Bovine serum albumin contained in culture medium used in artificial insemination is an important anaphylaxis risk factor

Microbiological and chemical hazards in cultured meat and methods for their detection

Cultured meat, which involves growing meat in a laboratory rather than breeding animals, offers potential benefits in terms of sustainability, health, and animal welfare compared to conventional meat production. However, the cultured meat production process involves several stages, each with potential hazards requiring careful monitoring and control. Microbial contamination risks exist in the initial cell collection from source animals and the surrounding environment. During cell proliferation, hazards may include chemical residues from media components such as antibiotics and growth factors, as well as microbial issues from improper bioreactor sterilization. In the differentiation stage where cells become muscle tissue, potential hazards include residues from scaffolding materials, microcarriers, and media components. Final maturation and harvesting stages risk environmental contamination from nonsterile conditions, equipment, or worker handling if proper aseptic conditions are not maintained. This review examines the key microbiological and chemical hazards that must be monitored and controlled during the manufacturing process for cultured meats. It describes some conventional and emerging novel techniques that could be applied for the detection of microbial and chemical hazards in cultured meat. The review also outlines the current evolving regulatory landscape around cultured meat and explains how thorough detection and characterization of microbiological and chemical hazards through advanced analytical techniques can provide crucial data to help develop robust, evidence-based food safety regulations specifically tailored for the cultured meat industry. Implementing new digital food safety methods is recommended for further research on the sensitive and effective detection of microbiological and chemical hazards in cultured meat.

Safety evaluation of a buffer used in the lyophilization of canine platelets: type I hypersensitivity reaction in dogs caused by bovine serum albumin

Introduction

The present study was designed to evaluate the safety of substances generally used in the preparation of lyophilized platelet products (LPPs) because the possibility of an immune response to bovine serum albumin (BSA) was considered high when using previously described technology.

Methods

An intradermal skin test, followed by a drug provocation test, was conducted to observe adverse events and identify the substances responsible for an immune response. Five male beagles (2 years old) weighing 12-14 kg were used. The dogs were clinically healthy and had no history of medication use. An intradermal skin test was conducted with each substance [i.e., 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid, sodium chloride, potassium chloride, sodium bicarbonate, theophylline, trehalose, and BSA] used in the conventional freeze-dry method.

Results

In the intradermal skin test, three dogs tested positive at the BSA injection site and showed clinical signs after the intradermal injection, including nausea and vomiting. For the drug provocation test, all dogs received two intravenous injections of an LPP buffer solution. The initial injection was devoid of BSA, whereas the subsequent injection contained BSA. The three dogs that had reacted to BSA in the intradermal skin test exhibited adverse events such as lethargy, vomiting, and nausea immediately after intravenous injection of the LPP buffer containing BSA. All dogs recovered uneventfully after symptomatic treatment in both tests.

Discussion

The high incidence and severity of type I hypersensitivity reactions observed in this study suggested that BSA is unsuitable as a component of canine LPP.

Albumins represent highly cross-reactive animal allergens

Albumins from animals are highly cross-reactive allergens for patients suffering from immunoglobulin E (IgE)-mediated allergy. Approximately 20-30% of cat and dog allergic patients show IgE reactivity and mount IgE-mediated allergic reactions to cat and dog albumin. It is astonishing that allergic patients can develop specific IgE responses against animal albumins because these proteins exhibit a more than 70% sequence identity to human serum albumin (HSA) which is the most abundant protein in the blood of the human body. The sequence identity of cat albumin (Fel d 2) and dog albumin (Can f 3) and HSA are 82% and 80%, respectively. Given the high degree of sequence identity between the latter two allergens and HSA one would expect that immunological tolerance would prohibit IgE sensitization to Fel d 2 and Can f 3. Here we discuss two possibilities for how IgE sensitization to Fel d 2 and Can f 3 may develop. One possibility is the failed development of immune tolerance in albumin-allergic patients whereas the other possibility is highly selective immune tolerance to HSA but not to Fel d 2 and Can f 3. If the first assumption is correct it should be possible to detect HSA-specific T cell responses and HSA-containing immune complexes in sensitized patients. In the latter scenario few differences in the sequences of Fel d 2 and Can f 3 as compared to HSA would be responsible for the development of selective T cell and B cell responses towards Fel d 2 as well as Can f 3. However, the immunological mechanisms of albumin sensitization have not yet been investigated in detail although this will be important for the development of allergen-specific prevention and allergen-specific immunotherapy (AIT) strategies for allergy to albumin.

Anaphylaxis to additives in vaccines

Anaphylaxis in connection with the administration of vaccines occurs only very rarely. Triggers of immunoglobulin IgE-mediated and non-IgE-mediated anaphylaxis—in addition to the active ingredient itself—may be excipients contained in the vaccine due to their special properties. Some of the excipients in medicinal products are the same compounds used as additives in food. Furthermore, residues from the manufacturing process (e.g., chicken egg white, casein, antibiotics, formaldehyde) or contaminants (e.g., from the primary packaging material) may be potential triggers of anaphylaxis in vaccines. This review article provides an overview of ingredients in vaccines that pose an allergenic risk potential. The components of COVID-19 vaccines approved and marketed in Germany are discussed with regard to their potential for triggering anaphylaxis and possible pathophysiological mechanisms involved.

Anaphylaxie auf Zusatzstoffe in Impfstoffen

Anaphylaxien im zeitlichen Zusammenhang mit der Verabreichung von Impfstoffen treten nur sehr selten auf. Auslöser von IgE-vermittelten und nicht IgE-vermittelten Anaphylaxien können neben dem Wirkstoff selbst Hilfsstoffe sein, die aufgrund spezieller Eigenschaften im Impfstoff enthalten sind. Bei den Hilfsstoffen in Arzneimitteln handelt es sich teilweise um dieselben Verbindungen, die als Zusatzstoffe in Lebensmitteln eingesetzt werden. Weiterhin kommen in Impfstoffen Rückstände aus dem Herstellungsprozess (z. B. Hühnereiweiß, Kasein, Antibiotika, Formaldehyd) oder Kontaminationen (z. B. aus dem Primärpackmittel) als potenzielle Auslöser von Anaphylaxien in Frage. Der vorliegende Review gibt einen Überblick über Bestandteile in Impfstoffen, von denen ein allergenes Risikopotenzial ausgeht. Die Bestandteile der in Deutschland zugelassenen COVID-19-Impfstoffe als potenzielle Auslöser von Anaphylaxien und mögliche pathophysiologische Mechanismen werden diskutiert.

Zitierweise: Mahler V, Junker AC. Anaphylaxis to additives in vaccines. Allergo J Int 2022;31: 123-36

https://doi.org/10.1007/s40629-022-00215-8

State-of-the-Art on Biomarkers for Anaphylaxis in Obstetrics

Anaphylaxis is an unpredictable systemic hypersensitivity reaction and constitutes a high risk of maternal and fetal morbidity and mortality when occurring during pregnancy. Currently, the acute management of anaphylaxis is based on clinical parameters. A total serum tryptase is only used to support an accurate diagnosis. There is a need to detect other biomarkers to further assess high-risk patients in obstetrics. Our objective is to present biomarkers in this complex interdisciplinary approach beyond obstetrician and anaesthetic management. Candidate biomarkers derive either from mediators involved in immunopathogenesis or upcoming molecules from systems biology and proteomics. Serum tryptase is determined by singleplex immunoassay method and is important in the evaluation of anaphylactic mast cell degranulation but also in the assessment of other risk factors for anaphylaxis such as systemic mastocytosis. Another category of biomarkers investigates the IgE-mediated sensitization to triggers potentially involved in the etiology of anaphylaxis in pregnant women, using singleplex or multiplex immunoassays. These in vitro tests with natural extracts from foods, venoms, latex or drugs, as well as with molecular allergen components, are useful because in vivo allergy tests cannot be performed on pregnant women in such a major medical emergency due to their additional potential risk of anaphylaxis.

Molecular diagnosis in cat allergy

Domestic cats represent one of the most common sources of indoor allergens. All over the world, many households own cats, whose allergens are persistent and widespread. Cat allergy itself is frequent, and its symptoms vary from rhinoconjunctivitis to life-threatening asthma. In vitro diagnosis using precision medicine allergy immunoassays is important because natural cat dander extracts may differ in quality and quantity of some of the individual allergen components and other molecules. In the component-resolved diagnosis of cat allergy, singleplex and multiplex specific immunoglobulin (Ig) E assays include use of the cat-specific major allergen, secretoglobin Fel d 1 (as a species-specific molecule), other allergen components (such as lipocalins Fel d 4, cross-reacting with other animal similar molecules, and Fel d 7, present in small quantities in natural extracts), and serum albumin Fel d 2 (related to the cat-pork syndrome). IgA Fel d 5 and IgM Fel d 6 are not available as allergen components in the current commercial IgE immunoassays, but they may impair the in vitro diagnostic evaluation of cat allergy because galactose-α1,3-galactose is an IgE-binding epitope of these native feline allergens. The benefits of molecular-based cat allergy diagnosis are continually evaluated, as the role of recombinant allergen components already known is detailed and new other molecules of interest may be discovered in the future.

Xenogeneic-free generation of vascular smooth muscle cells from human induced pluripotent stem cells for vascular tissue engineering

Development of mechanically advanced tissue-engineered vascular grafts (TEVGs) from human induced pluripotent stem cell (hiPSC)-derived vascular smooth muscle cells (hiPSC-VSMCs) offers an innovative approach to replace or bypass diseased blood vessels. To move current hiPSC-TEVGs toward clinical application, it is essential to obtain hiPSC-VSMC-derived tissues under xenogeneic-free conditions, meaning without the use of any animal-derived reagents. Many approaches in VSMC differentiation of hiPSCs have been reported, although a xenogeneic-free method for generating hiPSC-VSMCs suitable for vascular tissue engineering has yet to be established. Based on our previously established standard method of xenogeneic VSMC differentiation, we have replaced all animal-derived reagents with functional counterparts of human origin and successfully derived functional xenogeneic-free hiPSC-VSMCs (XF-hiPSC-VSMCs). Next, our group developed tissue rings via cellular self-assembly from XF-hiPSC-VSMCs, which exhibited comparable mechanical strength to those developed from xenogeneic hiPSC-VSMCs. Moreover, by seeding XF-hiPSC-VSMCs onto biodegradable polyglycolic acid (PGA) scaffolds, we generated engineered vascular tissues presenting effective collagen deposition which were suitable for implantation into an immunodeficient mice model. In conclusion, our xenogeneic-free conditions for generating hiPSC-VSMCs produce cells with the comparable capacity for vascular tissue engineering as standard xenogeneic protocols, thereby moving the hiPSC-TEVG technology one step closer to safe and efficacious clinical translation.

Fertility and allergy: Is there a correlation?

Approximately 10% of couples have difficulties conceiving. Idiopathic infertility affects 10–15% of infertile couples. Some suspected causes of idiopathic infertility are lifestyle factors such as stress, diet, smoking, obesity, lack of physical exercise and alcohol consumption. At the same time, allergies and bronchial asthma are growing health problems in developed countries. Therefore, this study addresses the possible correlation between atopic diseases and fertility. Several interesting cases of patients presenting symptoms of HSPH (human seminal plasma hypersensitivity) have been reported to date. In the majority of cases, allergy to semen is the IgE-dependent response to proteins contained in the seminal plasma. Observations indicating that patients presenting symptoms of HSPH are primarily allergic to allergens of dogs are particularly interesting. The structure of dog allergen Can f 5 is similar to the human PSA (55–60% similarity in the sequence of amino acids). This may explain the presence of IgE-dependent reactions following contact with semen during sexual intercourse in women allergic to dog fur. This article presents the current state of knowledge on the phenomenon.

Characterization of recombinant human and bovine thyroid-stimulating hormone preparations by mass spectrometry and determination of their endotoxin content

Background

The TSH stimulation test to confirm canine hypothyroidism is commonly performed using a recombinant human TSH (rhTSH), as up to date, canine TSH is not yet commercially available. Limiting factors for the use of rhTSH are its high costs and occasional difficulties in product availability. Less expensive bovine TSH preparations (bTSH) purified from bovine pituitary glands are readily commercially available. The aim of this study was to evaluate two different bTSH products as alternative to rhTSH using mass spectrometry.

Results

More than 50 proteins, including other pituitary hormones, bovine albumin, hemoglobin, and tissue proteins were identified in the bTSH preparations. In contrast, rhTSH proved to be a highly pure product. Significantly higher endotoxin levels could be detected in all bTSH products compared to the rhTSH.

Conclusions

Both bTSH products are crude mixtures and therefore not an acceptable alternative to rhTSH. Their use should be discouraged to prevent unintended side effects.

Serum albumins-unusual allergens

BACKGROUND

Albumins are multifunctional proteins present in the blood serum of animals. They can bind and transport a wide variety of ligands which they accommodate due to their conformational flexibility. Serum albumins are highly conserved both in amino acid sequence and three-dimensional structure. Several mammalian and avian serum albumins (SAs) are also allergens. Sensitization to one of the SAs coupled with the high degree of conservation between SAs may result in cross-reactive antibodies in allergic individuals. Sensitivity to SA generally begins with exposure to an aeroallergen, which can then lead to cross-sensitization to serum albumins present in food.

SCOPE OF REVIEW

This review focuses on the allergenicity of SAs presented in a structural context.

MAJOR CONCLUSIONS

SA allergenicity is unusual taking into account the high sequence identity and similarity between SA from different species and human serum albumin. Cross-reactivity of human antibodies towards different SAs is one of the most important characteristics of these allergens.

GENERAL SIGNIFICANCE

Establishing a relationship between sequence and structure of different SAs and their interactions with antibodies is crucial for understanding the mechanisms of cross-sensitization of atopic individuals. Structural information can also lead to better design and production of recombinant SAs to replace natural proteins in allergy testing and desensitization. Therefore, structural analyses are important for diagnostic and treatment purposes. This article is part of a Special Issue entitled Serum Albumin.

Testing for hypersensitivity to seminal fluid-free spermatozoa

Hypersensitivity to human semen (HHS) is an increasingly reported condition with symptoms manifested locally and systemically, which in some cases may result in anaphylaxis. This report describes four cases of HHS all with positive allergy skin prick tests to partner's whole semen. None of the patients elicited a response to seminal fluid-free washed spermatozoa. In cases of high risk of anaphylaxis, we recommend avoiding exposure to semen. By carrying out an allergy skin prick test on seminal fluid-free washed spermatozoa, the risk of immunogenic reaction to the spermatozoa could be eliminated.

Role of sensitization to mammalian serum albumin in allergic disease

Serum albumin (SA) constitutes an intriguing puzzle that is involved in allergic sensitizations from different sources and induces different clinical manifestations. In this article, we describe the role of sensitization to SAs in inducing allergic diseases and the complex interactions and cross-reactivity between SA resulting from its presence in various mammalian tissues and fluids. SAs alone are an uncommon cause of allergic sensitization in airways, but these allergenic proteins likely play a significant role as cross-reacting allergens in individuals sensitized to several types of animal dander. SAs are a minor allergen in milk but a major allergen in meats. Recently, bovine SA has been added to the culture medium of spermatozoids used for artificial insemination. As a consequence, some case reports have shown that bovine SA may be a causative agent in severe anaphylaxis after standard intrauterine insemination or in vitro fertilization.