EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Adequate levels of dietary sulphur amino acids impart improved liver and gut health in juvenile yellowtail kingfish (Seriola lalandi)

The sulphur amino acids methionine (Met) and cysteine (Cys) and their derivative taurine (Tau) are metabolically active molecules with interlinked roles in nutritional requirements. Deficiencies in these nutrients are linked to poor growth and health; however, the impacts of these deficiencies on organ structure and function are largely unknown. This study examined the effects of dietary Met, Cys and Tau fed at different levels on yellowtail kingfish (YTK) liver histology and surface colour, plasma biochemistry and posterior intestine histology. Samples were collected from two dose-response feeding trials that quantified (1) the Tau requirement and sparing effect of Met by feeding YTK diets containing one of seven levels of Tau at one of two levels of Met and (2) the Met requirement and sparing effect of Cys by feeding YTK diets containing one of five levels of Met at one of two levels of Cys. YTK fed inadequate levels of dietary Met, Cys and Tau exhibited thicker bile ducts, less red livers, more intestinal acidic goblet cell mucus and supranuclear vacuoles and less posterior intestinal absorptive surface area. Further, thicker bile ducts correlated with less red livers (a*, R), whereas increased hepatic fat correlated with a liver yellowing (b*). Our results indicate a shift towards histological properties and functions indicative of improved intrahepatic biliary condition, posterior intestinal nutrient absorption and homoeostasis of YTK fed adequate amounts of Met, Cys and Tau. These findings may assist in formulating aquafeed for optimised gastrointestinal and liver functions and maintaining good health in YTK.

A targeted metabolomics approach for clinical diagnosis of inborn errors of metabolism

Metabolome, the ultimate functional product of the genome, can be studied through identification and quantification of small molecules. The global metabolome influences the individual phenotype through clinical and environmental interventions. Metabolomics has become an integral part of clinical research and allowed for another dimension of better understanding of disease pathophysiology and mechanism. More than 95% of the clinical biochemistry laboratory routine workload is based on small molecular identification, which can potentially be analyzed through metabolomics. However, multiple challenges in clinical metabolomics impact the entire workflow and data quality, thus the biological interpretation needs to be standardized for a reproducible outcome. Herein, we introduce the establishment of a comprehensive targeted metabolomics method for a panel of 220 clinically relevant metabolites using Liquid chromatography-tandem mass spectrometry (LC-MS/MS) standardized for clinical research. The sensitivity, reproducibility and molecular stability of each targeted metabolite (amino acids, organic acids, acylcarnitines, sugars, bile acids, neurotransmitters, polyamines, and hormones) were assessed under multiple experimental conditions. The metabolic tissue distribution was determined in various rat organs. Furthermore, the method was validated in dry blood spot (DBS) samples collected from patients known to have various inborn errors of metabolism (IEMs). Using this approach, our panel appears to be sensitive and robust as it demonstrated differential and unique metabolic profiles in various rat tissues. Also, as a prospective screening method, this panel of diverse metabolites has the ability to identify patients with a wide range of IEMs who otherwise may need multiple, time-consuming and expensive biochemical assays causing a delay in clinical management.

Adiponectin confers protection from acute colitis and restricts a B cell immune response

Adiponectin demonstrates beneficial effects in various metabolic diseases, including diabetes, and in bowel cancer. Recent data also suggest a protective role in colitis. However, the precise molecular mechanisms by which adiponectin and its receptors modulate colitis and the nature of the adaptive immune response in murine models are yet to be elucidated. Adiponectin knock-out mice were orally administered dextran sulfate sodium for 7 days and were compared with wild-type mice. The severity of disease was analyzed histopathologically and through cytokine profiling. HCT116 colonic epithelial cells were employed to analyze the in vitro effects of adiponectin and AdipoR1 interactions in colonic injury following dextran sulfate sodium treatment. Adiponectin knock-out mice receiving dextran sulfate sodium exhibited severe colitis, had greater inflammatory cell infiltration, and an increased presence of activated B cells compared with controls. This was accompanied by an exaggerated proinflammatory cytokine profile and increased STAT3 signaling. Adiponectin knock-out mouse colons had markedly reduced proliferation and increased epithelial apoptosis and cellular stress. In vitro, adiponectin reduced apoptotic, anti-proliferative, and stress signals and restored STAT3 signaling. Following the abrogation of AdipoR1 in vitro, these protective effects of adiponectin were abolished. In summary, adiponectin maintains intestinal homeostasis and protects against murine colitis through interactions with its receptor AdipoR1 and by modulating adaptive immunity.

IL-4Rα-responsive smooth muscle cells contribute to initiation of TH2 immunity and pulmonary pathology in Nippostrongylus brasiliensis infections

Nippostrongylus brasiliensis infections generate pulmonary pathologies that can be associated with strong T(H)2 polarization of the host's immune response. We present data demonstrating N. brasiliensis-driven airway mucus production to be dependent on smooth muscle cell interleukin 4 receptor-α (IL-4Rα) responsiveness. At days 7 and 10 post infection (PI), significant airway mucus production was found in IL-4Rα(-/lox) control mice, whereas global knockout (IL-4Rα(-/-)) and smooth muscle-specific IL-4Rα-deficient mice (SM-MHC(Cre) IL-4Rα(-/lox)) showed reduced airway mucus responses. Furthermore, interleukin (IL)-13 and IL-5 cytokine production in SM-MHC(Cre) IL-4Rα(-/lox) mice was impaired along with a transient reduction in T-cell numbers in the lung. In vitro treatment of smooth muscle cells with secreted N. brasiliensis excretory-secretory antigen (NES) induced IL-6 production. Decreased protein kinase C (PKC)-dependent smooth muscle cell proliferation associated with cell cycle arrest was found in cells stimulated with NES. Together, these data demonstrate that both IL-4Rα and NES-driven responses by smooth muscle cells make important contributions in initiating T(H)2 responses against N. brasiliensis infections.

Exposure to flour dust in South African supermarket bakeries: modeling of baseline measurements of an intervention study

INTRODUCTION

Exposure to flour dust has been reported as an important risk factor for allergic respiratory disease among bakery workers. A high prevalence of allergic sensitization and asthma was recently reported in South African supermarket bakeries. The aim of this study was to conduct a detailed exposure assessment of these bakeries so as to provide the baseline for a broader intervention study.

METHODS

A total of 211 full-shift personal samples were collected on randomly selected individuals within five different job categories in 18 bakeries. The samples were analyzed for particulate mass and specific flour dust allergens (wheat, rye, and fungal alpha-amylase). Exposure models were developed using job, bakery size, tasks, and specific ingredients used. Bakery and worker were regarded as random effect components.

RESULTS

Bread bakers had the highest average (geometric mean) exposures (1.33 mg m(-3) flour dust particulate, 13.66 microg m(-3) wheat allergens, and 5.14 microg m(-3) rye allergens). For alpha-amylase allergens, most samples were below the limit of detection for several occupational titles. In the mixed effect models, the significant predictors of elevated exposure to inhalable dust particulate as well as wheat and rye allergen concentrations were large bakery size, bread baking, and use of cereal flours, while tasks such as confectionery work were negatively correlated with these exposure metrics. Weighing tasks and use of premix products were associated with increased exposure to fungal alpha-amylase. A high correlation between particulate dust and wheat (r = 0.84) as well as rye (r = 0.86) was observed, with a much lower correlation between particulate dust and fungal alpha-amylase (r = 0.33). Overall, a low proportion (39%) of bakery stores implemented various control measures to reduce dust exposures in the bakeries.

CONCLUSIONS

This study confirms that current exposure control strategies in supermarket bakery stores are inadequate in reducing dust exposures to protect the health of bakery workers.

Physiological and morphological colour change in Antarctic krill, Euphausia superba: a field study in the Lazarev Sea

Antarctic krill, Euphausia superba, is very susceptible to harmful solar radiation because of its unique genetic setup. Exposure occurs in spring to autumn during vertical diel migration and during occasional daytime surface-swarming. We have investigated colour change in Antarctic krill, Euphausia superba, during summer and winter in the Lazarev Sea in response to ultraviolet radiation (UVR) and photosynthetically active radiation (PAR). Short-term physiological colour change and long-term(seasonal) morphological colour change are present. Both are facilitated by a single type of monochromatic red chromatophore, i.e. erythrophores, of 20–450 μm diameter. Superficial erythrophores cover large dorsal areas, especially above vital organs (brain, sinus glands), additional`profound' erythrophores cover internal organs (heart, gut, nerve cords). Short-term change in light regime causes rapid physiological colour change along dense bundles of microtubules: pigment disperses into chromorhizae upon exposure to PAR and UVA and to a lesser extent to UVB. Darkness leads to aggregation of pigment in the centre and hence blanching. There is no circadian rhythm in the dispersal state of erythrophores present in winter. Physiological colour change in adult krill is two to three times more rapid in summer than in winter. Furthermore, seasonal changes in light regime also result in a profound morphological colour change: in summer animals, abdominal astaxanthin concentration is 450% and erythrophore count is 250–480%higher than in winter krill. We conclude from our results, that pigmentation of E. superba serves in the protection from harmful solar radiation and is adapted to the varying diel and seasonal light conditions.

Interpretation of scoring functions using 3D molecular fields. Mapping the diacyl-hydrazine-binding pocket of an insect ecdysone receptor

A method is presented for the interpretation of receptor docking score values (rough measures of binding affinities) of ligands in terms of 3D molecular field interaction contributions. The FlexX and FlexX-Pharm methods were used to dock the structures of designed sets of ligands into the ligand-binding pocket of a selected receptor. In the next step the relationship was investigated between the FlexX and CScore scores and 3D molecular fields obtained for the docked conformations of the ligands, using the CoMFA (Comparative Molecular Field Analysis) and CoMSIA (Comparative Molecular Similarity Indices Analysis) methods. The approach yielded highly significant CoMFA and CoMSIA models demonstrating that a high portion of the variance in the docking score values of the ligands can be explained by steric, electrostatic, hydrophobic, and hydrogen bond donor and acceptor molecular field interaction contributions. The approach was exemplified by using the crystal structure of the ligand-binding domain of the ecdysone receptor (EcR) of the moth Heliotis virescens as well as virtual molecule libraries of analogues of known diacyl-hydrazine (DAH) type ecdysteroid agonists. By docking appropriately designed virtual compound libraries into the DAH binding pocket of EcR followed by CoMFA and CoMSIA of the docked conformations, hitherto unexplored regions of the receptor cavity could be mapped. By mapping the significant molecular field interaction contributions onto the model of the receptor-ligand complex, important receptor-ligand interactions could be highlighted that may help the design of novel highly scored receptor ligands. An advantage of the method is that no experimental biological activity data are required to exhaustively map the receptor-binding site.

Analysis of intra-uterine cytokine concentration and matrix-metalloproteinase activity in women with recurrent failed embryo transfer

BACKGROUND

In all IVF programmes, some patients fail to achieve an ongoing pregnancy, even after numerous embryo transfer procedures. An unfavourable environment within the uterus might be a contributory factor to such recurrent implantation failure. This question was addressed by measuring cytokine concentrations and matrix metalloproteinase activities in fluid derived from uterine irrigation of such patients.

METHODS AND RESULTS

The uterine cavities of 22 patients who had previously undergone embryo transfer of at least 10 embryos without ongoing pregnancy were irrigated during the luteal phase. The resultant fluid was assayed for the concentration of interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, leukaemia inhibitory factor (LIF), IL-10 and matrix metalloproteinase (MMP) -2 and -9 activity. The results were compared with those of a control population of women known to be previously fertile (n = 16) and also with women with recurrent spontaneous abortion (n = 13). In the recurrent implantation failure group, the MMP score and IL-1beta concentration were significantly higher than those in the control group, whereas concentrations of IFN-gamma and IL-10 were significantly lower.

CONCLUSIONS

In IVF patients with recurrent implantation failure, an altered pattern of intra-uterine cytokine concentration and MMP activity was observed.

Expression and localization of thioredoxin during early implantation in the marmoset monkey

Thioredoxin is a powerful redox protein expressed in invasive cytotrophoblasts and essential for blastocyst implantation in mice. Isolated marmoset thioredoxin cDNA showed that the deduced amino acid sequence differed from the human sequence by four amino acids. The close homology of thioredoxin in the two species enabled us to use monoclonal antibodies against human thioredoxin to detect marmoset thioredoxin in implantation sites, blastocysts and culture medium. Immunocytochemistry on marmoset implantation sites, on pregnancy days 12 and 15, showed that thioredoxin is highly expressed in uterine luminal epithelium, glands and in some endometrial stromal cells. In attached blastocysts, thioredoxin staining was detected in mural and polar trophoblast cells and both visceral and parietal endoderm, whereas no staining was present in the inner cell mass. A similar pattern of thioredoxin expression was detected in hatched blastocysts attached to Matrigel in tissue culture. Trophoblastic vesicles derived from blastocysts expressed thioredoxin in inner endoderm-like cells and outer trophoblast-like cells and secreted thioredoxin into the culture medium. These experiments have demonstrated thioredoxin expression during early stages of embryo-maternal interaction. We propose that thioredoxin protects the early placenta from oxidative damage and that the marmoset is a valuable model for studying thioredoxin regulation and function during implantation and blastocyst differentiation.

Characteristics of the uterine luminal surface epithelium at preovulatory and preimplantation stages in the marmoset monkey

Light and electron microscopy was used to examine the apical luminal epithelial surface of the uterus at preovulatory and preimplantation stages in the marmoset monkey. Luminal surface charge, detected by cationic ferritin staining, progressively decreased from preovulation to day 11 of pregnancy. The smooth, regular apical plasma membrane at preovulatory stages was in contrast to the convoluted, irregular surface observed during early pregnancy, especially at 1 day before blastocyst implantation. Profiles of microvilli were also altered, becoming thicker and more irregular during early pregnancy. Within the epithelial cell body, cyclic morphologic changes were seen, largely in association with secretory organelles. Giant phagocytic bodies were prominent at all stages examined, although their composition and intensity of staining varied throughout the cycle. Weak to moderate estrogen alpha and progesterone receptor immunostaining of the luminal epithelium was found during preovulatory and early pregnancy stages. This study describes complex cyclic changes in the morphology and biochemical make-up of the uterine luminal epithelial surface in a New World monkey in preparation for blastocyst attachment.

Corticotropin-releasing hormone-binding protein in primates

In humans, placental corticotropin-releasing hormone (CRH) production has been linked to the determination of gestational length, and a late gestational fall in CRH-binding protein (CRH-BP) has been linked to the onset of parturition. Expression of placental CRH mRNA is limited to primates, and only in man has a circulating CRH-BP been described. As the fall in CRH-BP in late gestation has been associated with parturition in humans, we sought to determine whether a CRH-BP circulated in the plasma of other primates. It is unclear whether maternal plasma CRH concentrations are elevated in New World monkeys and prosimians. We have therefore performed CRH plasma measurements in the blood of pregnant marmosets, in several species of lemur, and in pregnant and fetal rhesus monkeys as a positive control. Using gel chromatography, CRH-BP was detected in the human, gorilla, chimpanzee, orangutan, gibbon, macaque, squirrel monkey, and marmoset, but was absent in the mandrill, spider monkey, and lemur. CRH was detected in the plasma of pregnant marmosets and rhesus monkeys. CRH was also detected in the fetal rhesus monkey, but at lower concentrations than in maternal plasma. CRH immunoreactivity was not detectable in the plasma of pregnant lemurs or in extracts of lemur placenta. In conclusion, a circulating binding protein for CRH exists in all species of apes but occurs variably among New World and Old World monkeys and is absent in lemurs. The variable occurrence of the CRH-BP does not support a role for this protein in the mechanism of parturition in primates. Maternal CRH is elevated in the pregnant marmoset and rhesus, and may play a role in the pregnancy of New and Old World monkeys.

In vitro models of human blastocyst implantation

This paper reviews different in vitro models used for the study of blastocyst implantation in animals and the human. Furthermore, results from human blastocyst-endometrial interactions in vitro, investigated by scanning electron microscopy (SEM), light microscopy (LM) and transmission electron microscopy (TEM), are presented. SEM demonstrates the preference of human blastocysts to adhere to pinopode-presenting areas on endometrial cell cultures. LM and TEM show that the first morphological sign of cell contact, defined as junction formation, is present at the apical-to-lateral border of endometrial epithelial cells, whereas trophoblast attachment to apical endometrial epithelial plasma membranes was not observed. More advanced stages illustrate that the human blastocyst penetrates the epithelial lining by the intrusive penetration mechanism.

Comparative three-dimensional quantitative structure-activity relationship study of safeners and herbicides

The competitive antagonist hypothesis for safeners and herbicides was investigated by studying the 3D similarity between 28 safener and 20 herbicide molecules in their putative biologically active, low-energy conformations using comparative molecular field analysis (CoMFA). In addition, CoMFA provided information about the structural requirements for the interactions of safeners and herbicides with a proteinaceous component (SafBP) isolated from etiolated corn seedlings. Statistically significant CoMFA models have been developed for the united and separate safener and herbicide molecule sets using retrospective binding affinity data of the ligands measured at the SafBP receptor. The predictive power of the models was characterized by squared cross-validated correlation coefficients (q(2)) of 0.708, 0.564, and 0.4000 for the united safener plus herbicide set, the safener set, and the herbicide set, respectively. The CoMFA results support the competitive antagonist hypothesis between certain types of safeners and herbicides. The findings suggest that structural similarity between these two classes of agrochemicals is a useful guide in the design of new safeners.

Implantation in the marmoset monkey: expansion of the early implantation site

This study was initiated to examine the early stages of trophoblast adhesion and invasion during implantation in the marmoset. Seven implantation sites were found in the uteri of four marmosets taken between days 13 and 15 of gestation. Three implantation sites in two uteri were examined in detail by electron microscopy. Between days 13 and 15, the marmoset implantation site expanded peripherally by adding areas where syncytial trophoblast penetrated between uterine luminal epithelial cells. Such penetrating masses often bridged openings of endometrial glands, shared junctional complexes with the uterine epithelial cells between which they are infiltrating, and subsequently reached the residual basal lamina of the uterine luminal epithelium. Centripetal to the peripheral region was an intermediate region in which syncytial trophoblast overlay individual clusters of epithelial cells and rested along the basal lamina. In this region there was some evidence of fusion of syncytial trophoblast with uterine epithelial cells. In the central region of the implantation site near the inner cell mass and amnion the trophoblast formed elaborate lamellipodia in relation to the basal lamina. In one of the three specimens examined with electron microscopy there were two foci where trophoblast penetrated through the basal lamina. It was also in the central region that trophoblast penetrated farthest into the uterine glands. The gland cells closest to trophoblast were less closely associated and lost their columnar shape, forming large round cells similar to the epithelial plaque cells of other primates. Where two blastocysts implanted on the same side of the uterus a conjoint membrane was formed which in regions consisted solely of syncytial trophoblast with two basal surfaces and two basal laminas. The prolonged period of time when the implantation site expands within the plane of the uterine epithelium (trophoblastic plate stage) and the peripheral to central sequence in extent of development make this primate a particularly useful animal for studies of trophoblast adhesion to and penetration of the uterine luminal epithelium.

[Molecular modeling studies of prolyl endopeptidase inhibitors]

Prolyl endopeptidase, a serine protease is considered to play an important role in the degradation of neuropeptides capable of changing the performance in learning and memory tasks in both animal and human. The inhibitors seem to be promising drug candidates to treat and prevent diseases with associated memory loss such as senile dementia. In the last decade advanced and improved new technologies have appeared to stimulate ideas in the design and synthesis of new drug molecules. The goal of this short communication is to review our results and observations, exemplified by our research on the inhibitors of prolyl endopeptidase. Among them qualitative and quantitative structure-activity relationship studies using conformational analyses, NMR measurements, pharmacophoric plots and CoMFA models are summarised.

Marmoset monkey trophoblastic tissue growth and matrix metalloproteinase secretion in culture

Marmoset monkey blastocysts maintained in culture produced trophoblastic vesicles up to 4 mm in diameter that were subdivided into fragments and subcultured to produce new vesicles. These tissues are composed of an outer layer of trophoblast-like cells and an inner layer of endoderm-like cells, and resemble a blastocyst wall. When such vesicles were cultured in serum-free medium for 14 days, they increased in size but there was no significant difference in their protein content at the end of culture. The proliferation index, measured by BrdU incorporation, varied considerably within and between vesicles. The purpose of this investigation was to determine which matrix metalloproteinases are secreted by marmoset monkey trophoblastic tissue in vitro, and the effect of extracellular laminin on this secretion. It was determined by zymography that the vesicles secreted matrix metalloproteinase 2, but not matrix metalloproteinase 9, and that matrix metalloproteinase 2 was secreted as the proenzyme (72 kDa). Matrix metalloproteinases 1, 3 and 7 were not detectable in the culture medium. The addition of laminin (5-20 micrograms ml-1), either as a substrate or in solution in the medium, did not have a consistent effect on matrix metalloproteinase 2 secretion during the culture period. The vesicles were found to express both matrix metalloproteinases 2 and 9 in both types of cell when examined by immunohistochemistry. The expression of matrix metalloproteinase 9 in the vesicles, but the absence of its secretion, indicates that specific factors, possibly of endometrial origin, may be required for inducing secretion.

Ultrastructural studies of glycan changes in the apical surface of the uterine epithelium during pre-ovulatory and and pre-implantation stages in the marmoset monkey

It has been postulated that carbohydrates are involved in a variety of cell-cell interactions including blastocyst implantation. In primates, there are only limited investigations on the ultrastructural localisation of the cyclic changes in uterine epithelial surface carbohydrates. Our aim was to investigate such changes during the pre-ovulatory and pre-implantation stages of the reproductive cycle in the marmoset monkey. After fixation of endometrial tissues, avidin-ferritin lectin cytochemistry was employed for apical surface glycan detection at the ultrastructural level. Five lectins were used including Canavalia ensiformis (Con A), Lotus tetragonolobus (LTA), Glycine max (SBA), Phytolacca americana (PWM) and Triticum vulgaris (WGA). Morphometry was used to quantitate changes in the intensity of lectin staining by determining the total number of ferritin particles per unit length of membrane. Surface and intra-cytoplasmic vesicles, stained by the lectins, were also examined. Quantitative ferritin assessment showed that 1 day before presumed implantation (days 11 to 12 after ovulation in the marmoset monkey) there was a significant increase in Con A, LTA and SBA staining on the apical uterine epithelial plasma membrane compared to the pre-ovulatory phase and earlier stages of pregnancy (days 4-8 after ovulation). A significant increase in PWM was also detected from early pregnancy to pre-implantation stages. All lectins except WGA produced reproducible staining within reproductive cycle groups. The greatest variation and intensity of epithelial surface staining was observed with WGA and the weakest with LTA. The patchy staining with LTA compared with thick coverage by WGA indicated the complexity of the carbohydrate arrangement in the glycocalyx of the uterine surface plasma membrane. Reduction of WGA reactivity after neuraminidase treatment suggested that the lectin binding might be related to the presence of heavily sialylated apical uterine membrane glycoconjugates. This is the first high-resolution study in primates to report quantitative cyclic changes in fucosyl, galactosyl, glucosyl, and mannosyl sugar residues of the apical uterine epithelial glycocalyx. The findings support the concept that uterine epithelial glycocalyx surface carbohydrates play a role in preparing a receptive uterine surface.

Reactivity of human trophoblast monoclonal antibodies with marmoset monkey trophoblast cultures

The aim of this study was to determine whether cultured trophoblast tissues, derived from the trophectoderm of marmoset monkey blastocysts, contain homologues of human trophoblast antigens. This is an essential prerequisite to determine whether the marmoset may be a suitable model for preclinical testing of a human antitrophoblast antigen for fertility regulation. Previously evaluated monoclonal antibodies from the Flinders University laboratory, which reacted with human trophoblast with a high degree of specificity, were tested for immunohistochemical reactivity using an immunoperoxidase detection method on both frozen and paraformaldehyde-fixed sections of the cultured marmoset monkey trophoblast. All monoclonal antibodies raised against human placenta reacted positively, when compared to controls, suggesting that human and marmoset trophoblast cells share common epitopes. The specificity of the monoclonal antibodies was investigated by determining whether there was cross-reactivity with other marmoset monkey tissues, including adrenal, spleen, kidney, liver, muscle, ovary and testis. The specificities of the monoclonal antibodies on these marmoset tissues were similar to those previously found on the corresponding human tissues. We have concluded that marmoset monkey trophoblast exhibits homologues of human trophoblast antigens. The findings also suggest that marmoset monkeys should be evaluated further as a primate model to test suitable target antigens for antitrophoblast vaccines that may be useful contragestation agents in humans.

Analysis of chorionic gonadotrophin secreted by cultured human blastocysts

Embryos produced in an in-vitro fertilization (IVF) programme, but which were unsuitable for transfer to patients because they originated from one (1PN) or three pronuclear (3PN) oocytes or because they originated from two pronuclear (2PN) oocytes but cleaved normally, were maintained in tissue culture. The embryos that progressed to blastocytes were cultured to day 14 of development in order to study their daily output of human chorionic gonadotrophin (HCG). Blastocysts that released large amounts of immunoreactive HCG, which continued to increase daily during the study period, provided the culture supernatants used in the present studies. The heterogeneity of HCG released by blastocyst tissues on days 11 and 14 of development was studied by a chromatofocusing method which separates the isoforms of the gonadotrophin based on differences in their isoelectric points. It was found that the secreted HCG was composed of several molecular forms and that this heterogeneity changed from day 11 to 14 of development. The early blastocyst tissues produced more acidic HCG isoforms than the more advanced embryonic tissues. Differences in the apparent ploidy of the blastocyst tissues studied did not affect significantly the distribution of the HCG isoforms secreted either on day 11 or day 14 of development. These results suggest that the bioactivity of the HCG secreted by blastocytes may change with time and with differentiation of the trophectoderm. In addition, the results suggest that the ploidy of early blastocytes does not influence the nature of the HCG secreted.

The spectrum of allergy to South African bony fish (Teleosti). Evaluation by double-blind, placebo-controlled challenge

OBJECTIVE

The aim of this study was to assess the spectrum of allergy to South African bony fish (Class Teleosti), crustaceans and molluscs and to confirm or refute suspected allergy, specifically to bony fish, by double-blind, placebo-controlled food challenge (DBPCFC).

DESIGN

Patients were recruited by means of a seafood allergy questionnaire. Subjects with reported allergy to hake, yellowtail, salmon and mackerel were investigated by means of skin-prick tests, RASTs and Western blot analysis. For those subjects with test results that were either all negative or equivocal, a definitive diagnosis of clinical sensitivity was made on the basis of DBPCFC.

SETTING

Volunteer population-based cohort in the Western Cape.

PARTICIPANTS

105 volunteer subjects with suspected fish allergy were recruited by advertising in the local press.

MAIN OUTCOME

Species-specific bony fish allergy was confirmed or refuted by DBPCFC.

RESULTS

The four most common seafood species reported to cause adverse reactions were prawns (46.7%), crayfish (43.8%), abalone (35.2%) and black mussels (33.3%). The four most common bony fish species to cause reactions were hake (24.8%), yellowtail (21.9%), salmon (15.2%) and mackerel (15.2%). Seven DBPCFCs were performed and two open challenges. Skin-prick tests produced one false-negative result. Western blots produced one false-negative and one false-positive result. The RAST had a 100% correlation with DBPCFC.

CONCLUSIONS

Local bony fish represent a significant cause of clinical reactions to seafood in the Western Cape. Although skin-prick tests, RASTs and Western blotting tests assist in the documentation of an IgE responder state, confirmation of clinical sensitivity can only be made with certainty by means of DBPCFC.

Blastocyst-endometrial interaction: an appraisal of some old and new ideas

The nature of the early interaction between blastocyst and endometrial epithelium is known to be highly specific within individual species. Despite this unique initial interaction, the trophoblast promptly establishes a common theme as invasive cells penetrate the endometrium and colonize its local blood vessels. In all animals with this type of implantation the blastocyst plays a more active role than the endometrial epithelium. The aggressive behaviour of the blastocyst may be induced by signals from the endometrium which has been primed with preimplantation ovarian steroids. Activation of the blastocyst may reflect triggering of synchronized paracrine loops, activated during the implantation window. Endometrial cytokines and eicosanoids are probably the primary signals that drive the interlinking paracrine loops and are essential for decidualization, trophoblast growth and invasion. Since the dominant feature of early implantation is rapid trophoblast migration, particularly in primates, the degree to which the blastocyst attaches to the apical surface of the luminal endometrial epithelium during implantation is uncertain. The thickness of the glycocalyx on the uterine luminal epithelium during the peri-implantation period varies considerably between species. Its role in blastocyst attachment, if any, and in trophoblast cell locomotion, requires further study. The molecular properties and functions of the uterine epithelial plasma membrane, and those of the interacting trophoblast at the site of implantation, have been largely neglected and require further extensive study.

The effects of coculture with autologous cryopreserved endometrial cells on human in vitro fertilization and early embryo morphology: a randomized study

PURPOSE

The aim of this study was to examine the influence of endometrial cells on the fertilization rate and early embryonic morphology following routine in vitro fertilization (IVF). Cryopreservation with subsequent thawing allowed the use of autologous somatic cells, thus minimizing the risk of transmission of infective agents. Interpatient variability was eliminated by randomizing oocytes from each cycle into the control or coculture group.

RESULTS

Two hundred ninety-four oocytes from 24 IVF cycles (21 patients) were included in the study (145 coculture and 149 control). The normal fertilization rate of control oocytes (56.4%) was not significantly different from that of oocytes cocultured with endometrial cells (61.4%). The mean number of blastomeres in cocultured embryos (3.65) was not significantly different from the number in control embryos (3.46) 2 days after insemination, but the proportion of embryos with minimal or no fragmentation was significantly higher in the coculture group [34/84 (40.5%) vs. 17/80 (21.3%); P < 0.01].

CONCLUSIONS

The inclusion of cryopreserved autologous endometrial cells in routine clinical IVF procedures does not influence fertilization or the early cleavage rate but may reduce the extent of embryo fragmentation during the early cleavage divisions.

Luteinizing hormone/chorionic gonadotropin bioactivity in the common marmoset (Callithrix jacchus) is due to a chorionic gonadotropin molecule with a structure intermediate between human chorionic gonadotropin and human luteinizing hormone

Chorionic gonadotropin (CG), a pregnancy-specific heterodimeric hormone found in primates, is responsible for CL rescue with pregnancy maintenance. Of the primates, the human and baboon gene sequences are the only structures so far determined. In order to study the structure and function of CG in other primates, we have isolated and sequenced the coding regions for the two subunits of marmoset CG (mCG) by the reverse transcription/polymerase chain reaction method. Study of multiple clones confirmed a high degree of homology with the human sequences (88% and 80% for the alpha and beta nucleotide sequences, respectively). Marmoset CG alpha has an extra four amino acids compared to hCG alpha, whereas the mCG beta sequence has a 3-bp deletion that maintains the reading frame and C-terminal amino acid sequence. Most of the differences between hCG beta and mCG beta peptides occur in the C-terminal region, which includes the loss of two of the O-linked glycosylation consensus sequences and the presence of an N-linked glycosylation consensus sequence. When mCG alpha and beta were co-expressed in CHO cells, assembly of biologically active hormone was confirmed by induced steroid secretion by MA10 cells. Partially purified mCG beta was used to raise anti-mCG antibodies. To date, an antibody has been obtained that is capable of detecting recombinant mCG beta, recombinant mCG dimer, and mCG dimer secreted by cultured marmoset trophoblast. Marmoset CG alpha and beta were also detectable at the transcriptional level in cultured trophoblast by in situ hybridization. This suggests that the LH/CG bioactivity reported from marmoset placentae and embryos is due to a molecule with structural features common to hLH (glycosylation pattern) and hCG (CG beta C-terminal structure).

Differential distribution of mRNA for the alpha- and beta-subunits of chorionic gonadotrophin in the implantation stage blastocyst of the marmoset monkey

We studied the expression of mRNA encoding the alpha- and beta-subunits of marmoset chorionic gonadotrophin (mCG) in implantation stage blastocysts and in a trophoblastic cell line derived from such blastocysts. In this investigation in situ hybridization was carried out using digoxygenin-labelled riboprobes to localize the subunit transcripts. The trophoblastic cell line, known to secrete bioactive mCG, was used as a positive control. Marmoset uterine embryos were cultured to hatched blastocysts and following growth on Matrigel or plastic were processed for in situ hybridization at developmental stages ranging from 13-15 days post-conception. In serial sections mCG-beta mRNA was detected mainly in polar trophoblast. The mRNA for mCG-alpha was expressed more uniformly in polar and mural trophoblast. Transcripts for the beta-subunit were not expressed, or present as weak signals, in the inner cell mass (ICM) and endoderm. However, low levels of mRNA for mCG-alpha were detected in the ICM and visceral endoderm. We have concluded that mRNA for mCG-beta was primarily localized to patches of syncytiotrophoblast at the embryonic pole and sparsely distributed in mural trophoblast, while the transcripts for mCG-alpha were distributed more uniformly in differentiating cytotrophoblast and syncytium, and at much lower levels in ICM and early endoderm.

Culture of marmoset blastocysts on matrigel: a model of differentiation during the implantation period

BACKGROUND

The objective was to develop an experimental model for studying the differentiation of trophoblast and inner cell mass (ICM) during the early stages of implantation in primates.

METHODS

Marmoset monkey blastocytes were used in these studies. Ovulation was timed by plasma progesterone assays in ovarian cycles initiated by administering a luteolytic agent to mating marmosets. Embryos were recovered from the uterus usually at the eight-cell stage and cultured in minimum essential medium containing fetal calf serum, insulin, and transferrin. The embryos that formed hatched blastocysts by about day 11 after ovulation were transferred for further development in Matrigel-coated culture chambers. After 2, 4, and 6 days of development, two blastocysts were processed at each interval and serially sectioned for light and electron microscopy.

RESULTS

All blastocysts adhered to the Matrigel at their embryonic pole within 24 hours. Adherent polar cytotrophoblast was differentiating to syncytiotrophoblast at all time intervals, but syncytium was not detected in mural trophoblast until day 4 after attachment. By day 2 syncytial microvilli and processes had penetrated the Matrigel surface, whereas by days 4 and 6 cytotrophoblast that was differentiating to syncytiotrophoblast had invaded the matrix. Since all blastocysts maintained their structural integrity progressive differentiation of the ICM, endoderm and presumptive mesoderm was observed. A small amniotic cavity was observed at 2 days and by 6 days a distinct cavity separated polarized epiblast and amnion cells. Visceral and parietal endoderm were present at 2 days, and a completed primary yolk sac was observed by 4 days after attachment. In all blastocysts a basal lamina lined the inner surface of mural and polar trophoblast and the basal surface of the differentiating ICM.

CONCLUSIONS

The developmental time sequence of the cultured blastocysts closely resembled the time frame reported for marmoset embryos implanting in utero. An effective model for studying trophoblast invasion and differentiation of embryonic germ cell layers has been established.

Chorionic gonadotrophin secretion by human blastocysts

Abnormal embryos that arose in our in-vitro fertilization programme were cultured in serum-free minimum essential medium (MEM), and those that developed into blastocysts were cultured up to day 14 after fertilization to study the influence of various supplements on chorionic gonadotrophin (CG) secretion. Human cord serum, at a concentration of 1%, was found to be one of the most effective stimulants for initiating and maintaining CG production. A mixture of insulin+transferrin+selenium (ITS) stimulated CG secretion in serum-free MEM, although the output of hormone began to decline after approximately 3 days. Platelet-derived growth factor (PDGF) produced a similar response to ITS. Stimulation of blastocyst CG secretion in the absence of serum could also be induced with 8-bromo-cAMP. All stimulants were able to evoke CG secretion in day 7-8 blastocysts. These studies have shown that multiple factors were capable of inducing CG production by early blastocysts. On the basis of these and other studies it was postulated that receptors for insulin, transferrin and PDGF were expressed in preimplantation blastocysts.

The fertilization and development of mouse oocytes following cortical granule discharge in the presence of a protease inhibitor

The effect of leupeptin, a serine protease inhibitor, on the fertilization and development potential of oocytes stimulated to undergo cortical granule exocytosis has been investigated. An in-vitro bioassay system was used in which mouse oocytes were exposed to calcium ionophore, A23187, in the presence and absence of leupeptin, before their fertilization and development to the blastocyst stage was assessed. We have demonstrated that the presence of leupeptin in the incubation medium, at concentrations of 1 micrograms/ml and 10 micrograms/ml during the first 10 min of cortical granule exocytosis, reversed the ionophore-induced decrease in the capacity of oocytes to fertilize and develop to blastocysts. The induction of exocytosis of cortical granules by calcium ionophore was confirmed using fluorescence microscopy. Using this technique, we also confirmed that leupeptin did not inhibit ionophore-induced cortical granule exocytosis, thus supporting the contention that leupeptin acted upon released cortical exudate. It was concluded that leupeptin acted by inhibiting proteases released into the perivitelline space during the early stages of cortical granule exocytosis. Based on these results it was proposed that leupeptin could be used to prevent premature loss of fertility of human oocytes which are inadvertently activated under in-vitro conditions.

Primary structures of neuropeptides isolated from the corpora cardiaca of various cetonid beetle species determined by pulsed-liquid phase sequencing and tandem fast atom bombardment mass spectrometry

A peptide with the same retention time on gradient reversed-phase high-performance liquid chromatography was present in the corpora cardiaca of 5 scarabaeid beetles, subfamily Cetoniinae: the three fruit beetle species Pachnoda marginata, P. sinuata and P. aemulae and the two protea beetle species Trichostetha fascularis and T. albopicta. Crude corpora cardiaca material from P. sinuata had a small hypertrehalosaemic effect in American cockroaches and a very weak hyperlipaemic activity in migratory locusts. Injections into P. sinuata caused hypertrehalosaemia when a dose of 1.0 corpora cardiaca equivalents was injected. An identical neuropeptide was isolated, by RP-HPLC, and sequenced by pulsed-liquid phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal 5-oxopyrrolidine-2-carboxylic acid residue, as well as by collision-induced decomposition tandem fast atom bombardment mass spectrometry. The peptide is a blocked octapeptide: Glu-Leu-Asn-Tyr-Ser-Pro-Asp-TrpNH2, previously designated Mem-CC. The synthetic peptide is able to elicit haemolymph carbohydrates in P. sinuata upon injection of low doses. Activity studies using synthetic analogues of this peptide revealed that Tyr4 may be important for receptor recognition/binding. The peptide is synthesized in intrinsic cells of the corpus cardiacum as shown by in vitro incorporation of [3H]Trp and [14C]Tyr in Mem-CC.

Horse and marmoset monkey sperm bind to the zona pellucida of salt-stored human oocytes

The present study demonstrates that horse and marmoset monkey sperm can bind to the human zona of salt-stored oocytes that failed to fertilize in vitro. Marmoset monkey sperm are also able to penetrate the salt-stored human zona. In contrast, human sperm do not bind to the zona of either horse or marmoset monkey oocytes. These results suggest that human sperm binding to the zona pellucida is more strictly species-specific than it is for horse and marmoset monkey sperm. In contrast, horse and marmoset monkey sperm contain receptors recognized by the human zona.

Resistance of human follicular oocytes to parthenogenetic activation: DNA distribution and content in oocytes maintained in vitro

Sixty-nine human oocytes were subjected to various parthenogenetic stimuli but no activation was observed. Analysis of Feulgen-stained DNA (F-DNA) distribution and content showed anomalies of chromosomal material in 36% of oocytes at 24-75 h after retrieval. A significant loss of F-DNA was noticed in apparently normal metaphase II oocytes remaining in culture for 2-3 days.

Follicular fluid renin concentration and IVF outcome

Total renin protein concentration (TRC) was measured in stored follicular fluid (FF) samples from 42 women. Samples were selected according to their origin from follicles either without recovered ova ('empty', n = 38) or fertilized but with failed implantation ('failed', n = 36) or successful deliveries ('deliveries', n = 71). Ratios of number of embryos transferred to number of infants delivered were 2:1, 3:1 or 4:2 but 1:1 was not available. Non-parametric testing was applied to FF-TRC, volume and outcome. TRC was significantly higher in the delivery than the failed (P = 0.001) or empty (P = 0.002) categories. Assuming that the range of renin in failed follicles can identify the sub-population of unsuccessful follicles in the delivery category, then elevated FF-TRC was clearly associated with successful outcome. For individual women, the odds of infant delivery increased 17-fold as a function of average FF-TRC between 10,000 and 25,000 microIU/ml. For failed and delivery but not empty follicles, higher renin levels occurred in the smaller follicles, consistent with a burst of renin synthesis associated with the presence of an oocyte. The results suggest that FF-TRC relates to ovum viability with ovarian hyperstimulation and may have predictive use in IVF programmes.

Use of oocytes that failed to be fertilized in vitro to study human sperm-oocyte interactions: comparison of sperm-oolemma and sperm-zona pellucida binding, and relationship with results of IVF

A test for human sperm binding to the oolemma was developed with oocytes that failed to be fertilized in vitro. The zonae pellucidae of the oocytes were removed under a dissecting microscope by brief exposure to dilute HCl (pH 2.5-3.0) in 0.9% NaCl. The zona-free oocytes (ZFOs) were incubated with a mixture of equal numbers of motile sperm from men to be tested and fertile donors. The sperm was differentially labelled with fluorescein or rhodamine and the results expressed as a ratio of the number of test to control sperm bound to several ZFOs in order to control for variability in the ability of the oolemma to bind sperm. The number of sperm bound to the oolemma increased with time and sperm concentration. The sperm-oolemma binding ratio determined for 32 patients undergoing in vitro fertilization (IVF) was significantly correlated with the sperm-zona pellucida (ZP) binding ratio but was not correlated with other sperm tests. The sperm-oolemma binding ratio was also related to the IVF rate, but this was not significant if the sperm-ZP binding ratio was included in the logistic regression model. Only four of the 32 patients had failure of fertilization in vitro. The human sperm-oolemma binding test may be useful for studying the interaction between gametes, but the test is unlikely to be as useful clinically as the sperm-ZP binding test for predicting fertilization in vitro.

The potential of early human embryos to form blastocysts, hatch from their zona and secrete HCG in culture

Early embryos assessed to be unsuitable for transfer to patients or for cryopreservation were cultured either in minimum essential medium (MEM) or in synthetic human tubal fluid (HFT). A significantly higher percentage of embryos developed to blastocysts in MEM (26.5%) than in HTF (14.5%). Serum was not required for blastocyst formation nor for hatching in MEM. HTF containing 1% human cord serum failed to support blastocyst hatching. Haploid (monopronucleate) and diploid (bipronucleate) embryos formed blastocysts and hatched with a similar frequency but triploid (tripronucleate) embryos developed poorly. Human chorionic gonadotrophin (HCG) released by hatched and intrazonal blastocysts was detected between days 7 and 8 after fertilization. The mean total HCG produced by hatched blastocysts by day 14 was 19,500 mIU, but embryos trapped inside their zonae released a mean level of 1550 mIU. Serum was shown to stimulate the output of HCG from both hatched and intrazonal blastocyst tissues. Free beta- and alpha-subunits of HCG were not released by developing blastocysts, but low levels of beta-HCG were produced by some embryonic tissues between days 12 and 14 when degenerative changes were observed.

A sperm-zona pellucida binding test and in vitro fertilization

Sperm binding to the zona pellucida was studied in 106 in vitro fertilization (IVF) patients. Oocytes that failed to fertilize in vitro were inseminated with a mixture of equal numbers of test and fertile donor sperm differentially labeled with fluorescein or rhodamine to control for variability in the sperm-zona pellucida binding capacity of oocytes. The ratio of the number of test and control sperm bound to four to six zonae pellucidae was significantly correlated with sperm morphology, viability, motility, motility index, and normal intact acrosomes in semen. The sperm-zona pellucida binding ratio was the most significant factor related to IVF rates by logistic regression analysis. But the proportions of sperm with normal morphology and intact acrosomes in semen also were significant. In patients with less than 30% of sperm with normal morphology, there was a highly significant relationship between IVF rate and sperm-zona pellucida binding and a weaker relationship with sperm morphology. In conclusion, the sperm-zona pellucida binding ratio test is useful for predicting sperm fertilizing ability in vitro, particularly in men with poor sperm morphology.

Human sperm-zona pellucida binding, sperm characteristics and in-vitro fertilization

The number of sperm bound to the zona pellucida (ZP) were counted on 660 oocytes that failed to fertilize in vitro from 162 patients. Oocytes from clutches in which some fertilized had significantly more sperm bound to the ZP than did those from clutches in which all oocytes failed to fertilize. Oocytes from patients in whom all were not fertilized and no sperm bound to the ZP were able to bind normal fertile donor sperm after storage in ammonium sulphate solution. The number of sperm bound to the ZP was significantly related to the proportion of sperm with normal morphology and normal intact acrosomes in semen, sperm concentration inseminated, sperm motility and viability. The number of sperm bound to the ZP, sperm normal morphology, diagnosis of male infertility and sperm concentration in semen were significantly related to the fertilization rate by logistic regression analysis. Thus the number of sperm bound to the ZP is an indicator for IVF success and low binding appears to be more frequently associated with sperm defects than oocyte defects.

An analysis of human oocytes and follicles from stimulated cycles: oocyte morphology and associated follicular fluid characteristics

The aim of this study was to determine whether certain characteristics of the follicular biochemistry, previously shown by us to be associated with oocyte developmental capacity, also reflected differences in oocyte appearance, and to determine the range of oocyte characteristics induced by ovarian stimulation. A representative sample of 33 human oocytes and associated follicular fluids was obtained after a follicular growth period considered suitable for IVF. Individual follicular fluid protein and proteoglycan levels, and follicular volume were compared with the morphological characteristics of each oocyte. Oocytes which retained the germinal vesicle nuclear status after exposure to human chorionic gonadotrophin tended to occur in small follicles (less than or equal to 2 ml) and to be highly vacuolated and with characteristic predicted a low potential for cleavage. Among those oocytes which had progressed to MII nuclear maturity [in the medium (2.5-6.5 ml) and large (greater than or equal to 7 ml) volume follicles] the degree of oocyte vacuolation was negatively correlated with alpha 1-antitrypsin level, while the degree of organelle clumping was correlated with proteoglycan and immunoglobulin levels. Only five of the oocytes (15%) in this sample had follicular characteristics consistent with a normal potential for pregnancy. These MII oocytes occurred within the medium volume range, had low vacuolation levels, and a low degree of organelle clumping. In contrast, those oocytes with a low potential for cleavage based on their follicular biochemistry, showed high cytoplasmic vacuolation levels.

The surplus human embryo: its potential for growth, blastulation, hatching, and human chorionic gonadotropin production in culture

Early embryos that were unsuitable for transfer to patients or for cryopreservation were cultured either in a human tubal fluid (HTF) or a minimum essential medium (MEM). A significantly higher proportion of embryos developed to blastocysts in MEM (26.8%) than in HTF (14.5%). Approximately similar proportions of embryos formed blastocysts in MEM in the presence or absence of serum. The rate of embryo growth to blastocysts was similar in all media. Blastocyst hatching occurred in MEM + or - serum, but it failed to occur in HTF with serum. Released human chorionic gonadotropin (hCG) from hatched and intrazonal blastocysts was detected by day 8 after fertilization. The mean amount of hCG produced by day 14 was 19,500 mIU from hatched and 1,550 mIU from intrazonal blastocysts. Serum stimulated the output of hCG.