure DMSO concentration is below 0.1% I nthe final reaction buffer. For further information click here.

How long will peptides be stable once dissolved?

Peptides containing some residues (C, M and W) will only be stable for a week or two stored at -80°C once dissolved as they are prone to oxidation. Other peptides will be stable for several months stored at -80°C. Avoid freeze-thawing cycles as this will destabilise the peptide.

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