Frequently Asked Questions

Often we receive questions from our customers. Therefore, we decided to answer the most common questions here.

If you still do not manage to find an answer to your question, please do not hesitate to contact us.

How should allergens be stored?

After receiving the products they should be stored frozen in a freezer, at -20ºC.

How should I store the products after I dissolved them with a PBS buffer?

We do not recommend to store the solution with PBS at -20ºC. By using PBS as a buffer and storing at -20ºC you will create phosphate acid and phosphate acid can damage the proteins. If you are going to use PBS buffer, you can store it in a refrigerator at 2-8ºC. The time you can store it depends on the quality of your PBS and how sterile you are working. If you really want to freeze the solution we recommend to use 0.9% NaCl. In general, we recommend to freeze-thaw your material as little as possible. Find out more here.


How can I order your products?

You can place an order by sending us an e-mail or by giving us a call. Read more here.

At what temperature do you ship your products

All of our products can be shipped at room (ambient) temperature and will be delivered in freeze-dried form. The freeze-dried material will remain stable and will not lose its potency during transport. We have performed long term stability studies at -20°C and short term stability studies at ambient temperature (transport). Read more about the stability during transport on this page.

What is the difference between a whole culture and mite bodies?

A freeze dried Whole culture (.60) consists of mites, mite parts, faecal particles and growth medium (ratio Der p 1/Der p 2 is 10:1).  Consequently, downstream processing results in a freeze dried product. Thus, an extract freeze dried has higher Der p 1 and Der p 2 concentrations than a Whole culture.

Freeze dried mite bodies (.30) consists only, at least for 95%, of mite bodies (ratio Der p 1/Der p 2 is 1:1). Downstream processing of mite bodies results in a freeze dried product which has higher Der p 1 and Der p 2 concentrations than mite bodies (.30).

In conclusion, it is simply a question of quantities and ratios of Der p 1/Der p 2 in Whole cultures (.60) and mite bodies (.30).

I am using your biotinylated HDM products. Do you have a protocol for the use of these biotinylated products?

Yes, you can read further instructions on this page.

What kind of medium do you use in producing your mite cultures which give the mite allergens?

In our production process we do not add any proteins. The only compound we use in our products which is not strictly from mites is the medium where the mites feed on. This medium contains an absolute low number of non-mite proteins and these concentrations will not interfere with your process.

Can I re-order material from a specific LOT/ batch?

We understand that if you are using source material which is fulfilling your requirements, you would like to receive the same material again for future projects. In order to provide material from the same batch over a longer period of time, we produce large batches so you don’t have to worry about receiving different material each time you place an order. If you are using our material and you are satisfied with it. you can even place a reservation of a specific LOT so you will receive the same material in the future. This way you don’t have to test a new batch, which will save you time and money!

Can you deliver excrements of the house dust mites?

We can deliver excrements of D. pteronyssinus and D. farinae. The main source of house dust mite allergy is excrements and we have  collected the excrements. Please contact us for more information.

Why is it important to work with purified allergens rather than allergen extracts?

Purified allergens gives a defined product. The House dust mite extract contains a total mixture of proteins with proteins which don’t give an allergic reaction. With a defined mixture the disadvantage could be that some allergens are not available, although the defined allergens e.g. Der p 1 and Der p 2 give a reaction in a mouse model comparable to the HDM extract.

What is the difference between the forms you offer?

.30: Mite bodies: purified mite bodies, this does not contain other material such as the faeces of the mites. Delivered in total dry weight.
.40: Semi-purified mite bodies: semi-purified mite bodies. Less purified then the .30. Delivered in total dry weight.
.60: Whole culture: A whole culture consist of all the material of the house dust mite cultivation. This means: mite bodies, eggs, larves, cultivation medium and the faeces. Delivered in total dry weight.
.64: Extract with low level of endotoxin: the same as our regular .85 extract but with a low level of endotoxin. Delivered in total dry weight. We only have this product available of the D. pteronyssinus mite.
.71: purified Group 1 allergen (Der p 1 or Der f 1). Based on protein content (BCA).
.72: purified Group 2 allergen (Der p 2 or Der f 2). Based on protein content (BCA).
.85: Extract (of whole culture): the whole culture which is extracted. A whole culture consist of all the materials of the cultivation, including bodies, eggs, larvae, skin parts, cultivation medium and the excrements. This is the regular extract which is the most used by researchers. Delivered in total dry weight.
.86: Extract (of mite bodies): purified mite bodies which is extracted, this does not contain other material such as the faeces of the mites. Delivered in total dry weight.
.87: Excrements: the purified excrements (faeces/ droppings) of the house dust mites. We have excrement extracts available from D. farinae and D. pteronyssinus. Delivered in total dry weight.
.95: Extract: Regular HDM extract but not filled out on dry weight but on protein content (BCA). These are small vials which are developed for researchers.

In what form do you deliver your products?

Our material will be delivered in freeze-dried (lyophilized) form. You can simply weigh the amount you need, dissolve the freeze-dried product in your buffer of choice and analyse your product. The released product can be used nearly immediately. Read more here.

How long can I store your products?

The storage time depends on the production date and type of products. Most of our allergens can be stored for approximately 5 years in a -20ºC freezer.

Do you ship the products worldwide?

Yes, we can ship our products worldwide. We are using FedEx as our carrier. Read more here.

Can we use your raw materials as an active pharmaceutical ingredient (API) starting materials?

Our whole cultures as well as the mite bodies are active pharmaceutical ingredient (API) starting materials. This means that these materials can be used for further processing, such as extraction procedures under GMP pharmaceutical requirements, for example, by allergen vaccine producers and diagnostic companies. The responsibility for the extraction procedure under GMP lies with our clients. Our quality systems incorporate the important aspects of GMP standards to meet regulations and make sure that you will receive source material with the best fit to your application.

I am working with animal models. Do you have examples of models in which house dust mites (HDMs) are used?

Yes. Often we receive similar questions about house dust mite animal models from our clients. Therefore we have collected data regarding several animal models from research performed at different universities. For more information, please follow this link. Here you can find a table where you can read about different known allergic asthma protocols and their results. The overview can be used as an indication which allergic asthma protocol to use for your own research.


What buffer should I use to dissolve the products?

We recommend to use a PBS buffer.

What production process do you have for your moulds?

Citeq produces moulds with shaking incubation. The product is a result of filtration of the mycelium and spores. This filtrated medium is concentrated, dialysed and freeze-dried.  With this method the freeze dried end product, contains only products produced by the moulds. It contains no medium and no spores. Due to concentration and dialysis there is a good amount of proteins in the product available.

Are your products suitable for in-humans use and immunotherapy?

Our products are for research purposes only and will be delivered in freeze-dried (lyophilized) form. Our extracts are not suitable to be used for immunotherapy and in-human use. We produce our House dust mite products to conform the regulations source materials. For more information, exhibit Table 1, on page 7 here.

How are allergens purified?

Our allergens are purified with classical biochemical methods with columns based on different binding capacities and our last step is a size exclusion column. After this last step our products are freeze dried.

How to dissolve mould extracts

Improper reconstitution of lyophilized (freeze-dried) allergenic extracts can cause variations in allergen content of the same extract after reconstitution and should be avoided. On this page we report on the solubility of lyophilized Alternaria alternata medium extract.

Are the products dialysed before freeze-drying?

Our products will be delivered in freeze-dried (lyophilised) form. Before freeze drying the products are dialysed in a volatile buffer. This results in salt free end product. You can dissolve the product in a buffer of your choice.

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