DIARECT Newsletter


Dear Madam or Sir,

The Clinical Lab Expo, with over 750 exhibitors will take place in San Diego from August 1 - 3, 2017. As in the past years, you will have the opportunity to connect with global clinical market leaders in laboratory medicine and learn about cutting-edge technologies. To learn more about the event click here. DIARECT will be attending and would like to invite all attendees to stop by our booth #5721. In the following Newsletter, we are pleased to present the newest DIARECT antigens.

We are looking forward to seeing you in San Diego.

Pleasant reading!

New Recombinant Allergens

Peanut (Arachis hypogaea) allergy accounts for the majority of severe food-related allergic reactions. Symptoms usually develop within minutes after contact with even a trace amount of peanut and may involve cutaneous, cardiovascular, gastrointestinal, genitourinary, and/or respiratory systems and can even lead to anaphylaxis.

A number of peanut allergens have been identified. Of these, Ara h 2 and the related allergen, Ara h 6, have been determined to be considerably more potent than Ara h 1 and Ara h 3, the other peanut allergens that bind IgE from a large percentage of peanut allergic individuals. Ara h 2 and Ara h 6 belong to the family of conglutins. They are related to the 2S albumins and function as seed storage proteins.

In peanut, clinical reactions are associated with individual peanut allergens with specific characteristics. Seed storage proteins are the major allergens in primary peanut allergy, meaning that sensitization occurs to the allergen itself. In contrast, pollen-associated allergies are usually caused by cross-reactions towards inhaled allergens such as Ara h 8 - a Bet v 1 homologue. In regions in which birch tree pollen exposure is prevalent, such as Northern Europe, children and adolescents with an Ara h 8 sensitization and no IgE towards Ara h 1, 2, 3 and 6, typically do not show systemic reactions.

Immediate reactions after eating apple (Malus domestica) are common and often coincide with tree-pollen allergies. Mal d 1 belongs to a class of proteins called pathogenesis-related (PR) proteins which are produced by the plant in the event of a pathogen attack or environmental stress. The allergen shares homologous IgE epitopes with major birch pollen allergen Bet v 1 and Cor a 1 from hazelnut pollen. Apple is a prime example of pollen-fruit syndrome in which people with hay fever develop oral allergic symptoms to food allergens.

Pollens from plants of the Asteraceae family are the most frequent causes of allergies in the northern hemisphere. Due to overlapping flowering seasons and frequent polysensitization with other pollen it can be difficult to correctly diagnose the source of the primary allergen.
Among the six identified allergenic molecules in mugwort (Artemisia vulgaris), Art v 1 is the most prominent, with sensitization ranging from 70 to 95 %. The pollen allergen is a defensin-like protein and an Amb a 4 homolog. In component resolved allergy diagnostics, evaluation of Art v 1 is particularly useful since it is a genuine marker allergen for mugwort and correctly identifies primary sensitization in the vast majority of people.

Stemeseder et al. (2014) Allergo J Int 23:274-80
Razzera et al. (2010) Cell Press DOI 10.1016
Lange et al. (2014) Allergo J Int 23:158-63
Ruth et al. (1998) J Allergy Clin Immunol 102:679-86

For additional product related information or updated product flyers please feel free to contact us at:
Tel: +49 761 47979-0
Email: info@diarect.com

Update on Tick-Borne Disease Antigens

Climate change with a subsequent expansion of vector tick territory, along with changes in land use might affect the epidemiology of all tick-borne infections. DIARECT offers antigens for detection of the causative agents of Babesiosis, Borreliosis, and Anaplasmosis, and is now introducing new products.

Lyme disease, the most common tick-borne disease in the Northern Hemisphere, is caused by Borreliella species. While in Europe the pathogenic genospecies B. afzelii, B. bavariensis, B. garinii, B. spielmanii, and B. burgdorferi sensu stricto are present, only the latter predominates in the United States. A wide range of recombinant Borreliella spp. antigens from these pathogenic genospecies is already available from DIARECT. This portfolio is now expanded by the addition of recombinant DbpA antigens from B. bavariensis, B. garinii and B. spielmanii. Furthermore, due to the expiration of EU patent 0 894 143 B1 regarding the use of VMP-like sequences of pathogenic Borrelia, DIARECT is now offering Borreliella burgdorferi VlsE1 for IVD assay development and/or research use. Please note that several respective US patents are still valid.

Human Granulocytic Anaplasmosis (HGA) is the second most frequently detected tick-borne disease. Causative agent is the rickettsial species Anaplasma phagocytophilum, a Gram-negative obligate intracellular pathogen infecting mammalian hosts worldwide. A. phagocytophilum invades and replicates within neutrophils by employing an array of mechanisms to subvert their bactericidal activity.

Major surface protein 5 (Msp5) is highly conserved within the Anaplasma genus. During biological transmission the 20-kDa protein is expressed in the salivary glands of infected ticks. A. phagocytophilum p44 is a transmembrane protein of the outer membrane and belongs to the Msp2 antigen family. Its putative roles are to allow Anaplasma to adhere to the host cell and also avoid host immune recognition. Both proteins are considered main antigens of antibody response to HGA.

Atifi et al. (2015) Parasitol Res DOI 10.1007/s00436-015-4698-2
Andersen and Davis (2016) Int J Dermatol. 33: 2358-2365
Knowles et al. (1996) J Clin Microbiol 34:2225-2230
Visser et al. (1992) Infect immun 60:5139-5144
Woldehiwet et al. (2010) Vet Parasitol 167:108–122

For questions or additional information please feel free to contact us at:
Tel: +49 761 47979-0
Email: info@diarect.com

Completing the Streptococcus Portfolio: Streptolysin O

Streptococcus pyogenes is a Gram-positive, spherical bacterium often called group A Streptococcus (GAS). This human pathogen is the causative agent of up to 30% of all pharyngitis cases (“Strep Throat”) and Scarlet Fever. Spreading via direct contact and aerosols, it is estimated to cause serious infections in 18 million people worldwide leading to death in 500,000 cases per year.

Serological detection of S. pyogenes infection can be optimized by incorporation of relevant immunogenic parameters. In patient samples antibodies against S. pyogenes arginine deiminase (arcA), transketolase (tkt) and streptolysin O (slo) are detectable.

As a key virulence factor of group A streptococci, streptolysin O is involved in preventing internalization of the bacteria into lysosomes. This cytolytic, extracellular protein shares extensive structural homologies with other sulfhydryl-activated toxins. It is one of the best characterized members of a large, β-barrel pore-forming exotoxin family called cholesterol-dependent cytolysins (CDCs) that are produced by a variety of Gram-positive bacteria, including many strains of β-hemolytic group A, C and G streptococci.

After secretion in a water-soluble monomeric form, streptolysin O binds to the host erythrocyte membranes forming ring-like structures. The presence of cholesterol in the target membrane is required for homo-oligomerization and pore formation through multiple conformational changes which then results in cytolysis.

DIARECT now offers the third S. pyogenes antigen, streptolysin O. This antigen, produced in E. coli, is a double mutant (P427L/W535F) with extremely reduced hemolytic activity, but still retains its immunological activity.

Chiarot et al. (2013) mBio 4(1):e00387-12 
Feil et al. (2014) J Mol Biol 426:785–792
Håkansson et al. (2005) Proc Natl Acad Sci USA 102:5192–7
Hugo et al. (1886) Infect Immun 54:641–5
Sekiya et al. (1993) J Bacteriol 175:5953–61
Tweten et al. (2005) Infect Immun 73:6199–6209

For questions or additional information please feel free to contact us at:
Tel: +49 761 47979-0
Email: info@diarect.com


To facilitate the world-wide sales of our antigens, DIARECT has distribution agreements with select companies.

If you are located in North America, DIARECT’s products are exclusively distributed by:

SurModics IVD, Inc.
9924 West 74th Street
Eden Prairie, MN 55344
Tel +1 952 500 7200
Toll-free +1 800 755 7793
Fax +1 952 500 7201

If you are located in China, DIARECT’s products are distributed by:

Shanghai BioSun Sci&Tech Co., Ltd.
Room K, 5F, Bldg. No.1
825 Zhaojiabang Road
Shanghai 200032
P.R. China
Tel +86 21 54253791
Fax +86 21 64280007



If you would like to receive more detailed information on DIARECT products, please follow this link to our contact and order form.

Contact Details

  • Address: Bötzinger Straße 29 B, 79111 Freiburg, Germany

  • Phone: +49 (0) 761 479 79-0

  • Fax: +49 (0) 761 479 79-29

  • Email: info-dia@bbisolutions.com

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