Genetic and environmental determinants of Immunoglobulin G in kid serum and adult colostrum of dairy goats

Immune competence is a key factor in the health and resilience of dairy ruminants. The aim of this study was to study immunoglobulin G concentration in serum shortly after birth and in colostrum of lactating animals as proxy of passive immune transfer and colostrum quality, respectively, and thus provide new health and resilience indicators for selection. Data from 424 female kids and 203 primiparous goats, reared on an INRAE experimental farm, were analyzed. IgG concentration was measured in kid serum and goat colostrum, respectively, using the radial immunodiffusion technique. Linear models were used to identify factors of variation in serum and colostrum IgG concentration, and health events were monitored for 5 weeks after birth to measure the impact of passive immune transfer on kids' health. We found a significant effect of serum IgG level on hindquarters cleanliness score (as a proxy of digestive troubles) and nasal and ocular discharge. As expected, the absorption of IgG in the days following birth is essential to ensure the passive transfer of immunity from the mother to the youngster, and provide immune protection. Genetic parameters were estimated for serum IgG concentration in kids and for colostrum characteristics in primiparous goats. Heritability of serum IgG in kids was not significantly different from zero. This low value, with large SE, may be due to the limited sample size and large environmental variability likely not accounted for. Especially, we could not adjust for the amount of IgG that was ingested by the kid, which can have a significant effect on serum IgG and possibly on heritability estimates. Heritability of colostrum traits were moderate, with estimates of 0.25 (±0.16), 0.35 (±0.16), and 0.25 (±0.16) for IgG concentration, IgG mass and colostrum volume, respectively. Genetic correlations with milk production showed high standard errors due to small numbers. However, estimates suggest a negative genetic association between production and IgG concentration in colostrum (rg = -0.44 ± 0.33), probably linked to a positive association with total colostrum volume. The significant heritabilities that were estimated for the first time demonstrate the existence of genetic control of colostrum quality in goats, and open up opportunities for selection in this species.

Tetanus prophylaxis in horses: guidelines for New Zealand and Australia based on a critical appraisal of the evidence

Horses are exquisitely sensitive to tetanus neurotoxin and are exposed to the risk of infection with Clostridium tetani throughout life. The vaccine against tetanus is highly effective at preventing disease, whereas tetanus in unvaccinated populations is associated with high mortality rates. Current guidelines in New Zealand and Australia for the available vaccine contain contradictions and limitations surrounding the optimal tetanus immunisation protocols for both adult horses and foals. This review critically evaluates the scientific literature on tetanus prophylaxis in horses within the context of equine practice and available products in New Zealand and Australia. The review was conducted by a panel of industry and specialist veterinarians to obtain agreement on nine equine tetanus prophylaxis guidelines for practising veterinarians. The primary protocol for tetanus toxoid (TT) immunisation consists of a three-dose series IM for all horses ≥ 6 months of age, and a four-dose series IM is proposed if commencing vaccination in foals between 3 and 6 months of age. Tetanus prophylaxis in foals < 3 months of age relies on passive immunity strategies. Following the completion of the primary protocol, a TT booster dose IM should be administered within 5 years, and every 5 years thereafter. When followed, these protocols should provide adequate protection against tetanus in horses. Additional tetanus prophylaxis guidelines are provided for veterinarians attending a horse experiencing a known "risk event" (e.g. wound, hoof abscess, surgery, umbilical infection). When a correctly vaccinated horse experiences a risk event, pre-existing immunity provides protection against tetanus. When an unvaccinated horse or one with unknown vaccination status, or a foal born to an unvaccinated dam, experiences a risk event, TT IM and tetanus antitoxin (TAT) 1,500 IU SC should be administered simultaneously at separate sites, and the TT primary immunisation protocol should subsequently be completed for the horse's respective age. In previously immunised pregnant broodmares, a TT booster dose administered 4-8 weeks prior to parturition optimises the transfer of passive immunity against tetanus to the newborn foal via colostrum; provided that post-natal IgG concentration in serum is > 800 mg/dL (8 g/L), such foals should be passively protected against tetanus up to 6 months of age. Survivors of clinical tetanus must still receive the primary protocol for vaccination against tetanus. In summary, all horses in New Zealand and Australia should be vaccinated against tetanus with protection maintained throughout life via TT booster doses, facilitated by accurate medical record keeping and client education.

Arthropods to Eutherians: A Historical and Contemporary Comparison of Sparse Prenatal Microbial Communities Among Animalia Species

Since the advent of next-generation sequencing, investigators worldwide have sought to discern whether a functional and biologically or clinically relevant prenatal microbiome exists. One line of research has led to the hypothesis that microbial DNA detected in utero/in ovo or prior to birth/hatching is a result of contamination and does not belong to viable and functional microbes. Many of these preliminary evaluations have been conducted in humans, mice, and nonhuman primates due to sample and specimen availability. However, a comprehensive review of the literature across animal species suggests organisms that maintain an obligate relationship with microbes may act as better models for interrogating the selective pressures placed on vertical microbial transfer over traditional laboratory species. To date, studies in humans and viviparous laboratory species have failed to illustrate the clear presence and transfer of functional microbes in utero. Until a ground truth regarding the status and relevance of prenatal microbes can be ascertained, it is salient to conduct parallel investigations into the prevalence of a functional prenatal microbiome across the developmental lifespan of multiple organisms in the kingdom Animalia. This comprehensive understanding is necessary not only to determine the role of vertically transmitted microbes and their products in early human health but also to understand their full One Health impact. This review is among the first to compile such comprehensive primary conclusions from the original investigator's conclusions, and hence collectively illustrates that prenatal microbial transfer is supported by experimental evidence arising from over a long and rigorous scientific history encompassing a breadth of species from kingdom Animalia.

The role of hormones in the regulation of lactogenic immunity in porcine and bovine species

Colostrum and milk offer a complete diet and vital immune protection for newborn mammals with developing immune systems. High immunoglobulin levels in colostrum serve as the primary antibody source for newborn piglets and calves. Subsequent milk feeding support continued local antibody protection against enteric pathogens, as well as maturation of the developing immune system and provide nutrients for newborn growth. Mammals have evolved hormonal strategies that modulate the levels of immunoglobulins in colostrum and milk to facilitate effective lactational immunity. In addition, hormones regulate the gut-mammary gland-secretory immunoglobulin A (sIgA) axis in pregnant mammals, controlling the levels of sIgA in milk, which serves as the primary source of IgA for piglets and helps them resist pathogens such as PEDV and TGEV. In the present study, we review the existing studies on the interactions between hormones and the gut-mammary-sIgA axis/lactogenic immunity in mammals and explore the potential mechanisms of hormonal regulation that have not been studied in detail, to draw attention to the role of hormones in influencing the immune response of pregnant and lactating mammals and their offspring, and highlight the effect of hormones in regulating sIgA-mediated anti-infection processes in colostrum and milk. Discussion of the relationship between hormones and lactogenic immunity may lead to a better way of improving lactogenic immunity by determining a better injection time and developing new vaccines.

Efficacy of oral administration of specific immunoglobulins in preventing neonatal calf diarrhoea in dairy herds

BACKGROUND

The aim of this study was to evaluate the efficacy of bovine concentrated lactoserum (BCL) containing specific immunoglobulin G against Escherichia coli, rotavirus and coronavirus in preventing neonatal calf diarrhoea (NCD).

METHODS

A total of 489 newborn calves from 35 herds were orally given either BCL or a placebo before the first feeding of colostrum and clinically supervised by the farmers for the first 14 days of life. The diarrhoea score was defined according to the following criteria: 0 = no diarrhoea; 1 = light diarrhoea without medical treatment; 2 = diarrhoea requiring oral treatment (rehydration and/or antibiotic therapy); and 3 = severe diarrhoea requiring parenteral rehydration or resulting in death.

RESULTS

A total of 138 calves suffered from diarrhoea (28%), and 65 (13%) showed signs of diarrhoea requiring treatment. The odds of getting NCD were reduced (odds ratio = 0.326; p < 0.001) in the BCL group. There was a tendency towards a reduction in the duration of NCD in the BCL group (2.25 (±1.7) days vs. 2.88 (±2.7) days in the placebo group) (p = 0.052). Furthermore, no calves died in the BCL group, whereas four calves died in the placebo group.

LIMITATIONS

Because of the design of the study using animals in practice, the mechanisms explaining the clinical findings remain as hypotheses. Diarrhoea scoring performed by farmers has to be analysed and interpreted with caution.

CONCLUSIONS

This study demonstrates that BCL as a single preventive treatment is effective in reducing the incidence of NCD even in a region with good general management of dairy calves and overall good colostrum quality.

Factors Affecting Gut Microbiota of Puppies from Birth to Weaning

The review described the most important factors affecting the development of the intestinal microbiota in puppies from birth to weaning. The health and well-being of the microbiome in puppies is influenced by the type of parturition, the maternal microbiota, and the diet of the mother, directly or indirectly. The isolation of bacteria in dogs from the placenta, fetal fluids, and fetuses suggests that colonization could occur before birth, although this is still a matter of debate. Accordingly, newborn puppies could harbor bacteria that could be of maternal origin and that could influence microbial colonization later in life. However, the long-term impacts on health and the clinical significance of this transfer is not yet clear and needs to be investigated. The same maternal bacteria were found in puppies that were born vaginally and in those delivered via cesarean section. Potentially, the relationship between the type of parturition and the colonization of the microbiome will influence the occurrence of diseases, since it can modulate the gut microbiome during early life. In addition, puppies' gut microbiota becomes progressively more similar to adult dogs at weaning, as a consequence of the transition from milk to solid food that works together with behavioral factors. A number of researches have investigated the effects of diet on the gut microbiota of dogs, revealing that dietary interference may affect the microbial composition and activity through the production of short-chain fatty acids and vitamins. These compounds play a fundamental role during the development of the fetus and the initial growth of the puppy. The composition of the diet fed during pregnancy to the bitches is also an important factor to consider for the health of newborns. As far as it is known, the effects of the type of parturition, the maternal microbiota, and the diet on the microbial colonization and the long-term health of the dogs deserve further studies. Definitely, longitudinal studies with a larger number of dogs will be required to assess a causal link between microbiome composition in puppies and diseases in adult dogs.

Genetic Parameters of Serum Total Protein Concentration Measured with a Brix Refractometer in Holstein Newborn Calves and Fresh Cows

The objective was to estimate the genetic parameters of serum total protein concentration in newborn calves (calfSTP) and post parturient dairy cows (cowSTP). The study included 1013 calves and 989 cows from 10 dairy farms. Calf blood samples were collected 24-48 h after parturition while cow blood and colostrum samples were collected in the first 24 h after calving. Blood serum total protein and colostrum total solids content were determined using a Brix refractometer. Chemical analysis of colostrum was performed with Milkoscan. Univariate mixed linear models were used to estimate the heritability of calfSTP and cowSTP and their genetic and phenotypic correlations with colostrum traits. The heritability estimates of calfSTP and cowSTP were 0.21 and 0.20 (p < 0.05), respectively. Strong genetic correlations (r > 0.90) were detected between calfSTP and colostrum total solids and protein content (p < 0.05). Corresponding phenotypic correlations were 0.31-0.33 (p < 0.05). No genetic or phenotypic correlations were detected with colostrum fat content while the respective correlations with lactose were negative (-0.82 and -0.19, p < 0.05). No genetic correlations were detected between cowSTP and colostrum traits and only a low negative phenotypic one with lactose was detected. The results confirm that genetic selection aiming to improve the passive transfer of immunity in newborn calves and general fresh cow health would be feasible.

Effect of seaweed feeding before calving on colostral IgA concentration in Japanese Black cows

In this study, we investigated the effect of feeding seaweed to Japanese Black cows before calving on IgA concentrations in colostrum. Seven Japanese Black breeding cows were used as test animals, with three cows in the seaweed-fed group (seaweed group) and four in the seaweed-non-fed group (control group). Each cow was fed 6 kg of sudangrass hay and 2.5 kg of compound feed twice daily (09:00 a.m. and 04:00 p.m.) as basal diets. Both groups had free access to water. In the seaweed group, commercially available seaweed feed was fed from 2 months before calving until the day of calving. The seaweed of 150 g/head/day was added to the basal diet at the morning feeding. Colostrum collected immediately after calving was used to measure IgA concentrations by ELISA. The IgA concentration in colostrum was significantly higher in the seaweed group than in the control group (P < 0.05). This suggested that feeding seaweed to Japanese Black cows before calving may increase IgA concentration in colostrum.

Impact of prepartum administration of a vaccine against infectious calf diarrhea on nonspecific colostral immunoglobulin concentrations of dairy cows

Passive transfer of colostral immunoglobulins from the cow to the calf is essential for calf health. The objective of this study was to determine if prepartum administration of a vaccine stimulates increased concentrations of colostral immunoglobulins of dairy cows beyond what is explained by vaccine-specific immunoglobulins. A prospective cohort study was conducted on a spring-calving commercial dairy farm that had a policy of only vaccinating cows with even ear tag numbers with a calf diarrhea vaccine, while cows with odd ear tag numbers were left unvaccinated. Cows in the vaccinated group (even ear tag numbers, n=204) received a sensitizer and booster vaccination with a vaccine against bovine rotavirus (serotypes G6 and G10), bovine coronavirus and E. coli having the K99 pili adherence factor. A sensitizer was given because the study vaccine was different to the vaccine previously used. Cows in the control group (odd ear tag numbers, n=194) received a 2 mL subcutaneous sterile saline solution. Both groups received two treatments at a three-week interval, completing the treatments approximately two weeks prior to the planned start of calving. During the calving period, technicians separated calves from cows immediately after parturition and prior to suckling, and cows were completely milked out within six hours of parturition. Vaccine-specific, total, and nonvaccine-specific (total minus vaccine-specific) concentrations of immunoglobulin classes A, G1, G2a and M (IgA, IgG1, IgG2a and IgM respectively) were quantified by mass spectrometry for 20 colostrum samples from each treatment group. Predicted mean non-vaccine-specific colostral IgM concentrations were 8.76 (95% CI =7.18-10.67) and 5.78 (95% CI =4.74-7.05) mg/ml for vaccinated and control cows respectively (p =0.005). Predicted mean non-vaccine-specific colostral IgG1 concentrations were 106.08 (95% CI =92.07-120.08) and 95.30 (95% CI =81.30-109.31) mg/ml among vaccinated and control cows respectively, however these means were not significantly different (p=0.278). It is thus possible that the vaccine, in addition to specifically managing infectious calf diarrhea, may also have non-specific benefits by improving colostrum quality through increased non-vaccine-specific colostrum IgM concentrations. Further research is necessary to determine the mechanism for these preliminary findings, whether the effect may occur in other immunoglobulin classes, and what impacts it may have on calf health outcomes.

Supplementing Mannan Oligosaccharide Reduces the Passive Transfer of Immunoglobulin G and Improves Antioxidative Capacity, Immunity, and Intestinal Microbiota in Neonatal Goats

Successful establishment of passive immunity (PIT) and regulation of intestinal microbiota are crucial for ruminants to maintain body health and reduce the risk of disease during the neonatal period. Thus, the objective of this study was to investigate the effects of mannan oligosaccharide (MOS) supplementation on passive transfer of immunoglobulin G (IgG), serum inflammatory cytokines and antioxidant levels as well as bacteria composition in the ileal digesta. A total of 14 healthy neonatal Ganxi black goats with similar birth weight (BW: 2.35 ± 0.55 kg) were selected and allocated into two groups, only fed colostrum and milk replacer (CON, n = 7) and supplemented MOS (0.06% of birth BW) in the colostrum and milk replacer (MOS, n = 7). The results indicated that MOS supplementation significantly reduced (p < 0.05) serum IgG level at 3 and 6 h after colostrum feeding. Serum GLP-1 level of goats in the MOS group was significantly lower (p = 0.001) than that in the CON group. Goats in the MOS group had higher serum CAT and lower MDA level than those in the CON group (p < 0.05). Serum anti-inflammatory cytokine level of interleukin 4 (IL-4) was increased (p < 0.05), while pro-inflammatory cytokine IL-6 level was reduced (p < 0.05) in the MOS group when compared with the CON group. In addition, MOS supplementation remarkably increased (p < 0.05) the level of secretory IgA (sIgA) in the ileal digesta. Principal coordinate analysis of 16S rRNA sequence based on Brinary jaccard, Bray curtis, and weighted UniFrac distance of ileal microbiota showed a distinct microbial differentiation between the CON and MOS groups (p < 0.05). The relative abundance of Firmicutes in the MOS group was higher than that in the CON group, while the abundance of Verrucomicrobia was lower in the MOS group than that in the CON group at the phylum level (p < 0.05). The relative abundance of Proteobacteria tended to decrease (p = 0.078) in the MOS group at the phylum level. The results of LEfSe analysis showed that MOS group was characterized by a higher relative abundance of Lactobacillus, while the CON group was represented by a higher relative abundance of Akkermansia and Ruminiclostridium_5. Our findings demonstrated that MOS supplementation during the neonatal period increases antioxidant capacity and reduces the inflammatory response, and promotes IgA secretion and Lactobacillus colonization in the ileum. Thus, MOS induced positive effects are more pronounced in neonatal goats that might be an effective approach to maintain intestinal health and improve the surviving rate of neonatal ruminants.

Early Influences of Microbiota on White Matter Development in Germ-Free Piglets

Abnormalities in the prefrontal cortex (PFC), as well as the underlying white matter (WM) tracts, lie at the intersection of many neurodevelopmental disorders. The influence of microorganisms on brain development has recently been brought into the clinical and research spotlight as alterations in commensal microbiota are implicated in such disorders, including autism spectrum disorders, schizophrenia, depression, and anxiety via the gut-brain axis. In addition, gut dysbiosis is common in preterm birth patients who often display diffuse WM injury and delayed WM maturation in critical tracts including those within the PFC and corpus callosum. Microbial colonization of the gut aligns with ongoing postnatal processes of oligodendrogenesis and the peak of brain myelination in humans; however, the influence of microbiota on gyral WM development remains elusive. Here, we develop and validate a neonatal germ-free swine model to address these issues, as piglets share key similarities in WM volume, developmental trajectories, and distribution to humans. We find significant region-specific reductions, and sexually dimorphic trends, in WM volume, oligodendrogenesis, and mature oligodendrocyte numbers in germ-free piglets during a key postnatal epoch of myelination. Our findings indicate that microbiota plays a critical role in promoting WM development during early life when the brain is vulnerable to environmental insults that can result in an array of disabilities manifesting later in life.

Comparative proteome profiling in exosomes derived from porcine colostrum versus mature milk reveals distinct functional proteomes

Exosomes are membranous vesicles of endocytic origin, recently been considered as major players in cell-cell communication. Milk is highly complex, and diverse biocomponents provide adequate nutrition, transfer immunity, and promote adequate neonate development. Milk exosomes are suggested to have a key role in these processes, yet to be further explored, and the alteration of the exosomes' cargo in different stages of lactation stages is important for understanding the factors relevant in nursing and also for improving milk replacer products both for humans and animals. We isolated exosomes from porcine milk in different lactation stages and analyzed their content using a TMT-based high-resolution quantitative proteomic approach. Exosomes were isolated using ultracentrifugation coupled with size exclusion chromatography to enrich milk-derived exosomes in samples obtained at day 0, 7, and 14 after parturition, and characterized by nanoparticle tracking analysis, transmission electron microscopy, and Western blotting. Quantitative proteomics analysis revealed different proteome profiles for colostrum exosomes and milk exosomes. The functional analysis highlighted pathways related to the regulation of homeostasis to be upregulated in colostrum exosomes, and pathways such as endothelial cell development and lipid metabolism to be upregulated in mature milk exosomes. This study endorses the importance of exosomes as active biocomponents of milk and provides knowledge for future studies exploring their role in the regulation of immunity and growth of the newborn. SIGNIFICANCE: The identified functional proteome and protein-protein interaction networks identified in our study help to elucidate the role of milk exosomes in different lactation periods. The results generated herein are of relevance for the basic understanding of their impact on the infant's development but also for bringing forward the manufacturing of milk replacers.

Impact of Type of Parturition on Colostrum Microbiota Composition and Puppy Survival

Simple Summary

It has long been believed that the bacteria present in milk and colostrum were due to contamination during suckling from the oral cavity of the newborn or the skin of the mother. Colostrum and meconium from newborns were considered sterile. In the last decade, human research has provided evidence that bacteria are present in colostrum, milk, placenta, and the intestine of the newborn. The colostrum microbiota appears to change greatly and very rapidly, and in humans it has been found that it can be influenced by the type of parturition. Because information on the colostrum microbiota in dogs is lacking, the objective of our study was to determine whether the type of parturition affects the colostrum microbiota and the growth and survival of puppies in early life. Bacteria isolated from maternal colostrum and puppies meconium were identified by mass spectrometry. The results of this study provide new information on the colostrum microbiome of healthy dams and suggest that the type of parturition influences the bacterial composition of the colostrum microbiota, which may be an important factor in weight gain and survival of puppies in early life.

Abstract

The objective of our study was to determine whether the type of parturition affects the microbiota of the colostrum and the growth and survival of the puppies. Seventy-nine newborn puppies were divided into three groups regarding the type of parturition: vaginal delivery (VD), elective caesarean section (EL-CS), and emergency caesarean section (EM-CS). After the birth of the puppies, swabs of meconium were collected from the puppies and colostrum was obtained from the dam. Many aerobic and anaerobic bacteria were isolated and identified by mass spectrometry (MALDI-TOF MS). The colostrum microbiota of VD and EL-CS puppies contained a significantly higher abundance of bacteria belonging to the genera Staphylococcus, Kocuria and Enterococcus compared with EM-CS colostrum samples. The composition of the meconium microbiota of the puppies present at birth was similar to the colostrum microbiota of their mothers. It was also found that puppies without a meconium microbiota at birth gained weight more slowly compared with puppies with a meconium microbiota at birth. The type of parturition influenced the bacterial composition of the microbiota in the colostrum. Future studies are necessary to further define the significance of the observed differences in microbiota composition between EM-CS compared with EL-CS and VD colostrum microbiota.

Methodological Considerations for Assessing Immune Defense in Reproductive Females

One of the key foci of ecoimmunology is understanding the physiological interactions between reproduction and immune defense. To assess an immune challenge, investigators typically measure an immune response at a predetermined time point that was selected to represent a peak response. These time points often are based on the immunological responses of nonreproductive males. Problematically, these peaks have been applied to studies quantifying immune responses of females during reproduction, despite the fact that nonreproductive males and reproductive females display fundamentally different patterns of energy expenditure. Previous work within pharmacological research has reported that the response to the commonly-used antigen keyhole limpet hemocyanin (KLH) varies among individuals and between females and males. In this heuristic analysis, we characterize antibody responses to KLH in females with varying reproductive demands (nonreproductive, lactating, concurrently lactating, and pregnant). Serum was taken from one animal per day per group and assessed for general and specific Immunoglobulins (Igs) G and M. We then used regression analysis to characterize the antibody response curves across groups. Our results demonstrate that the antibody response curve is asynchronous among females with varying maternal demands and temporally differs from the anticipated peak responses reflected in standardized protocols. These findings highlight the importance of multiple sampling points across treatment groups for a more integrative assessment of how reproductive demand alters antibody responses in females beyond a single measurement.

Determination of immunoglobulin concentrations and genetic parameters for colostrum and calf serum in Charolais animals

Colostrum samples from 366 Charolais primiparous cows, as well as serum from their calves at 24 to 48 h of age, were collected to gain an overview of the situation regarding passive immune transfer in beef cattle, from both the phenotypic and genetic points of view. All samples were analyzed to quantify their G₁ immunoglobulins by radial immunodiffusion (RID) and their IgG, IgA, and IgM using ELISA. The average concentrations obtained in colostrum were 84 mg/mL for RID-IgG₁, and 158 mg/mL, 4.5 mg/mL and 10.8 mg/mL for ELISA-IgG, -IgA, and -IgM, respectively. The corresponding values in calf serum were 19.9, 30.6, 1.0, and 1.9 mg/mL. Apart from the general environmental effect (farm-year combination and laboratory conditions), the characteristics of the dams tested did not reveal any influence on colostrum immunoglobulin concentrations. Calving difficulty, as well as the birth weight and sex of calves, were found to be associated with serum concentrations in some cases. Heritability estimates were low to moderate, with the highest being for RID-IgG₁ in colostrum (h² = 0.28, standard error = 0.14) and serum (h² = 0.36, standard error = 0.18). Phenotypic correlations among the different immunoglobulins were generally positive or null, and none of the genetic correlations were significant due to large standard errors. The phenotypic correlation between dam colostrum and calf serum values was 0.2 for RID-IgG₁ and null for the 3 ELISA measurements. The correlation between RID-IgG₁ and ELISA-IgG was, unexpectedly, null for colostrum and 0.4 for serum. Increased RID-IgG₁ levels in calf serum were associated with improved survival, as well as better early growth and fewer health problems. These results thus showed that despite generally higher concentrations in beef than in dairy cattle, passive transfer was unsuccessful in a considerable number of calves. This should be brought to the attention of breeders to avoid negative effects on survival and subsequent performance. The heritability estimates were encouraging; however, obtaining phenotypes on a large scale constitutes a real limitation regarding these traits.

Do newborn puppies have their own microbiota at birth? Influence of type of birth on newborn puppy microbiota

With recent research in humans, a hypothesis known as the sterile womb paradigm has been challenged. The objectives of this study were to determine the presence of placental and fetal microbiomes in dogs, the effect of different types of parturition on the fetal microbiome, and the effect that the fetal microbiome has on early puppy development. A total of 96 newborn puppies from 17 dams were included in the study. Puppies were divided into two groups depending on the type of parturition (vaginal birth (VB) or cesarean section (CS)). Immediately after birth, swabs of the placenta and meconium were taken. Swabs of the oral and vaginal mucosa of the dam were taken in the second half of the pregnancy and just before parturition. All samples were analyzed with a classical bacteriological examination, and bacterial colonies were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The weight gain of each puppy was tracked daily in the first 7 days postpartum. Bacteria from several different genera were isolated from 86.5% of meconium samples and 57% of placenta samples. While the meconium microbiota resembled bacteria from the maternal vagina in VB puppies, the meconium microbiota of puppies born by CS indicated a relative resemblance to maternal oral and vaginal microbiota. A statistically significant difference in the relative growth rate between puppies born by VB and CS was found (p < 0.05), with puppies born by VB gaining weight faster compared to the CS group. This difference was even more noticeable when VB puppies were compared to puppies born by elective CS. Puppies born without a detectable meconium or placental microbiota showed a slower growth rate than those with a meconium microbiota, regardless of the type of parturition (p < 0.05). The findings of this study provide new information about the placental microbiome in healthy pregnant dams and suggest intrauterine colonization of the fetus in dogs. It seems that the type of delivery and bacterial colonization might be an important consideration for the weight gain in puppies in the first few days of life.

Immune differences in captive and free-ranging zebras (Equus zebra and E. quagga)

Wild mammals in ex situ captivity experience substantially different environmental conditions compared to free-ranging conspecifics, e.g., in terms of diet, climatic conditions, social factors, movement space, and direct anthropogenic disturbance. Moreover, animals in captivity frequently undergo management interventions such as medical treatments which may influence pathogen pressure. Captivity is known to affect immunological responses in some terrestrial and marine mammals; however, it is unclear whether this can be generalized to other taxa. Furthermore, little is known about how energetically costly life history stages such as lactation influence the immune system in wildlife. We measured expression of components of the constitutive and induced innate immunity and of the adaptive immune system in plains and mountain zebras (Equus quagga and E. zebra), including lactating and non-lactating individuals. As a proxy for general immune function, we screened for lytic equine herpesvirus (EHV) infection, a common and often latent pathogen which is reactivated in response to stress and immune challenge. Both energetically cheap markers of the constitutive innate immunity were lower in captive than in wild zebras, whereas energetically costly markers of the induced innate immunity were more highly expressed in captive zebras. Lactation was associated with higher titers of natural antibodies and lysozyme. Lytic EHV infection was not significantly correlated with any of the measured immune markers. Our results suggest that captivity and lactation may influence immune functions in zebra mares.

Serological and molecular investigation of hepatitis E virus in pigs reservoirs from Cameroon reveals elevated seroprevalence and presence of genotype 3

Background

Hepatitis E virus (HEV) is a zoonotic pathogen of which pigs have been established as reservoirs. In the present study, we investigated the presence of HEV among pigs in the Center and Littoral regions of Cameroon and performed the molecular characterization of positive strains.

Methodology

A total of 453 serum and stool samples were randomly collected from pigs in slaughterhouses in Obala, Douala and Yaounde. All samples were examined for the presence of anti-HEV IgG and IgM antibodies using ELISA assays. IgM positive stool samples were tested for HEV RNA using an RT-PCR assay, followed by a nested PCR assay for sequencing and phylogenetic analysis.

Results

Overall, 216 samples (47.7%, 95% CI: 43.1%-52.3%) were positive for at least one of the serological markers of HEV infection. Amongst these, 21.0% were positives for anti-HEV IgM, 17.7% for anti-HEV IgG, and 9.1% for both. A total of eight stool samples (5.9%) were positive for HEV RNA by nested RT-PCR. Phylogenetic analysis showed that the retrieved sequences clustered within HEV genotype 3.

Conclusion

This study shows a high prevalence of anti-HEV antibodies and the circulation of genotype 3 in the swine population in Cameroon. Subsequent studies will be needed to elucidate the zoonotic transmission of HEV from pigs to humans in Cameroon.

A review of diagnostic tests for diagnosing failure of transfer of passive immunity in dairy calves in New Zealand

The aim of this review is to critically assess the test characteristics and practicality of published data on direct and indirect tests for diagnosing failure of transfer of passive immunity (FPT) in dairy calves in New Zealand, to provide recommendations for veterinary practitioners, and to examine the recommended sample size for assessing herd-level prevalence of FPT and the confidence in the results obtained. The definition of FPT is based on measurement of concentrations of IgG in serum of neonatal calves after colostrum intake. The gold standard method for measurement of concentrations of IgG is radial immunodiffusion. However its cost, requirements for laboratory equipment, and the time taken to obtain results have meant that alternative tests have been developed. The turbidimetric immunoassay and ELISA also directly measure concentrations of IgG. Indirect tests include measurement of concentrations of total proteins (TP) in the laboratory or using a refractometer, γ-glutamyl transferase (GGT) activity, and the zinc sulfate turbidity (ZST) test. Of the indirect tests, measurement of concentrations of TP in the laboratory or using a refractometer combine high specificity and sensitivity with a consistent association with concentrations of IgG in calves between 1-7 days of age. Using a refractometer is less accurate than direct measurement in a laboratory, but is still a suitable test if low cost and speed are important. Although GGT activity is strongly associated with concentrations of IgG in serum, the relationship varies with time after birth. Therefore the target thresholds change with time, increasing error compared to the measurement of concentrations of TP in serum. Similarly, factors other than total concentrations of IgG have a significant effect on the association with ZST test, complicating interpretation. Thus, when direct measurement of concentrations of IgG is not feasible, the recommendation is that concentrations of TP in serum should be used as the diagnostic test for diagnosis of FPT, providing calves are not dehydrated. Using a sample size of 12 calves is suitable for estimating whether the herd-level prevalence of FPT is <20% or >20%, if there are no calves or >5 calves diagnosed with FPT, respectively, but is limited in diagnostic confidence when 1-4 calves test positive. Diagnostic interpretation can be significantly improved if tests of FPT are used alongside information on the likely risk of FPT on the tested farm.

The Repertoire of Human Antiglycan Antibodies and Its Dynamics in the First Year of Life

The repertoire of antiglycan antibodies of peripheral blood was studied using a microarray containing 487 glycan antigens: fragments of mammalian glycans (N- and O-chains of glycoproteins, as well as glycolipids) and also bacterial polysaccharides. The sera samples correspond to the third, sixth, and twelfth months of life. The infants were divided into four groups according to their nutrition type: breast milk, standard formula, and partially or extensively hydrolyzed formula. During the first year of life, the total amount of IgG decreased; presumably, the lifetime of maternal IgG in the newborns' bloodstream is much greater than is generally assumed. At the same time, the IgM content was low during the first six months and increased significantly by the twelfth month. The antiglycan IgM repertoire of one-year-old infants was still different from that of their mothers, as well as from the repertoire of unrelated donors, in particular, by the absence of antibodies against the Galβ1-3GlcNAc (Le^C) disaccharide, which is found in almost all healthy humans. It is noteworthy that the level of IgM of breast-fed infants was significantly lower than that of formula-fed by the twelfth month.

A Preterm Rat Model for Immunonutritional Studies

Neonates are born with an immature immune system, which develops during the first stages of life. This early immaturity is more acute in preterm newborns. The aim of the present study was to set up a preterm rat model, in which representative biomarkers of innate and adaptive immunity maturation that could be promoted by certain dietary interventions are established. Throughout the study, the body weight was registered. To evaluate the functionality of the intestinal epithelial barrier, in vivo permeability to dextrans was measured and a histomorphometric study was performed. Furthermore, the blood cell count, phagocytic activity of blood leukocytes and plasmatic immunoglobulins (Ig) were determined. Preterm rats showed lower erythrocyte and platelet concentration but a higher count of leukocytes than the term rats. Although there were no changes in the granulocytes’ ability to phagocytize, preterm monocytes had lower phagocytic activity. Moreover, lower plasma IgG and IgM concentrations were detected in preterm rats compared to full-term rats, without affecting IgA. Finally, the intestinal study revealed lower permeability in preterm rats and reduced goblet cell size. Here, we characterized a premature rat model, with differential immune system biomarkers, as a useful tool for immunonutritional studies aimed at boosting the development of the immune system.

Effect of butyrate on passive transfer of immunity in dairy calves

The objectives of this study were to determine the effects of supplemental butyrate on (1) Ig production in dams and (2) Ig absorption in their calves. Twenty dry dams fed a close-up total mixed ration were assigned to either a control treatment (CTRL-D) or a butyrate treatment where the close-up total mixed ration was supplemented with butyrate at 1% of dry matter intake (wt/wt; BUT-D). At calving, calves were assigned to 1 of 2 treatments: a control group fed colostrum replacer only (CTRL-C) and a butyrate group fed colostrum replacer with supplemental butyrate at 2.5% (wt/vol; BUT-C). Serum IgG, glucose, and β-hydroxybutyrate were measured weekly in both dams and calves. Additionally, calves were weighed weekly to determine average daily gain. In dams, serum IgG concentration was not different between CTRL-D and BUT-D (1,785 ± 117 vs. 1,736 ± 137 mg/dL, respectively), nor was there a change in Ig levels in the colostrum between control and butyrate groups. Serum total protein did not differ between CTRL-D and BUT-D dams. Dam dry matter intake did not differ between CTRL-D and BUT-D but did decrease 1 wk before parturition. Compared with CTRL-C calves, BUT-C calves had significantly decreased serum IgG concentration at 24 h (2,110 ± 124 vs. 1,400 ± 115 mg/dL), wk 1 (1,397 ± 121 vs. 866 ± 115 mg/dL), and wk 2 (1,310 ± 121 vs. 797 ± 115 mg/dL). Additionally, apparent efficiency of absorption was lower for the BUT-C group compared with the CTRL-C group (35.3 ± 2.1 vs. 25.9 ± 2.0). Differences in serum Ig concentrations between the CTRL-C and BUT-C groups did not affect average daily gain (0.59 ± 0.05 vs. 0.48 ± 0.05 kg/d, respectively), serum glucose concentrations, or serum β-hydroxybutyrate concentrations. These data demonstrate that butyrate inclusion in colostrum negatively affects IgG absorption in newborn calves, whereas calf body weight gains were unaffected.

Immunological Response of Pigs to Human Cells, Including Issues Such as the Production of Natural Antibodies in Newborns

Pigs have recently become very popular for use not only in xenotransplantation field, but in regeneration studies as well, sometimes with pigs being used as the scaffold. We have already presented our findings related to the pig immune system against human cells, including the complement systems, natural antibodies (NAs), and NK cells. In this study, we investigated the pig innate immunological reaction against human cells further. Our investigations included issues such as the production of NAs in newborns, day 0 and day 1, and sow colostrum. The alternative pathway for pig complement reacted with human cells, and pig NK cells and macrophages directly injured human aortic endothelial cells. Pig serum clearly contains the natural antibodies IgG and IgM to human peripheral blood mononuclear cells (PBMCs). Pig plasma from day 1 newborns contained almost the same levels of these natural antibodies to human PBMCs as those of sow plasma. On the other hand, pig plasma from day 0 newborns did not contain IgG and IgM to human PBMCs. In addition, sow colostrum clearly contained both IgG and IgM to human PBMCs. As expected, the pig innate immunity system reacted to human cells, including natural antibodies. However, the NAs of pigs, both IgM and IgG, against human cells do not exist in pig serum at day 0, but at day 1 and in mother's milk, indicating that NAs in newborns did not come from the placenta but from sow colostrum.

Using serum and plasma samples to assess failure of transfer of passive immunity in dairy calves

The objectives of this study were (1) to determine the differences in IgG and total protein (TP) content of serum and plasma samples collected from the same calves; (2) to evaluate the correlation between calf serum and plasma IgG levels, Brix scores, and TP concentrations; (3) to determine whether different cut-off values should be used for plasma and serum to assess failure of transfer of passive immunity (FTPI) in dairy calves; and (4) to evaluate the level of agreement between results obtained from using serum and plasma samples of the same calves to assess FTPI using optimal cut-off values. Blood samples (n = 217) were collected from Holstein calves at 3 to 10 d of age on 30 commercial dairy farms in Nova Scotia and Newfoundland, Canada. Paired serum and plasma samples were analyzed for IgG concentration by the reference radial immunodiffusion assay, transmission infrared (TIR) spectroscopy, digital and optical Brix refractometers, and optical TP refractometer. The IgG concentrations measured by RID and TIR spectroscopy in serum were similar to those in plasma. However, the Brix and TP refractometer readings were significantly higher in plasma than in serum. The prevalence of FTPI in serum and plasma samples based on a RID-IgG concentration <10 g/L was 43.3 and 46.5%, respectively. The RID-IgG concentration was correlated with TIR-IgG (r = 0.92 and 0.89), digital Brix (r = 0.80 and 0.80), optical Brix (r = 0.77 and 0.77), and optical TP (r = 0.75 and 0.77) refractometers in serum and plasma, respectively. The correlations between paired serum and plasma IgG content were 0.85 by TIR spectroscopy, 0.80 by digital Brix, 0.77 by optical Brix, and 0.79 by optical TP refractometer. The optimal cut-off values for TIR spectroscopy, digital Brix, optical Brix, and TP refractometers to assess FTPI using serum were 13.1 g/L, 8.7% Brix, 8.4% Brix and 5.1 g/dL, respectively; and the optimal cut-off values with plasma were 13.4 g/L, 9.4% Brix, 9.3% Brix and 5.8 g/dL, respectively. When using these optimal cut-off values, the level of agreement (88.1%) between results derived from testing serum and plasma by TIR spectroscopy was substantial, with a kappa (κ) value of 0.76. The results derived from testing serum and plasma by digital Brix refractometer showed substantial agreement (83.4%), with a κ value of 0.65, which is higher than the agreement and κ value (74.7% and 0.51) reported for the optical Brix refractometer. Substantial agreement (81.6%) between serum and plasma TP was also obtained when using the optical TP refractometer, with a κ value of 0.63. In conclusion, serum or plasma samples can be used interchangeably for measuring IgG concentrations and assessing FTPI in dairy calves. However, different cut-offs must be used to assess FTPI depending on the sample matrix. Furthermore, results obtained from serum samples showed higher agreement with the reference RID assay than those obtained from plasma samples.

Differential susceptibility to tetracycline, oxytetracycline and doxycycline of the calf pathogens Mannheimia haemolytica and Pasteurella multocida in three growth media

For clinical isolates of bovine Mannheimia haemolytica and Pasteurella multocida, this study reports minimum inhibitory concentration (MIC) differences for tetracycline, oxytetracycline and doxycycline between cation-adjusted Mueller-Hinton broth (CAMHB), foetal bovine serum (FBS) and Roswell Park Memorial Institute (RPMI) medium. MICs were determined according to CLSI standards and additionally using five overlapping sets of twofold dilutions. Matrix effect: (a) free drug MICs and minimum bactericidal concentrations (MBC) for all drugs were significantly higher in FBS than in CAMHB for both pathogens (p < 0.001); (b) MICs and MBCs were higher for CAMHB and FBS compared to RPMI for P. multocida only. Net growth rate for P. multocida in CAMHB was significantly slower than in FBS and higher than in RPMI, correlating to MIC and MBC ranking. Drug effect: doxycycline MICs and MBCs were significantly lower (p < 0.001) in both CAMHB and FBS than tetracycline and oxytetracycline for both pathogens. Only for M. haemolytica were oxytetracycline MIC and MBC significantly lower than tetracycline, precluding the use of tetracycline to predict oxytetracycline susceptibility in this species. Determining potencies of tetracyclines in a physiological medium, such as FBS, is proposed, when the objective is correlation with pharmacokinetic data for dosage determination.

Genome wide transcriptome analysis provides bases on colonic mucosal immune system development affected by colostrum feeding strategies in neonatal calves

Background

Delivery of colostrum within the first several hours after birth is vital for establishing successful passive immunity in neonatal dairy calves. However, it is unclear whether a difference in colostrum feeding strategy can affect the development of the calf gastrointestinal tract. The aim of this study was to evaluate the effect of colostrum feeding time within the first 12 h after birth on the colonic mucosal immune system in neonatal calves using a genome wide transcriptome analysis.

Results

RNA sequencing-based transcriptome analysis of colon tissues collected from 27 male Holstein calves which were randomly assigned to one of three colostrum feeding strategies – (immediately after birth (TRT0); 6 h after birth (TRT6); 12 h after birth (TRT12)) – and euthanized at 51 h of age detected 15,935 ± 210, 15,332 ± 415, and 15,539 ± 440 expressed genes in the colon under three treatments, respectively. The core transcriptome of the colon included 12,678 genes, with enriched “cellular process” and “metabolic process” as the top two biological functions with 802 of them being immune function related genes. Principal component analysis of the colon transcriptomes did not display a clear separation by colostrum feeding strategy and differential abundance analyses showed no significant difference in the expression of immune related genes among the treatments. Additionally, a weighted gene co-expression network analysis identified 4 significant (|correlation| > 0.50 and p ≤ 0.05) gene modules consisting of 122 immune related genes, which were positively or negatively correlated with the abundance of Lactobacillus and Faecalibacterium prausnitzii in the colon.

Conclusion

Transcriptome analysis indicates that the development of the colonic mucosal immune system in neonatal calves may be independent of the timing of initial colostrum meal within 12 h after birth. Our results also provide a molecular understanding of colonic biological function in neonatal calves and extends knowledge on how host gene expression profiles are associated with the abundance of specific bacterial groups in the colon.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5017-y) contains supplementary material, which is available to authorized users.

Effect of sex and reproductive status on the immunity of the temperate bat Myotis daubentonii

Studies of immunity in bat species are rare. However, it is important to determine immunological variations to identify factors influencing the health status of these endangered mammals from an evolutionary, ecological, conservation, and public health point of view. Immunity is highly variable and can be influenced by both internal (e.g. hormone levels, energy demand) and external factors (e.g. pathogens, climate). As bats have some peculiar ecological, energetic, and putative immunological characteristics, they are outstanding study organisms for ecoimmunological studies. We tested if (i) female bats have a higher immunity than males similar to most other mammalian species and (ii) individuals differ according to their energy demand (e.g. reproductive status). To study these questions, we sampled female and male Myotis daubentonii with different reproductive states and estimated their bacterial killing activity, hemolysis/hemagglutination titer, immunoglobulin G (IgG) concentration, and total and differential white blood cell counts. These methods characterize the cellular and humoral branches of both the adaptive and the innate immune responses of these individuals. Reproductively active males had lower cellular immunity compared to non-reproductive individuals. Pregnant females had increased IgG concentrations while hemolysis was enhanced during lactation. No clear trade-off between immunity and reproduction was found; instead immunity of males and female bats seems to be modulated differently due to varying hormonal and energetic states. Our data suggest that both adaptive and innate immunity as well as individual differences (i.e. sex and reproductive state) need to be considered to get a comprehensive overall picture of immunity in wild mammals.

Development of a polyclonal anti-dugong immunoglobulin G (IgG) antibody with evaluation of total plasma IgG in a living dugong (Dugong dugon) population

Species-specific antibodies (Ab) for the measurement of immunoglobulins (Ig) are valuable tools for determining the humoral immune status of threatened and endangered wildlife species such as dugongs. However, no studies have reported antibody reagents against dugong immunoglobulin. The object of this study was to develop an Ab with specificity for dugong IgG and apply this tool to survey total IgG levels in plasma samples from a live wild population of dugongs in southern Queensland, Australia. Dugong IgG was isolated from plasma by protein A/G column chromatography and a polyclonal antiserum was successfully raised against the dugong IgG through immunization of mice. The anti-dugong antiserum was reactive with dugong serum but not immunoglobulin from other species such as rats and humans. When tested against a panel of dugong plasma samples, relative IgG levels from dugongs (n = 116) showed biologically relevant relationships with pregnancy status and a principal component of Body Mass Index (BMI)/globulin/fecal glucocorticosteroid (chronic stress) levels combined, which together accounted for 9.2% of the variation in total Ig levels. Together these data suggest that dugongs show variation in total IgG and that this correlates with some physiological parameters of dugong health.

Refinement of a colostrum-deprived pig model for infectious disease research

Well-defined pig models are useful to study the pathogenicity of newly recognized pathogens or strains in pigs and serve as animal models for some human diseases. The conventional pig model, where research pigs are sourced from commercial high-health production systems, is commonly used due to the easiness of getting pigs in a timely manner. However, freedom of the pig for the pathogen of interest is important at study start and serological assays to screen pigs for antibodies against newly identified pathogens or molecular assays detecting all possible circulating pathogen variants may not yet exist. Using colostrum-deprived (CD) pigs is a good alternative strategy to circumvent passively-acquired immunity against the pathogen of interest or exposure to pathogens shortly after birth. However, CD pigs are difficult to rear as they are highly susceptible to infections, and mortality rates in the first few days of life are often very high. Herein we report on refinement of a CD pig model with consistent survival rates of 90-100% of the piglets. •Step-by-step protocol to derive and rear CD piglets with higher expected survival rates.•Pig housing improvement minimizes the risk of disease transmission.•Infectious virus disease research pig model purpose.

Effects of Microbial Aerosol in Poultry House on Meat Ducks' Immune Function

The aim of this study was to evaluate effects of microbial aerosols on immune function of ducks and shed light on the establishment of microbial aerosol concentration standards for poultry. A total of 1800 1-d-old cherry valley ducks were randomly divided into five groups (A, B, C, D, and E) with 360 ducks in each. To obtain objective data, each group had three replications. Concentrations of airborne bacteria, fungi, endotoxin in different groups were created by controlling ventilation and bedding cleaning frequency. Group A was the control group and hygienic conditions deteriorated progressively from group B to E. A 6-stage Andersen impactor was used to detect the aerosol concentration of aerobes, gram-negative bacteria, fungi, and AGI-30 microbial air sampler detect the endotoxin, and Composite Gas Detector detect the noxious gas. In order to assess the immune function of meat ducks, immune indicators including H5 AIV antibody titer, IgG, IL-2, T-lymphocyte transformation rate, lysozyme and immune organ indexes were evaluated. Correlation coefficients were also calculated to evaluate the relationships among airborne bacteria, fungi, endotoxin, and immune indicators. The results showed that the concentration of airborne aerobe, gram-negative bacteria, fungi, endotoxin have a strong correlation to H5 AIV antibody titer, IgG, IL-2, T-lymphocyte transformation rate, lysozyme, and immune organ indexes, respectively. In addition, when the concentration of microbial aerosol reach the level of group D, serum IgG (6–8 weeks), lysozyme (4 week) were significantly higher than in group A (P < 0.05); serum IL-2 (7 and 8 weeks), T-lymphocyte transformation rate, lysozyme (7 and 8 weeks), spleen index (6 and 8 weeks), and bursa index (8 week) were significantly lower than in group A (P < 0.05 or P < 0.01). The results indicated that a high level of microbial aerosol adversely affected the immune level of meat ducks. The microbial aerosol values in group D provide a basis for recommending upper limit concentrations of microbial aerosols for healthy meat ducks.

The future of neonatal BCG

We hypothesise that neonatal BCG (Bacillus Calmette-Guérin) might be used to adapt to a new phase in the history of human births. Among most mammals, the placenta is not effective at transferring antibodies to the fetus: antibodies are transferred immediately after birth via the colostrum. Among humans (and other mammals with hemochorial placentas) the transplacental transfer of antibodies (namely IgG) is effective. In humans, foetal concentrations of IgG sub-classes approximate to maternal concentrations at 38weeks and continue to increase thereafter. These facts explain inter-species differences regarding the basic needs of neonates. Among most mammals, the early colostrum is, strictly speaking, vital. Among humans, the main questions are about the bacteriological environment in the birthing place and how familiar it is to the mother. Today, most human beings are born in unfamiliar bacteriological environments characterized by a low microbial diversity. The effects of clinical environments may be amplified by the use of antibiotics and birth by caesarean, i.e. by-passing the bacteriologically rich perineal zone. There is already an accumulation of data confirming that the maturation of a balanced Th1/Th2 immune response is affected by the mode of delivery. There is also an accumulation of epidemiological studies detecting risk factors in the perinatal period for health conditions such as type 1 diabetes (and other autoimmune diseases), atopy, autism and obesity. In such a context there are reasons to plan randomized controlled trials with long term follow-up of the effects of BCG given immediately after birth, as a modulator of Th-1/Th-2 responses. A follow-up period in the region of 6-10years would be long enough to evaluate the prevalence of several nosologically well defined diseases. These studies would be ethically acceptable, since BCG is the only infancy vaccine that has been evaluated through randomised controlled trials with long term follow-up. Furthermore, whatever the standard of living of the populations and the research protocols, concordant results suggest that BCG has positive non-specific long term effects on health. Meanwhile, some simple adaptive practices are possible, such as, after a caesarean section, wrapping the neonate in clothes recently worn by the mother and, occasionally, putting the neonate in the arms of a person who is cohabiting with the mother.

In Vitro Evolution of Bovine Foamy Virus Variants with Enhanced Cell-Free Virus Titers and Transmission

Virus transmission is essential for spreading viral infections and is a highly coordinated process which occurs by cell-free transmission or cell-cell contact. The transmission of Bovine Foamy Virus (BFV) is highly cell-associated, with undetectable cell-free transmission. However, BFV particle budding can be induced by overexpression of wild-type (wt) BFV Gag and Env or artificial retargeting of Gag to the plasma membrane via myristoylation membrane targeting signals, closely resembling observations in other foamy viruses. Thus, the particle release machinery of wt BFV appears to be an excellent model system to study viral adaption to cell-free transmission by in vitro selection and evolution. Using selection for BFV variants with high cell-free infectivity in bovine and non-bovine cells, infectivity dramatically increased from almost no infectious units to about 105-106 FFU (fluorescent focus forming units)/mL in both cell types. Importantly, the selected BFV variants with high titer (HT) cell-free infectivity could still transmit via cell-cell contacts and were neutralized by serum from naturally infected cows. These selected HT-BFV variants will shed light into virus transmission and potential routes of intervention in the spread of viral infections. It will also allow the improvement or development of new promising approaches for antiretroviral therapies.