[Possible applications of poultry immunoglobulins focusing on mycotoxin environmental loads and human influence]. / Baromfi-immunglobulinok lehetséges alkalmazásai a mikotoxin-környezetterhelések és a humánérintettség fókuszában.

In addition to their role, immunoglobulins can be used in animal and human diagnostic (immunoassay-based) measurements, prophylaxis and (immuno)therapy. For these purposes, today's "alternative" that is advantageous from an animal ethical point of view is the bird immunoglobulin Y isolated from egg yolk. Its development and production are cost-effective, the complexity is low, and due to its advantageous properties, it can be used in assays or even more so in medical therapies (primarily passive immunization). It is widely used (against pathogens or their toxins) in treatments of intestinal or metabolic diseases and inflammations. Its application in human diagnostics is limited, some markers are measured using immunoglobulin Y as assay component. In this study, a possible application, which is less common today, is presented. The problem of environmental impacts is becoming significant. Due to human activities, industrialization, environmental changes increase the appearance of natural environmental pollutants, including the effects of mycotoxins produced by molds locally and/or globally, which (mainly through nutrition) affect humans. Such agents often appear together, several mycotoxins affect the individual. As a result of their persistence, mycotoxins absorbed in the intestinal tract and accumulated in organs, can already reach levels that can cause physiological and/or behavioral effects. Although the examination of sources (contaminated foods) is regulated by law, the extent of accumulation has not been or cannot be examined and is often insufficiently taken into account. Due to the nature of the technique, the anti-mycotoxin avian immunoglobulin Y could be used both for detection of (deposited) mycotoxin(s) and/or even for immunotherapy (e.g., mycotoxin neutralization). Demonstrating the endocrine-disrupting mycotoxins using the example of zearalenone (with an explanation of its reproductive and immunological effects), we present generation of zearalenone (and mycotoxin-specific) avian immunoglobulin developments, advocate its use in human detection, urging the development of measurements that are suitable for detecting (multiple) accumulation. Orv Hetil. 2023; 164(39): 1527-1536.

Effect of ad libitum feeding of Holstein Friesian calves on immunological parameters and molecular stress on a transcriptional level.

Our aim was to compare the health and performance of ad libitum (ADLIB) and restrictedly fed Holstein Friesian heifer calves. Calves were selected to ADLIB (n = 13) and control (n = 13) groups randomly. The period of ADLIB feeding lasted for 3 weeks after colostrum supplementation. The calves in the control group received the same milk replacer, which was supplied according to the restrained feeding schedule of the farm. There was no difference between the two groups in weight, weight gain or movement activity, furthermore in the values of glucose, albumin, total protein, BHB, AST, oxidant and antioxidant status incl. dROM, PAT and OSI. The IL8 gene had higher levels (non significant, p > 0.05) of expression in the ADLIB group during the first 20 days of life, which indicates that ADLIB feeding might potentiate a stronger immune response to environmental stress. The IGF1 gene showed increased expression in the ADLIB fed group at almost all time points, however the difference was already detected on the first day of the study, indicating the importance of individual differences even within the same breed. During the first 10 days INS expression was higher in the restricted group, followed by a shift by day 20 and after, when the ADLIB group showed a higher relative expression level. The observed values describe a trend that, although not significant (p > 0.05), would seem to indicate that ADLIB feeding might potentiate a stronger immune response to environmental stress.

Hungarian indigenous Tsigai, a promising breed for excellent heat tolerance and immunity.

The adverse effects of climate change on sheep farming have become more noticeable in recent decades. Extensive efforts have been made to untangle the complex relationship between heat tolerance, animal health, and productivity, also to identify a resilient and economically suitable breed for selection that can be resilient to future climate change conditions. Using quantitative real-time polymerase chain reaction (qRT-PCR), we observed the seasonal variations in the expression of several important genes related to heat stress and immunity (HSP70, IL10, TLR2, TLR4, and TLR8) in three of the most widely kept sheep breeds in Hungary: The indigenous Tsigai, Hungarian Merino, and White Dorper. We found that the seasonal stressor affected the relative gene expression of all genes in this study. Notably, The Hungarian indigenous Tsigai was the most robust breed adapted to the Hungarian continental (hot summer, cold winter) environment, with excellent thermotolerance and immunity. Furthermore, despite suffering from heat stress in the summer, Hungarian Merino maintained their robust immune system well throughout the year.

Hydrogen peroxide production by epidermal dual oxidase 1 regulates nociceptive sensory signals.

Keratinocytes of the mammalian skin provide not only mechanical protection for the tissues, but also transmit mechanical, chemical, and thermal stimuli from the external environment to the sensory nerve terminals. Sensory nerve fibers penetrate the epidermal basement membrane and function in the tight intercellular space among keratinocytes. Here we show that epidermal keratinocytes produce hydrogen peroxide upon the activation of the NADPH oxidase dual oxidase 1 (DUOX1). This enzyme can be activated by increasing cytosolic calcium levels. Using DUOX1 knockout animals as a model system we found an increased sensitivity towards certain noxious stimuli in DUOX1-deficient animals, which is not due to structural changes in the skin as evidenced by detailed immunohistochemical and electron-microscopic analysis of epidermal tissue. We show that DUOX1 is expressed in keratinocytes but not in the neural sensory pathway. The release of hydrogen peroxide by activated DUOX1 alters both the activity of neuronal TRPA1 and redox-sensitive potassium channels expressed in dorsal root ganglia primary sensory neurons. We describe hydrogen peroxide, produced by DUOX1 as a paracrine mediator of nociceptive signal transmission. Our results indicate that a novel, hitherto unknown redox mechanism modulates noxious sensory signals.

Restrained expression of canine glucocorticoid receptor splice variants α and P prognosticates fatal disease outcome in SIRS.

Glucocorticoids play a central role in the inflammatory response and alleviate the symptoms in critically ill patients. The glucocorticoid action relies on the glucocorticoid receptor (GR) which translocates into the nucleus upon ligand-binding and regulates transcription of a battery of genes. Although the GR is encoded by a single gene, dozens of its splice variants have been described in diverse species. The GRα isoform encodes the full, functionally active protein that is composed of a transactivation, a DNA-binding, and a C-terminal ligand-binding domain. The second most highly expressed receptor variant, the GR-P, is formed by an intron retention that introduces an early stop codon and results in a probably dysfunctional protein with truncated ligand-binding domain. We described the canine ortholog of GR-P and showed that this splice variant is highly abundant in the peripheral blood of dogs. The level of cGRα and cGR-P transcripts are elevated in patients of SIRS and the survival rate is increased with elevated cGRα and cGR-P expression. The ratio of cGRα and cGR-P mRNA did not differ between the survivor and non-survivor patients; thus, the total GR expression is more pertinent than the relative expression of GR isoforms in assessment of the disease outcome.

Characterisation of eGFP-transgenic BALB/c mouse strain established by lentiviral transgenesis.

Lentiviral technology is a powerful tool for the creation of stable transgenic animals. However, uncertainties have remained whether constitutive promoters resist long-term silencing. We used concentrated HIV-1 based lentiviral vectors to create stable transgenic BALB/c mice by perivitelline injection. In our vectors eGFP expression was driven by the human EF1alpha promoter. The established transgenic animals were analyzed for eGFP expression by in vivo fluorescence imaging, PCR, histology and flow-cytometry. eGFP expression showed even distribution without mosaicism; however, tissue-dependent differences of eGFP expression were observed. Up to the sixth generation only one newborn showed eGFP inactivation. eGFP + transgenic bone marrow cells efficiently provided long-term haemopoietic repopulation in radiation chimeras, regenerating all bone marrow-derived lineages with eGFP + cells with distinct eGFP expression profiles. The established eGFP + BALB/c mouse strain is expected to be extremely useful in various immunological experiments.

Placenta-specific gene manipulation in rabbits.

Lentiviral gene constructs can be efficiently and specifically delivered to trophoblast cell lineages in rodents. In vivo genetic manipulation of trophoblast cell lines enables functional and developmental studies in the placenta. In this report we show that genetic modification can be produced in the extraembryonic tissues of rabbits by lentiviral gene constructs. When 8-16 cell stage embryos were injected with lentiviral particles, strong reporter gene expression resulted in the rabbit placenta. The expression pattern displayed some mosaicism. A strikingly high degree of mosaic GFP expression was detected in some parts of the yolk sac, which is a hypoblast-derived tissue. Whereas expression of the reporter gene construct was detected in placentas and yolk sacs, fetuses never expressed the transgene. As rabbits are an ideal model for functional studies in the placenta, our method would open new possibilities in rabbit biotechnology and placentation studies.

Position independent and copy-number-related expression of the bovine neonatal Fc receptor alpha-chain in transgenic mice carrying a 102 kb BAC genomic fragment.

We generated and characterized transgenic mice carrying a 102 kb bovine genomic fragment, encoding the neonatal Fc receptor alpha-chain (bFcRn). FcRn plays a crucial role in the maternal IgG transport and it also regulates the IgG and albumin homeostasis. Some of its functions and transcriptional regulation show species specific differences. The FcRn heterodimer is composed of the alpha-chain and beta-2-microglobulin (beta2 m). A bacterial artificial chromosome containing the bovine FcRn alpha-chain gene (bFCGRT) with its 44 kb 5' and 50 kb long 3' flanking sequences was microinjected into fertilized mouse oocytes. Two of the transgenic lines generated, showed copy number related and integration site independent bFcRn expression. The bFcRn alpha-chain forms a functional receptor with the mouse beta2-microglobulin and extends the half-life of the mouse IgG in transgenic mice. Our results underline the feasibility of creating BAC transgenic mouse models of economically important bovine genes.

Analysis of the efficiency of the rabbit whey acidic protein gene 5' flanking region in controlling the expression of homologous and heterologous linked genes.

For 10 years, the regulatory regions of the mouse and rabbit whey acidic protein gene have been used to express heterologous proteins in the milk of transgenic mice, as well as to produce pharmaceutical proteins, on a large scale, in the milk of transgenic livestock. To date, a broad range of expression levels have been detected, and elucidation of the structure-function relationship in these regulatory regions might help to achieve high levels of expression, reproducibly. An extended 5' regulatory region (17.6 kb v. 6.3 kb) of the rabbit whey acidic promoter resulted in an increased frequency of rabbit whey acidic protein expression in transgenic mice. However, the expression levels were low compared with the high expression levels achieved in both transgenic mice and rabbits using the heterologous kappa-casein in the 6.3 kb rabbit whey acidic protein 5' regulatory region. These results underline the importance of the 3' downstream regulatory regions, which still need to be better characterized in the whey acidic protein gene.

Production of transgenic chimeric rabbits and transmission of the transgene through the germline.

Here we report that improved reproductive technologies combined with an efficient microinjection method and in vitro cultivation medium enabled us to create germ line chimeric rabbits. To follow the fate of the chimeric embryo a blastomere marked with the human blood coagulation factor VIII (hFVIII) transgene was microinjected into a morula stage wild type embryo. The degree of chimerism in different tissues was estimated by real-time PCR and was found to be in the range of 0.1-42%. Among the four chimeric animals, one was identified as a chromosomal intersex and two were germline chimeras.