Passive Immunization Research Articles

Assessing colostral and serum immunoglobulin G in alpacas using Brix refractometry and total serum protein

The adequate transfer of passive immunity is a critical factor in neonatal development and survivability. Although well documented in the dairy and equine industries, the recognition of inadequate immunoglobulin transfer on-farm and its impact on the ability of alpaca cria to thrive is largely unknown. Colostrum samples were collected from female alpaca within 24 h of parturition by the owners and whole blood collected from cria by the investigators between 1 and 7 days of age. Direct IgG concentration of milk and serum was determined using radial immunodiffusion assay (RID) and was indirectly estimated using optical and digital Brix refractometry for total solids and clinical refractometry for total serum protein. There was a strong correlation between optical and digital Brix refractometry, and colostral IgG concentration determined by RID. There was a moderate correlation between serum IgG concentration determined by RID and total serum protein in crias. Optical and digital Brix refractometry for colostral IgG estimation and total serum protein for serum IgG estimation are reliable, accurate and easy-to-use tools that can be used on-farm by trained, competent technicians to assess a failure of passive transfer in alpacas. A pilot study at one property only was performed, due to COVID-19 travel restriction interference. Further research is required to determine the reference intervals for these tools to be practical.

RSV Disease Threat and Innovative Prevention Methods in Health Protection: A Review

Respiratory syncytial virus (RSV) causes infections of the lower respiratory tract. A group particularly vulnerable to severe infection are young children under 2 years of age and the elderly. The infection can cause the entire spectrum of respiratory symptoms from upper respiratory tract infections to severe courses requiring assisted breathing. Until recently, the only form of protection against infection was passive immunization, i.e. administration of immunoglobulins. Chief among these are palivizumab and nirsevimab. In May u June 2023, the Food and Drug Administration (FDA) approved for use 2 vaccines against RSV are Arexvy and Abrysvo. In this study, we focus on presenting and describing the clinical evidence supporting the effectiveness of these immunization methods.

Population-based Influenza and Respiratory Syncytial Virus Hospitalizations and In-hospital Mortality Rates Among Mexican Children Less Than Five Years of Age.

Population-based information regarding the impact of respiratory syncytial virus (RSV) and influenza on hospital admissions and mortality is scant for many countries. Prospective testing of RSV and influenza virus was undertaken in patients <5 years old admitted to hospital with acute respiratory infection (ARI) between July, 2014 and June, 2015, and mortality rates for children living in 3 municipalities in the state of San Luis Potosí were calculated. During the 12-month study period, 790 children living in these municipalities were admitted with ARI. RSV was detected in 245 (31%) and influenza in 47 (5.9%). History of preterm birth was recorded for 112 children on admission. For children <5 years old, ARI-, RSV- and influenza-associated admission rates were 23.2, 7.2 and 1.4 (per 1000 population), respectively. The corresponding admission rates per 1000 infants <1 year old were 78, 25.2 and 4.4. Preterm infant admission rates were 2 times higher than those of term infants. Six children died; RSV was detected in 4 (66.6%) of the deceased, while no deaths were associated with influenza. ARI and RSV in-hospital mortality rates for children <5 years were 0.18 and 0.12 per 1000 population. ARI and RSV mortality rates in preterm infants were 7 and 14 times higher than in term infants, respectively. RSV was associated with both high admission and in-hospital mortality rates in children <5 years old. Specific interventions, such as active or passive immunization, to prevent RSV infections are required to reduce ARI-associated infant mortality.

Bovine Colostrum and Its Management in UK Dairy Herds

Abstract At birth, the calf has a naïve immune system and is reliant upon maternal antibodies until it begins to produce its own. Gut absorption of these antibodies may be facilitated by the consumption of colostrum soon after birth, a process described as the “transfer of passive immunity”. Additional components found within colostrum, such as maternal leucocytes, microRNAs, hormones and oligosaccharides also contribute to calf health and development. These compounds stimulate intestinal epithelial cell development and the establishment of a healthy gut microbiome, which may enhance antibody absorption, inhibit pathogens and modulate immune responses. Different methods of colostrum collection, storage, handling and feeding will influence how colostrum is consumed and absorbed, and an appreciation of these factors is essential. Information © The Author 2024

Charting a path forward: Promising outcomes of convalescent plasma therapy in the care of severely B-cell depleted patients with persistent COVID-19.

Patients with severe B-cell depletion related to hematological malignancies or B-cell targeted therapy suffer from impaired antibody responses to SARS-CoV-2 and are at risk for prolonged COVID-19. In this population, COVID-19 convalescent plasma (CCP) may provide passive immunity, enhance immune response, and promote virus neutralization. This study evaluated outcomes of B-cell depleted patients with persistent COVID-19 treated with CCP. This analysis included all consecutive severely B-cell depleted patients with persistent COVID-19, receiving CCP at Rambam between 01.2022-02.2023. Persistent COVID-19 was defined as the presence of symptoms for ≥14 days in patients with negative SARS-CoV-2 nucleocapsid antibody test results. Twenty patients met inclusion criteria, 17 of whom had hematological malignancies, two suffered from rheumatoid arthritis and one had both. Twelve patients received anti-CD-20 treatment, one - CAR-T cells and three underwent stem cell transplantation. The median duration of COVID-19 symptoms was 27.5 days (range 14-97); 12 patients had mild-to-moderate COVID-19 and 8 had severe infection. Sixteen patients required hospitalization. The majority of patients received other COVID-19 therapies before CCP. Within a median of two days (range 1-16) post-infusion, 19/20 patients clinically improved. No CCP-associated adverse events were documented. COVID-19 symptoms recurred in 3 of the improved patients. Two patients died from COVID-19 on days 1 and 90 following the first CCP infusion. In severely B-cell depleted patients with persistent COVID-19, CCP is safe and associated with rapid clinical improvement. This subset of immunocompromised patients could particularly benefit from CCP administration.

Efficacy evaluation of anti-DEC-IgY against antibiotic-resistant diarrhoeagenic Escherichia coli.

Introduction. The rise of multi-drug-resistant bacteria poses a global threat. In 2017, the World Health Organization identified 12 antibiotic-resistant 'priority pathogens', including Enterobacteriaceae, highlighting the menace of Gram-negative bacteria. Diarrhoeagenic Escherichia coli (DEC)-induced diarrhoea is particularly problematic for travellers and infants. In contrast to other antibiotic alternatives, passive immunotherapy is showing promise by providing immediate and precise protection. However, mammalian-sourced antibodies are costly, hindering large-scale production. Egg-laying chicken-derived IgY antibodies present a cost-effective, high-yield solution, revolutionizing antibody-based therapeutics compared to mammalian IgG.Hypothesis/Gap Statement. This study hypothesized that developing anti-DEC-IgY could combat DEC infections effectively.Aim. The primary aim was to develop anti-DEC-IgY and assess its potential in DEC-induced diarrhoeal management.Method. Chickens were immunized with DEC antigens to induce an immune response. IgY antibodies were extracted from immune eggs and purified using ion-exchange column chromatography. Anti-DEC-IgY's ability to inhibit DEC growth was evaluated through growth inhibition assays. Anti-DEC-IgY's capacity to prevent E. coli adhesion was assessed using mice intestinal mucosa. In vivo experiments measured pathogen colonization reduction and infection severity reduction. P values were calculated to confirm statistical significance.Result. The antibacterial efficacy of anti-DEC-IgY by growth inhibition assay demonstrated that 25 mg ml-1 of IgY could inhibit the DEC growth. The anti-adherence-property was tested using mice intestinal mucosa and found that anti-DEC-IgY could prevent the E. coli adhesion. In vivo results suggest that 12 mg ml-1 of IgY will reduce the pathogen colonization in intestine and reduce the severity of the infection. The P values between the experimental groups confirm the statistical significance of the findings.Conclusion. The study findings suggest that IgY-based passive immunotherapy could be a potential strategy for managing the risks associated with antibiotic-resistant bacterial infections. Additionally, this study paves the way for the development of IgY-related research and applications in India.

Assessment of BoAHV-1 Seronegative Latent Carrier by the Administration of Two Infectious Bovine Rhinotracheitis Live Marker Vaccines in Calves.

Seronegative latent carriers (SNLCs) are animals that carry the virus without detectable antibodies and pose a risk for disease transmission and diagnostic challenges, suggesting the importance of consideration of marker vaccines in managing them. Therefore, in this study, we evaluated two modified live infectious bovine rhinotracheitis (IBR) marker vaccines (single and double deletions) for their ability to generate SNLC calves. These vaccines were administered to four groups (n = 3 in each group) of three-month-old calves in the presence or absence of passive immunity. Three hundred days after the first vaccination and after confirming the IBR seronegativity of all animals, dexamethasone was administered intravenously for five consecutive days. Only animals immunized with the modified live IBR marker vaccine (single deletion) in the absence of passive immunity exhibited a more enduring immune response than those vaccinated in the presence of passive immunity. Moreover, the administration of a modified live IBR marker vaccine (double deletion) to calves with passive immunity generated SNLC. These findings underscore the potential of live IBR marker vaccine (double-deletions) to aid serological diagnostic tools and develop vaccination protocols in achieving the desired immune response, particularly in the context of latent carrier status, offering valuable insights into optimizing vaccination strategies for effective IBR control.

Approach to prevention of respiratory syncytial virus disease in infants by passive immunization.

To support family physicians in discussing respiratory syncytial virus (RSV) immunizations with patients. Information was obtained through a literature review on the burden of RSV disease in infants; observational studies; randomized controlled trials; evidence presented by review agencies; product monographs; and National Advisory Committee on Immunization statements. There are now 3 options available for preventing severe RSV disease in infants: the monoclonal antibody palivizumab, the long-acting monoclonal antibody nirsevimab, and the new RSVpreF vaccine administered during pregnancy. Only a small number of infants at high risk of severe RSV disease are eligible for palivizumab. Nirsevimab has received Health Canada authorization for all infants and RSVpreF has received authorization for all pregnant women and pregnant people. There are multiple considerations for the use of each product, including authorization; availability; timing of administration; health status and social determinants of health of the infant; efficacy and effectiveness; safety; patient preference; and cost. The National Advisory Committee on Immunization has recently issued guidance on the use of RSV immunization products for infants. Family doctors should be aware of the indications, relative benefits, and recommendations for the 3 RSV immunization products to have informed discussions with patients, taking into account the preferences and circumstances of the pregnant woman or pregnant person or of the parent and infant.

Effects of feeding pasteurized waste milk or saleable milk to calves on weight, health and fecal Escherichia coli antimicrobial resistance.

The aim of this study was to compare the effects of feeding pasteurized waste milk or saleable milk to calves on weight, health and emergence of antimicrobial resistance in Escherichia coli strains isolated from those calves. An experimental study under field conditions on a commercial pasture-based Argentinian dairy farm was carried out. Forty Holstein calves were assigned randomly to either pasteurized waste milk (PWM) or non-pasteurized saleable milk (SM). The antimicrobial agents (AM) used on the farm, both to treat or prevent diseases, were recorded. The passive immunity level, calf live weight, AM presence in milk, clinical examination of calves, and E. coli isolation and identification, were performed. A total of 258 E. coli strains were isolated from fecal samples (132 isolates from SM calves and 126 from PWM calves at six sampling times). All E. coli isolated were used to perform AM susceptibility tests (disc diffusion and agar dilution). No differences were observed between groups in health parameters, average daily gain or prevalence of resistant E. coli strains to any AM evaluated throughout the study. Peaks of trimethoprim, sulfamethoxazole and enrofloxacin minimum inhibitory concentration (MIC) were observed at 30 d in E. coli from both groups of calves, whilst additional peaks to tetracyclin and ampicillin were observed only in SM calves. All MIC apart from gentamicin decreased at 75 and 90 d of age (during the weaning period). Gentamicin MIC behaved differently, having no peaks and increasing at 90 d only in PWM group. In conclusion, we found no evidence that emergence of antibiotic resistance is related to the consumption of pasteurized waste milk.

Diversity in the HLA-I Recognition of HLA-F Monoclonal Antibodies: HLA-F or HLA-Ib Monospecific, HLA-E or HLA-G Bispecific Antibodies with or without HLA-Ia Reactivity.

Previous investigators have used various anti-HLA-F monoclonal antibodies (mAbs) to demonstrate that the tissue distribution of HLA-F is highly restricted. Notably, these mAbs differed in their immunodiagnostic capabilities. Specifically, mAbs Fpep1.1 and FG1 detected HLA-F intracellularly in B cells but not on the cell surface, whereas mAb 3D11 detected HLA-F on the cell surface. The presence of HLA-F on T cells was recognized by mAb FG1 but not by mAb Fpep1.1. mAb 3D11 detected HLA-F on the cell surface of activated B cells and on peripheral blood lymphocytes, but not on the normal cells. Importantly, mAb 3D11 revealed that HLA-F exists as a heavy chain (HC) monomer, rather than as an HC associated with B2m. Although these mAbs are believed to be specific to HLA-F, their monospecificity has not been formally established, which is critical for immunodiagnostic and therapeutic purposes. Previously, we investigated the diversity of HLA class I reactivities of anti-HLA-E mAbs using HLA-I coated multiplex bead assays on a Luminex platform. We reported that more than 80% of the HLA-E mAbs were cross-reactive with other HLA-I molecules, with exceptionally few truly HLA-E-monospecific mAbs. In the present investigation, we generated IgG mAbs against HCs of HLA-F in Balb/C mice and examined the cross-reactivity of anti-HLA-F mAbs with other HLA-I alleles using a multiplex bead assay on the Luminex platform. Beads coated with an array of HLA homo- and heterodimers of different HLA-Ia (HLA-A, HLA-B, and HLA-C) and Ib (HLA-E, HLA-F, and HLA-G) alleles were used to examine the binding of the anti-HLA-F mAbs. Only two mAbs were HLA-F monospecific, and five were HLA-Ib restricted. Several anti-HLA-F mAbs cross-reacted with HLA-E (n = 4), HLA-G (n = 3), HLA-Ia alleles (n = 9), HLA-G and HLA-Ia (n = 2), and HLA-Ib and HLA-Ia (n = 6). This monospecificity and polyreactivity were corroborated by the presence of HLA-F monospecific and HLA-I-shared sequences. This study emphasizes the need to monitor the mono-specificity of HLA-F for reliable immunodiagnostics and passive immunotherapy.

Effect of Bamlanivimab as Monotherapy or in Combination with Etesevimab or Sotrovimab on Persistently High Viral Load in Patients with Mild-to-Moderate COVID-19: A Randomized, Phase2 BLAZE-4 Trial.

Treatment with monoclonal antibodies provides rapid, passive immunity and may stop COVID-19 disease progression. The study evaluated the effect of bamlanivimab (BAM) or BAM + etesevimab (ETE)/sotrovimab compared to placebo on SARS-CoV-2 viral load in patients with COVID-19. The phase2, randomized, single-dose study included patients aged between ≥ 18 and < 65years, not hospitalized at the time of randomization, and had ≥ 1 mild or moderate COVID-19 symptoms. Study included arms1-6 (placebo, BAM 175mg + ETE 350mg, BAM 700mg + ETE 1400mg, BAM 2800mg + ETE 2800mg, BAM 700mg alone, and BAM 350mg + ETE 700mg, respectively), BAM 700mg + ETE 700mg unintentional dosing; and arms7 and 8 (BAM 700mg + sotrovimab 500mg and placebo, respectively). The primary endpoint was proportion of patients with SARS-CoV-2 log viral load > 5.27 on day7 (persistently high viral load [PHVL]) who received BAM or BAM + (ETE or sotrovimab). A total of 725 patients, mean age 39.6years (range 18-75years), 50.2% male were randomized and infused with study drug in arms1-6; and a total 202 patients, mean age 38years (range 18-63years), 53.5% female were randomized and infused with study drug in arms7 and 8. A significantly lower proportion of patients in arms2-6 and arm 7 experienced PHVL on day7 compared to placebo. On day7, patients in arms2, 3, and 6 consistently experienced significantly greater reduction in viral load than placebo. Significant improvement was observed in time to viral load clearance and time to symptom improvement by day29 in some arms compared to placebo. No new safety concerns were observed with drug combinations. The study demonstrated that a significantly lower proportion of patients with mild-to-moderate COVID-19 treated with BAM or BAM + (ETE or sotrovimab) experienced a PHVL at day7. ClinicalTrials.gov identifier, NCT04634409.

VEDOLIZUMAB DOES NOT ALTER IMMUNOGLOBULIN LEVELS IN BREASTMILK OF MOTHERS WITH IBD

Abstract Diarrheal diseases are a major cause of infant mortality worldwide. Breastfeeding helps prevent such diseases by passive transfer of maternal antibodies against gastrointestinal pathogens previously encountered by the mother. The antibody secreting cells (ASC) that populate the lactating mammary gland (LMG) are educated in gastrointestinal lymphoid tissues, thus they express integrin a4b7. To recruit these ASC, the LMG expresses MAdCAM-1 and CCL28. Vedolizumab (vedo) blocks a combinatorial epitope on integrin a4b7, interfering with lymphocyte recruitment to the gut. Given the shared homing determinants between the gut and LMG, we investigated whether vedo might interfere with ASC trafficking to the LMG, therefore decreasing immunoglobulin (Ig) levels in breast milk. We measured Ig levels by ELISA in cryopreserved breast milk from mothers enrolled in Mommy’s Milk biorepository at the University of California, San Diego without and with Ulcerative Colitis(UC) or Crohn’s Disease(CD) and lactating mothers with UC and CD treated with vedo for more than 18 months. Milk samples were collected between 1 month and 15.45 months after childbirth. The levels of secretory IgA (SIgA) in breast milk of mothers without IBD (n=45) was not different from those of mothers with CD not on vedo (n=15) (301 ± 147 ug/mL vs. 322 ± 207 ug/mL). However, milk SIgA from mothers with UC not on vedo (n=7) were lower than non-IBD controls (213 ± 149 ug/mL vs. 301 ± 147ug/mL, p&amp;lt;0.01). We then compared milk SIgA from patients with CD and UC treated with vedo (CD: n= 9; 256 ± 80ug/mL, UC: n=10; 283 ± 87 ug/mL) with those from non-IBD controls (n=45; 301 ± 147ug/mL) and found no differences. Similarly, SIgA levels were not different between CD with or without vedo (256 ± 80 ug/mL vs. 322 ± 207 ug/mL) and as compared with non-IBD controls SIgA in patients with UC with vedo were unexpectedly higher than UC without vedo (283 ±87 ug/mL vs 213 ± 149 ug/mL, p&amp;lt;0.05). The levels of secretory IgM (SIgM) in milk were not different between mothers with UC or CD treated with vedo compared with non-IBD controls (65 ± 34 ug/mL, 69 ± 32 ug/mL, and 56 ± 37 ug/mL, respectively). Similarly, no significant difference was seen between patients with UC or CD not treated with vedo compared with the non-IBD controls (58±26 ug/mL, and 46 ± 24 ug/mL respectively). We conclude that vedo does not reduce SIgA nor SIgM levels in lactating mothers with IBD. We speculate that the higher SIgA in patients with UC treated with vedo is due to the small sample size. Vedo does not interfere with passive immunity during the lactation period, thus ASC must be able to use another integrin to arrest on microvessels of the LMG during the final stages of pregnancy.

Climatic and calf-related risk factors associated with failure of transfer of passive immunity in Holstein calves in a hot environment.

This retrospective observational study aimed to assess the effect of temperature-humidity index (THI) at calving and in the last trimester of pregnancy and calve-related factors affecting passive transfer of maternal immunoglobulin using Brix refractometry in Holstein calves. Blood samples from 4411 Holstein calves from a single large dairy farm in spring 2022 were used. A subset of data containing 6318 calvings was used to determine the effect of climatic conditions on the occurrence of agammaglobulinemia. Risk factors predictive of failure of passive transfer (FPT) were calculated using multiple logistic models. Females were 1.4 times more likely not to have FPT (56%; Brix% > 8 equivalent to ≥ 10g/L IgG) than males (47.2%). Calves born as singles increased the likelihood of not presenting FPT (52.6%) than calves born as twins (42.9%). Calves from cows with no dystocic delivery had a lower risk for FPT (odds ratio = 2.3) than calves from cows with dystocia. Agammaglobulinemia was 1.5 and 1.8 times more likely to occur in calves with THI ≥ 80 and ≥ 82 in the last trimester of gestation and at calving, respectively, than in calves not experiencing heat stress. Agammaglobulinemia was twice as likely to occur in male than in female calves. Calves with birth weight ≥ 37kg and gestation length ≥ 275kg were less likely to present agammaglobulinemia than lighter calves and calves with shorter gestation periods. This study raises questions for management practices in Holstein calves undergoing in utero heat stress and around calving to avoid agammaglobulinemia.

Diarreia naturalmente adquirida em bezerros do nascimento aos 25 dias de idade: ocorrência, sinais clínicos e resposta ao tratamento

Diarrhea has a multifactorial etiology and is one of the main diseases affecting dairy calves, promoting high mortality rates in the first weeks of life. This study aimed to assess diarrhea incidence and clinical aspects, as well as clinical responses to treatment (oral and intravenous) with electrolyte solutions. A total of 40 crossbred newborn calves were subjected to daily physical examination until 25 days. Calves with diarrhea (score 3) and dehydration (8% to 10%) received electrolyte replacement therapy orally or intravenously, according to estimated fluid loss, as well as a maintenance volume (oral). Blood and urine samples were collected between 16 and 24 hours after birth and at 5, 10, 15, 20, and 25 days; in diarrheic animals, these materials were collected immediately after the identification of diarrhea and at 2, 12, 24, and 48 hours after treatment initiation. Globular Volume (GV) and Total Plasma Proteins (TPP) were evaluated, in addition to physicochemical urine characteristics. Failures in the transfer of passive immunity may have contributed to the occurrence of diarrhea in 30 calves (75%), which maintained good body condition with no complications. Urine analysis showed a higher pH in non-diarrheic calves (6.7) compared to diarrheic calves (6.2) (p=0.0029), indicating acidification; higher GV, TPP, and urine density were found for diarrheic calves, with reductions 2 hours after hydration and slight variations up to 48 hours, indicating the effectiveness of hydration and acidosis correction.

Intramammary administration of lipopolysaccharides at parturition enhances immunoglobulin concentration in goat colostrum

In newborn ruminants, transfer of passive immunity is essential to obtain protection against pathogens. This study aimed to increase the permeability of the blood-milk barrier using intramammary lipopolysaccharides (LPS) in goats at parturition to modulate colostrum composition. Twenty multiparous Majorera dairy goats were randomly allocated in one of the two experimental groups. The LPS group (n = 10) received an intramammary administration (IA) of saline (2 mL) containing 50 µg of LPS from Escherichia coli (O55:B5) in each half udder at parturition. The control group (n = 10) received an IA of saline (2 mL). Rectal temperature (RT) was recorded, and a blood sample was collected at parturition (before IA). In addition, RT was measured, and blood and colostrum/milk samples were collected on day (d) 0.125 (3 hours), 0.5 (12 hours), 1, 2, 4, 7, 15 and 30 relative to the IA. Goat plasma immunoglobulin G (IgG) and M (IgM) and serum β-hydroxybutyrate, glucose, calcium, free fatty acids, lactate dehydrogenase and total protein concentrations were determined. Colostrum and milk yields as well as chemical composition, somatic cell count (SCC), IgG and IgM concentrations were measured. The MIXED procedure (SAS 9.4) was used, and the model included the IA, time, and the interaction between both fixed effects. Statistical significance was set as P < 0.05. Goats from the LPS group showed higher RT on d 0.125, 0.5 and 4 relative to the IA compared to the control group (PIA×Time = 0.007). Goat serum biochemical variables and plasma IgG and IgM concentrations were not affected by the IA. Colostrum and milk yield as well as chemical composition were not affected by the IA, except for milk lactose percentage that was lower in the LPS group compared to the control group (4.3 ± 0.08 and 4.6 ± 0.08%, respectively PIA = 0.026). Colostrum SCC was higher in the LPS group than in the control group (3.5 ± 0.09 and 3.1 ± 0.09 cells × 106/mL, respectively; PIA = 0.011). Similarly, milk SCC increased in the LPS group compared to the control group (PIA = 0.004). The LPS group showed higher IgG (PIA = 0.044) and IgM (PIA = 0.037) concentrations on colostrum than the control group (31.9 ± 4.8 and 19.0 ± 4.8 mg/mL, 0.8 ± 0.08 and 0.5 ± 0.08 mg/mL, respectively). No differences in milk IgG and IgM concentrations between groups were observed. In conclusion, the IA of LPS at parturition increases RT, SCC and IgG and IgM concentrations in colostrum without affecting either yield or chemical composition.

PEDV-spike-protein-expressing mRNA vaccine protects piglets against PEDV challenge.

Porcine epidemic diarrhea virus (PEDV), a swine enteropathogenic coronavirus, causes severe diarrhea in neonatal piglets, which is associated with a high mortality rate. Thus, developing effective and safe vaccines remains a top priority for controlling PEDV infection. Here, we designed two lipid nanoparticle (LNP)-encapsulated mRNA (mRNA-LNP) vaccines encoding either the full-length PEDV spike (S) protein or a multiepitope chimeric spike (Sm) protein. We found that the S mRNA-LNP vaccine was superior to the Sm mRNA-LNP vaccine at inducing antibody and cellular immune responses in mice. Evaluation of the immunogenicity and efficacy of the S mRNA vaccine in piglets confirmed that it induced robust PEDV-specific humoral and cellular immune responses in vivo. Importantly, the S mRNA-LNP vaccine not only protected actively immunized piglets against PEDV but also equipped neonatal piglets with effective passive anti-PEDV immunity in the form of colostrum-derived antibodies after the immunization of sows. Our findings suggest that the PEDV-S mRNA-LNP vaccine is a promising candidate for combating PEDV infection.IMPORTANCEPorcine epidemic diarrhea virus (PEDV) continues to harm the global swine industry. It is important to develop a highly effective vaccine to control PEDV infection. Here, we report a PEDV spike (S) mRNA vaccine that primes a potent antibody response and antigen-specific T-cell responses in immunized piglets. Active and passive immunization can protect piglets against PED following the virus challenge. This study highlights the efficiency of the PEDV-S mRNA vaccine and represents a viable approach for developing an efficient PEDV vaccine.

Virus-like particle vaccine displaying an external, membrane adjacent MUC16 epitope elicits ovarian cancer-reactive antibodies

BackgroundMUC16 is a heavily glycosylated cell surface mucin cleaved in the tumor microenvironment to shed CA125. CA125 is a serum biomarker expressed by > 95% of non-mucinous advanced stage epithelial ovarian cancers. MUC16/CA125 contributes to the evasion of anti-tumor immunity, peritoneal spread and promotes carcinogenesis; consequently, it has been targeted with antibody-based passive and active immunotherapy. However, vaccination against this self-antigen likely requires breaking B cell tolerance and may trigger autoimmune disease. Display of self-antigens on virus-like particles (VLPs), including those produced with human papillomavirus (HPV) L1, can efficiently break B cell tolerance.ResultsA 20 aa juxta-membrane peptide of the murine MUC16 (mMUC16) or human MUC16 (hMUC16) ectodomain was displayed either via genetic insertion into an immunodominant loop of HPV16 L1-VLPs between residues 136/137, or by chemical coupling using malemide to cysteine sulfhydryl groups on their surface. Female mice were vaccinated intramuscularly three times with either DNA expressing L1-MUC16 fusions via electroporation, or with alum-formulated VLP chemically-coupled to MUC16 peptides. Both regimens were well tolerated, and elicited MUC16-specific serum IgG, although titers were higher in mice vaccinated with MUC16-coupled VLP on alum as compared to L1-MUC16 DNA vaccination. Antibody responses to mMUC16-targeted vaccination cross-reacted with hMUC16 peptide, and vice versa; both were reactive with the surface of CA125+ OVCAR3 cells, but not SKOV3 that lack detectable CA125 expression. Interestingly, vaccination of mice with mMUC16 peptide mixed with VLP and alum elicited mMUC16-specific IgG, implying VLPs provide robust T help and that coupling may not be required to break tolerance to this epitope.ConclusionVaccination with VLP displaying the 20 aa juxta-membrane MUC16 ectodomain, which includes the membrane proximal cleavage site, is likely to be well tolerated and induce IgG targeting ovarian cancer cells, even after CA125 is shed.

Veal calves management in Québec, Canada: Part I. Association between passive immunity transfer at arrival and health disorders

Morbidity and mortality remain important concerns for veal production which traditionally involves very young calves being transported directly from dairy farms to calf-raising facilities or sold through auction markets from dairy farms. There are few studies that examine the relationship between transfer of passive immunity and health outcomes in veal production in Québec. The objective of this study was to investigate the risk factors associated with morbidity and mortality in milk and grain-fed veal facilities in Québec. Between October 2017 and December 2018, a prospective cohort study was conducted on 59 batches of milk- and grain-fed veal calves from Montérégie and Centre du Québec regions in Québec, Canada. A total of 30 calves per batch were randomly sampled for the transfer of passive immunity (TPI) status using the Brix refractometer (serum threshold ≥ 8.4%). Throughout the production cycle, arrival, treatment, mortality, and slaughter records of each batch of calves were extracted and used to quantify individual- and group-level risk factors. Morbidity and mortality were modelled through generalized linear mixed models (GLMMs) using a logit link, as function of categorical variables (individual inadequate TPI, arrival season, purchasing sites, and arrival weights) and a continuous variable (proportion of inadequate TPI in the batch). Given that the health and performance data are usually collected retrospectively under commercial settings, incomplete data was recognized as a potential issue. Thus, multiple imputation models were used. From 59 batches where 1729 calves were sampled for measuring TPI, 1084 calves had a serum Brix% < 8.4% giving a prevalence of 62.7% of inadequate TPI. The prevalence of morbidity and mortality in those 59 batches were not associated with the batch-level inadequate TPI prevalence. On the other hand, individual calves with inadequate TPI had higher odds of morbidity (OR: 1.56; 95% CI: 1.2–2.05, P = 0.001) compared to those calves with adequate TPI. Odds of mortality, on the other hand, were not significantly affected by inadequate TPI (OR:1.27; 95% CI: 0.74–2.18, P = 0.3). Calves arriving to the facility during the winter season had lower odds of mortality than those arriving in fall (OR:0.16; 95% CI: 0.03–0.78, P = 0.02). In conclusion, this study suggests that inadequate TPI, as assessed upon arrival in veal farms, remains an important concern for negative health outcomes in veal calves.

Trivalent immunization with metal-binding proteins confers protection against enterococci in a mouse infection model.

Enterococcus faecalis is ranked among the top five bacterial pathogens responsible for catheter-associated urinary tract infections, wound infections, secondary root canal infections, and infective endocarditis. Previously, we showed that inactivation of either the manganese- and iron-binding (EfaA) or zinc-binding (AdcA and AdcAII) lipoproteins significantly reduced E. faecalis virulence. Here, we explored whether immunization using a multi-valent approach induces protective immunity against systemic enterococcal infections. We found that multi-antigen antisera raised against EfaA, AdcA, and AdcAII displayed similar capacities to initiate neutrophil-mediated opsonization, like their single-antigen counterparts. Further, these antigen-specific antibodies worked synergistically with calprotectin, a divalent host metal chelator, to inhibit the growth of E. faecalis in laboratory media as well as in human sera. Using the Galleria mellonella invertebrate model and mouse peritonitis model, we showed that passive immunization with multi-antigen antisera conferred robust protection against E. faecalis infection, while the protective effects of single antigen antisera were negligible in G. mellonella, and negligible-to-moderate in the mouse model. Lastly, active immunization with the 3-antigen (trivalent) cocktail significantly protected mice against either lethal or non-lethal E. faecalis infections, with this protection appearing to be far-reaching based on immunization results obtained with contemporary strains of E. faecalis and closely related Enterococcus faecium.

Humanized Antibodies. Modern Developments and Prospects for the Creation of Medical Protectors Against Biological Threads and Hazards

Passive immunization is the variant of the immunization, in which antibodies are introduced into the body in quantities, sufficient to provide a therapeutic effect. One of the «windows of opportunity» for passive immunization is an urgent post-exposure prophylaxis of infectious diseases and their preventive therapy, especially in the absence of chemotherapy drugs suitable for these purposes or their insufficient effectiveness. The existing heterologous drugs based on hyperimmune sera are highly reactogenic, and obtaining donor human immunoglobulins is associated with a number of ethical and technical restrictions. Therefore, biotechnologies that make it possible to obtain, on an industrial scale, low-reactogenic preparations of chimeric monoclonal antibodies with partially human specificity, as well as recombinant antibodies with fully human specificity, have enormous prospects. This trend is called «humanization of antibodies.» The purpose of this article is to analyze modern developments and to show the prospects for creating humanized antibodies specific to antigens of pathogens of especially dangerous infections and toxins as medical biological protection agents. The sources of the research are English-language studies and the scientific literature available via the Internet. The research method is an analysis of scientific sources on the topic being studied from the general to the specific. Results and discussion. The history of the creation of specific prevention drugs based on heterologous and homologous sera/immunoglobulins and monoclonal antibodies is presented. It has been shown in the article, that humanized specific monoclonal antibodies are widely used currently for the treatment of a number of severe chronic diseases (for example, rheumatoid arthritis, psoriasis, immunoinflammatory bowel diseases, malignant tumors). Conclusion. Recently, there has been an increase in numbers of both scientific research and developments, and drugs of recombinant antibodies already approved for use in clinical practice, specific to antigens of pathogens of especially dangerous infections and toxins - potential agents of bioterrorism, such as the anthrax microbe, botulinum toxins of various types, plant toxins ricin and abrin, ebolaviruses, coronaviruses. Such drugs can also be used as medical protectors against biological threats and hazards.