Determination of colostrum quality using Brix refractometer in sheep.

In this study, we aimed to determine the quality of colostrum in sheep by using Brix refractometer. The research included 100 sheep of Merino X Kivircik crossbred. From each, we collected 15 mL of colostrum samples in falcon tubes within the first 8 h after delivery. Mean colostral IgG level of sheep was 156.68 ± 7.23 g L-1, optical and digital Brix refractometer values (%) were determined as 27.43 ± 0.53 and 27.69 ± 0.60, respectively. Ewes carrying twin lambs produced significantly higher quality colostrum than those carrying single lambs. However, parity did not affect the colostrum quality. Optical and digital Brix values were correlated with gold standard radial immunodiffusion (RID) colostral IgG level (r = 0.70 and r = 0.64, respectively). Also, optical and digital Brix refractometers were found to be highly correlated (r = 0.98, P < 0.001). While the optimal Brix value was 22% for the 50, 60 and 70 g L-1 IgG threshold values (by means of RID as the potential good quality threshold value for ewe colostrum quality), this value was 23% for 80 g L-1. We can conclude that Brix refractometers is a valuable tool for determining ewe colostrum quality. A cut point of 22% Brix for defining good quality colostrum in ewes was most appropriate for our data.

Changes in the N-glycosylation of porcine immune globulin G during postnatal development.

N-glycosylation influences the effectiveness of immune globulin G (IgG) and thus the immunological downstream responses of immune cells. This impact arises from the presence of N-glycans within the Fc region, which not only alters the conformation of IgG but also influences its steric hindrance. Consequently, these modifications affect the interaction between IgG and its binding partners within the immune system. Moreover, this posttranslational modification vary according to the physiological condition of each individual. In this study, we examined the N-glycosylation of IgG in pigs from birth to five months of age. Our analysis identified a total of 48 distinct N-glycan structures. Remarkably, we observed defined changes in the composition of these N-glycans during postnatal development. The presence of agalactosylated and sialylated structures increases in relation to the number of N-glycans terminated by galactose residues during the first months of life. This shift may indicate a transition from passively transferred antibodies from the colostrum of the sow to the active production of endogenous IgG by the pig's own immune system.

Touchpad-based immunochromatographic strip for detecting the skin surface proteins.

This study demonstrates, for the first time, the proof-of-concept of a novel immunosensor, a touchpad-based immunochromatographic strip, that non-invasively extracts and detects skin surface proteins. The strip was composed of a nitrocellulose membrane at the center, where a spot of anti-human IgG capture antibody was physically adsorbed. The capture antibody spot was covered with a glass fiber membrane impregnated with phosphate-buffered saline (PBS) to extract skin surface proteins, avoiding direct contact of the human skin with the capture antibodies. Skin surface IgG was detected in two steps: (1) touching the capture antibody via a glass fiber membrane containing PBS, and (2) dipping the strip into the Au-nanoparticle-labeled secondary antibody to visualize the existence of the captured skin surface IgG on the strip. We qualitatively demonstrated that using a very small amount of PBS while maintaining contact with the skin, skin surface proteins can be concentrated and detected, even with a relatively low-sensitivity immunochromatographic chip. This sensor is expected to be a potential biosensor for the non-invasive diagnosis of the integrity of human skin.

Salivary immunoglobulin levels and periodontal indices in Brazilian children with and without type 1 diabetes.

This cross-sectional study evaluated the association between salivary immunoglobulins, plaque index, and gingival index in Brazilian children with and without type 1 diabetes mellitus (DM1). The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for the reporting of observational studies was followed. The DM1 group had 38 children, and an equal number of volunteers matched by sex and age were recruited as controls. Clinical examination was performed for plaque index and gingival index determination. Non-stimulated whole saliva was collected. Concentrations of IgA, IgG, and IgM were determined by ELISA test. Data were tested by the Kolmogorov-Smirnov, Mann-Whitney, and Spearman tests and a multiple linear regression model (p<0.05) was performed. Gingival index was higher in the Control (DM1: 0.16±0.17; Control: 0.24±0.23, p=0.040). In DM1, there was a correlation between IgA and age (rho=0.371, p=0.024), IgM and IgG (rho=0.459, p=0.007), and IgM and gingival index (rho=0.394, p=0.014). In DM1, multiple linear regression showed that age (p=0.041; ß=0.363), gingival index (p=0.041; ß=0.398), and plaque index (p=0.008; ß=-0.506) were good predictors of IgA levels in saliva. Thus, IgA was the only researched immunoglobulin that was directly associated with plaque and gingival indices in Brazilian children with DM1, but not in control subjects.

An Unconventional Immunosensor for Biomolecule Detection via Nonspecific Gold Nanoparticle-Antibody Interactions.

Immunogold, that is, gold nanoparticles (AuNPs) conjugated with biomolecules such as antibodies and peptides, have been widely used to construct sandwiched immunosensors for biodetection. Two main challenges in these immunoassays are difficulties in finding and validating a suitable antibody, and the nonspecific interaction between the substrate and immunogold, which lowers the detection sensitivity and even causes false results. To avoid these issues, we took advantage of the nonspecific interaction between AuNPs and capture antibodies and proposed a new sensing mechanism. That is, after the capture of analyte targets by the capture antibodies on the substrate, AuNPs of certain chemical functionality would preferably bind to the free capture antibodies. Consequently, the amount of deposited AuNPs will inversely depend on the concentration of the analytes. As a proof-of-concept, we designed a mass-based sensor where anti-IgG antibodies were coated on a quartz crystal microbalance substrate. After IgG was introduced, tannic acid-capped AuNPs were applied to bind with the free anti-IgG antibody molecules. A frequency change (Δf) of the quartz substrate was induced by the increased mass loading. To further amplify the loading mass, an Ag enhancer solution was added, and Ag growth was catalyzed by the bound AuNPs. The Δf response showed a concentration-dependent decrease when increasing IgG concentration with a detection limit of 2.6 ng/mL. This method relies on the nonspecific interaction between AuNPs and anti-IgG antibodies to realize sensitive detection of IgG and eliminates the use of detection antibodies. The concept is an alternative to many existing immunoassay technologies.

Protein-Centric Analysis of Personalized Antibody Repertoires Using LC-MS-Based Fab-Profiling on a timsTOF.

Endogenous antibodies, or immunoglobulins (Igs), abundantly present in body fluids, represent some of the most challenging samples to analyze, largely due to the immense variability in their sequences and concentrations. It has been estimated that our body can produce billions of different Ig proteins with different isotypes, making their individual analysis seemingly impossible. However, recent advances in protein-centric proteomics using LC-MS coupled to Orbitrap mass analyzers to profile intact Fab fragments formed by selective cleavage at the IgG-hinge revealed that IgG repertoires may be less diverse, albeit unique for each donor. Serum repertoires seem to be dominated by a few hundred clones that cumulatively make up 50-95% of the total IgG content. Enabling such analyses required careful optimization of the chromatography and mass analysis, as all Fab analytes are highly alike in mass (46-51 kDa) and sequence. To extend the opportunities of this mass-spectrometry-based profiling of antibody repertoires, we here report the optimization and evaluation of an alternative MS platform, namely, the timsTOF, for antibody repertoire profiling. The timsTOF mass analyzer has gained traction in recent years for peptide-centric proteomics and found wide applicability in plasma proteomics, affinity proteomics, and HLA peptidomics, to name a few. However, for protein-centric analysis, this platform has been less explored. Here, we demonstrate that the timsTOF platform can be adapted to perform protein-centric LC-MS-based profiling of antibody repertoires. In a side-by-side comparison of the timsTOF and the Orbitrap we demonstrate that the extracted serum antibody repertoires are alike qualitatively and quantitatively, whereby in particular the sensitivity of the timsTOF platform excels. Future incorporation of advanced top-down capabilities on the timsTOF may make this platform a very valuable alternative for protein-centric proteomics and top-down proteomics and thus also for personalized antibody repertoire profiling.

Diagnosis of human brucellosis: Systematic review and meta-analysis.

BACKGROUND: Brucellosis, a widely spread zoonotic disease, poses significant diagnostic challenges due to its non-specific symptoms and underreporting. Timely and accurate diagnosis is crucial for effective patient management and public health control. However, a comprehensive comparative review of available diagnostic tests is lacking. METHODOLOGY/PRINCIPAL FINDINGS: This systematic review addressed the following question: 'What is the accuracy of the available tests to confirm human brucellosis?' Two independent reviewers examined articles published up to January 2023. The review included original studies reporting symptomatic patients with brucellosis suspicion, through any index test, with sensitivity and/or specificity as outcomes. As exclusion criteria were considered: sample size smaller than 10 patients, studies focusing on complicated brucellosis, and those lacking essential information about index or comparator tests. Sensitivity and specificity were assessed, with consideration for the index test, and 'culture' and 'culture and standard tube agglutination test (SAT)' were used as reference standards. Bias assessment and certainty of evidence were carried out using the QUADAS-2 and GRADE tools, respectively. A total of 38 studies reporting diagnostic test performance for human brucellosis were included. However, the evidence available is limited, and significant variability was observed among studies. Regarding the reference test, culture and/or SAT are deemed more appropriate than culture alone. Rose Bengal, IgG/IgM ELISA, and PCR exhibited equally high performances, indicating superior overall diagnostic accuracy, with very low certainty of the evidence. CONCLUSIONS/SIGNIFICANCE: This systematic review underscores the potential of the Rose Bengal test, IgG/IgM ELISA, and PCR as promising diagnostic tools for brucellosis. However, the successful implementation and recommendations for their use should consider the local context and available resources. The findings highlight the pressing need for standardization, improved reporting, and ongoing advancements in test development to enhance the accuracy and accessibility of brucellosis diagnosis.

The ability of a handheld near-infrared spectrometer to do a rapid quality assessment of bovine colostrum, including the immunoglobulin G concentration.

Portable infrared-based instruments have made important contributions in different research fields. Within the dairy supply chain, for example, most of portable devices are based on near-infrared spectroscopy (NIRS) and are nowadays an important support for farmers and operators of the dairy sector, allowing fast and real-time decision-making, particularly for feed and milk quality evaluation and animal health and welfare monitoring. The affordability, portability, and ease of use of these instruments have been pivotal factors for their implementation on farm. In fact, pocket-sized devices enable nonexpert users to perform quick, low-cost, and nondestructive analysis on various matrixes without complex preparation. Because bovine colostrum (BC) quality is mostly given by the IgG level, evaluating the ability of portable NIRS tools to measure antibody concentration is advisable. In this study we used the wireless device SCiO manufactured by Consumer Physics Inc. (Tel Aviv, Israel) to collect BC spectra and then attempt to predict IgG concentration and gross and fine composition in individual samples collected immediately after calving (<6 h) in primiparous and pluriparous Holstein cows on 9 Italian farms. Chemometric analyses revealed that SCiO has promising predictive performance for colostral IgG concentration, total Ig concentration, fat, and AA. The coefficient of determination of cross-validation (R2CV) was in fact ≥0.75). Excellent accuracy was observed for dry matter, protein, and S prediction in cross-validation and good prediction ability in external validation (R2CV ≥ 0.93; the coefficient of determination of external validation, R2V, was ≥0.82). Nonetheless, SCiO's ability to discriminate between good- and low-quality samples (IgG ≥ vs. < 50 g/L) was satisfactory. The affordable cost, the accurate predictions, and the user-friendly design, coupled with the increased interest in BC within the dairy sector, may boost the collection of extensive BC data for management and genetic purposes in the near future.

Concentrations of antimicrobial components in milk at dry off and postpartum and their relationships to new high somatic cell counts at quarter level in dairy cows.

We investigated the antimicrobial components in cow milk at dry off and postpartum and their contribution in preventing new high SCC at quarter level. Milk samples from 72 quarters of 19 lactating cows were collected at last milking before dry off and at 7 d after parturition. Milk yield of each cow was recorded and SCC, IgG, IgA, lactoferrin, lingual antimicrobial peptide (LAP), and S100A7 concentrations in each quarter milk sample were measured. The postpartum milk yield was significantly higher than that at dry off. The IgG, IgA and lactoferrin concentrations in milk at dry off were significantly higher than those at postpartum, whereas the LAP concentration was lower. Quarters with SCC < 300 000 cells/ml at both dry off and postpartum were classified as persistent low SCC (PL) whereas those that rose above that same threshold postpartum were classified as new high SCC (NH). At dry off, IgG and LAP concentrations in milk were significantly higher in PL than in NH. These results suggest that high LAP concentrations during the dry period may contribute toward the prevention of new high SCC.

High-Throughput Glycan Profiling of Human Serum IgG Subclasses Using Parallel Reaction Monitoring Peptide Bond Fragmentation of Glycopeptides and Microflow LC-MS.

LC-MS-based N-glycosylation profiling in four human serum IgG subclasses (IgG1, IgG2, IgG3, and IgG4) often requires additional affinity-based enrichment of specific IgG subclasses, owing to the high amino acid sequence similarity of Fc glycopeptides among subclasses. Notably, for IgG4 and the major allotype of IgG3, the glycopeptide precursors share identical retention time and mass and therefore cannot be distinguished based on precursor or glycan fragmentation. Here, we developed a parallel reaction monitoring (PRM)-based method for quantifying Fc glycopeptides through combined transitions generated from both glycosidic and peptide bond fragmentation. The latter enables the subpopulation of IgG3 and IgG4 to be directly distinguished according to mass differences without requiring further enrichment of specific IgG subclasses. In addition, a multinozzle electrospray emitter coupled to a capillary flow liquid chromatograph was used to increase the robustness and detection sensitivity of the method for low-yield peptide backbone fragment ions. The gradient was optimized to decrease the overall run time and make the method compatible with high-throughput analysis. We demonstrated that this method can be used to effectively monitor the relative levels of 13 representative glycoforms, with a good limit of detection for individual IgG subclasses.

Characterization of lyophilized equine colostrum.

Foals require maternal colostrum in the first hours of life to prevent failure of transfer of passive immunity (FTIP). Innovative storage methods such as lyophilization may enable conservation of colostrum immunoglobulins by a differentiated process of dehydration. The current study aimed to compare the quality of equine colostrum after freezing and after the lyophilization process. Thirty-one pregnant Quarter Horse mares were used. The IgG concentration of frozen and lyophilized colostrum was determined by simple radial immunodiffusion (SRID) and Brix refractometry. The physical-chemical composition (pH, total protein (TP), fat, lactose, salts, total solids (TS), and density) of the samples was evaluated and the lyophilized colostrum reconstitution test was performed. There were no significant differences (P > 0.05) in the variables IgG, fat, lactose, salts, TS, density, and pH between samples measured before and after lyophilization. There was a significant difference (P < 0.05) between the Brix average and the TP of the frozen and lyophilized colostrum samples. Lyophilization resulted in a small reduction (6.55%) in the IgG concentration measured by SRID. A strong positive correlation was observed between colostrum density and IgG concentration by SRID (r = 0.76) and between Brix and IgG concentration by SRID (r = 0.77). In the reconstitution test, the lyophilized colostrum was easily rehydrated in water, with full dilution, and remained stable. Lyophilization could be an alternative for the conservation of mare colostrum, since it is a very efficient process for retaining the physicochemical characteristics of the product, with minimal loss, particularly of IgG.

Assessment of specificity of dermatopathologic criteria for IgG4-related skin disease.

BACKGROUND: IgG4-related disease (IgG4-RD) represents a recently characterized multisystemic fibroinflammatory condition that can manifest a spectrum of skin findings (IgG4-related skin disease; IgG4-RSD). Histopathologic and immunohistochemical criteria have been proposed; however, the specificity of these criteria merits scrutiny given the potential histopathologic overlap of IgG4-RSD and both neoplastic and inflammatory skin conditions featuring lymphoplasmacytic infiltrates (IgG4-RSD mimics). This study sought to assess the specificity of the criteria by quantifying the frequency by which an expanded spectrum of IgG4-RSD mimics meet proposed thresholds. METHODS: Following IRB approval, a total of 69 cases of IgG4-RD mimics, representing 14 different diagnoses featuring plasma cells, were reviewed and analyzed for the following histopathologic and immunohistochemical features: (i) maximum IgG4+ count/high-powered field (hpf) >200; (ii) IgG4/IgG ratio >0.4 averaged over 3 hpfs; (iii) IgG4+ count >10 per hpf. RESULTS: Screening for IgG4-RSD by histopathologic criteria demonstrated the high frequency of lymphoplasmacytic infiltrates, contrasted with the rarity of storiform fibrosis (only one case of erythema elevatum diutinum [EED]) and obliterative phlebitis (0 cases). By immunohistochemical criteria, the analysis revealed that no cases exceeded 200 IgG4+ cells; 13% (9/69) cases demonstrated an IgG4/IgG ratio of >0.4 averaged over 3 hpfs; and 23% (16/69) cases demonstrated a mean IgG4+ count of >10 per hpf. CONCLUSION: Application of proposed IgG4-RSD histopathologic criteria to an expanded spectrum of potential IgG4-RSD mimics (to include cutaneous marginal zone lymphoma, syphilis, necrobiosis lipoidica, lichen sclerosus, ALHE, psoriasis, lymphoplasmacytic plaque, EED, and erosive pustular dermatosis), highlights the relative nonspecificity of lymphoplasmacytic infiltrates contrasted with the stringency of storiform fibrosis and obliterative fibrosis. Furthermore, an IgG4+ cell count of >10 per hpf and an IgG4/IgG ratio of >0.4 are not specific to IgG4-RSD alone. In the appropriate clinical context for IgG4-RSD, histopathologic features still represent the entry threshold for diagnosis consideration, which then allows for further screening by immunohistochemical criteria.

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.

Estimating the number of probable new SARS-CoV-2 infections among tested subjects from the number of confirmed cases.

OBJECTIVES: In most African countries, confirmed COVID-19 case counts underestimate the number of new SARS-CoV-2 infection cases. We propose a multiplying factor to approximate the number of biologically probable new infections from the number of confirmed cases. METHODS: Each of the first thousand suspect (or alert) cases recorded in South Kivu (DRC) between 29 March and 29 November 2020 underwent a RT-PCR test and an IgM and IgG serology. A latent class model and a Bayesian inference method were used to estimate (i) the incidence proportion of SARS-CoV-2 infection using RT-PCR and IgM test results, (ii) the prevalence using RT-PCR, IgM and IgG test results; and, (iii) the multiplying factor (ratio of the incidence proportion on the proportion of confirmed -RT-PCR+- cases). RESULTS: Among 933 alert cases with complete data, 218 (23%) were RT-PCR+; 434 (47%) IgM+; 464 (~ 50%) RT-PCR+, IgM+, or both; and 647 (69%) either IgG + or IgM+. The incidence proportion of SARS-CoV-2 infection was estimated at 58% (95% credibility interval: 51.8-64), its prevalence at 72.83% (65.68-77.89), and the multiplying factor at 2.42 (1.95-3.01). CONCLUSIONS: In monitoring the pandemic dynamics, the number of biologically probable cases is also useful. The multiplying factor helps approximating it.

A robust nanoscale RP HPLC-MS approach for sensitive Fc proteoform profiling of IgG allotypes.

The conserved region (Fc) of IgG antibodies dictates the interactions with designated receptors thus defining the immunological effector functions of IgG. Amino acid sequence variations in the Fc, recognized as subclasses and allotypes, as well as post-translational modifications (PTMs) modulate these interactions. Yet, the high similarity of Fc sequences hinders allotype-specific PTM analysis by state-of-the-art bottom-up methods and current subunit approaches lack sensitivity and face co-elution of near-isobaric allotypes. To circumvent these shortcomings, we present a nanoscale reversed-phase (RP) HPLC-MS workflow of intact Fc subunits for comprehensive characterization of Fc proteoforms in an allotype- and subclass-specific manner. Polyclonal IgGs were purified from individuals followed by enzymatic digestion releasing single chain Fc subunits (Fc/2) that were directly subjected to analysis. Chromatographic conditions were optimized to separate Fc/2 subunits of near-isobaric allotypes and subclasses allowing allotype and proteoform identification and quantification across all four IgG subclasses. The workflow was complemented by a semi-automated data analysis pipeline based on the open-source software Skyline followed by post-processing in R. The approach revealed pronounced differences in Fc glycosylation between donors, besides inter-subclass and inter-allotype variability within donors. Notably, partial occupancy of the N-glycosylation site in the CH3 domain of IgG3 was observed that is generally neglected by established approaches. The described method was benchmarked across several hundred runs and showed good precision and robustness. This methodology represents a first mature Fc subunit profiling approach allowing truly subclass- and allotype-specific Fc proteoform characterization beyond established approaches. The comprehensive information obtained paired with the high sensitivity provided by the miniaturization of the approach guarantees applicability to a broad range of research questions including clinically relevant (auto)antibody characterization or pharmacokinetics assessment of therapeutic IgGs.

An Investigation of the Suitability of Viscosity Detection in Estimating IgG Content in Mare Colostrum.

An adequate supply of colostrum is important for the prevention of hypogammaglobulinaemia in foals. In addition to the quantity of colostrum consumed and the time of consumption, the quality of the colostrum, the immunoglobulin (Ig) G concentration, is crucial. The aim of this study was to determine whether the viscosity of equine colostrum was a suitable estimate of IgG concentration. IgG content of colostrum was measured by ELISA and viscosity directly measured with a cone plate viscometer and indirectly assessed with a funnel. Analysis of 56 colostrum samples obtained from 40 mares at different postpartum time points was conducted to assess colostrum samples with varying levels of quality. The range of IgG concentrations determined by ELISA was 0.83 to 245.5 mg/mL (30.69 ± 41.92 mg/mL). The range of viscosity values determined by the cone plate method was 1.84 to 110.00 cP (7.86 ± 17.48 cP) at a shear rate of 3 rpm. Colostrum drainage from the funnel (drainage time), varied between 7.9 and 30.0 s, with an average of 9.96 ± 4.48 s. As the data were not normally distributed, Spearman's rank correlation analyses were calculated and significant correlation found between viscosity and IgG content (ρ = 0.71, P < .001), as well as between drainage time and IgG content (ρ = 0.75, P < .001). These correlations indicate that determining the viscosity of equine colostrum by cone plate or drainage time, may be an effective proxy measurement of IgG content.

Comparison of turbidometric immunoassay and brix refractometry to radial immunodiffusion for assessment of colostral immunoglobulin concentration in beef cattle.

BACKGROUND: Colostral immunoglobulin G (IgG) concentration is critical to the attainment of adequate transfer of passive immunity in cattle, however, studies comparing available tools for measurement of colostral IgG concentration in beef cattle are limited. OBJECTIVES: To report the agreement between 3 commercially available tests for evaluating IgG concentration in beef colostrum. ANIMALS: Two hundred six beef-breed cows hospitalized for calving management or dystocia. METHODS: Retrospective study to assess IgG of whole colostrum measured stall-side via turbidimetric immunoassay (TI) and brix refractometry (BRIX), compared to fat separated (FS) analysis via single radial-immunodiffusion (RID; reference standard), TI-FS and BRIX-FS. Test performance was assessed using Passing Bablock regression, Bland-Altman analysis, and area under the curve to determine optimal thresholds. RESULTS: Correlation between RID and TI-FS, BRIX-FS, or BRIX was similar (Spearman's ρ = 0.717, 0.715, 0.716, respectively) but correlation for TI was poor (ρ = 0.586). Regression analysis identified a substantial constant (-214.75 [CI: -272.03 to -178.07]) and proportional (13.24 [CI: 11.81-15.37]) bias between the RID and TI-FS which was similar for TI. TI-FS concentrations of 28.47, 38.75, and 50.62 g/L, BRIX-FS of ≤21.9%, ≤24.0%, and ≤27.4%, and BRIX of ≤21.3%, ≤23.8%, and ≤26.4% indicated IgG concentrations <50, <100, and <150 g/L, respectively; appropriate cutoffs for TI could not be generated. CONCLUSIONS AND CLINICAL IMPORTANCE: Both TI and TI-FS demonstrated a large constant and proportional bias compared to RID; BRIX and BRIX-FS were well correlated with RID and remain a reliable method for estimation of colostral IgG concentration in beef cattle.

Minerals and essential amino acids of bovine colostrum: Phenotypic variability and predictive ability of mid- and near-infrared spectroscopy.

Colostrum quality and volume are fundamental for calves because it is the primary supplier of antibodies and the first source of energy, carbohydrates, lipids, proteins, minerals, and vitamins for the newborn. Assessing the detailed composition (i.e., AA and mineral content) of bovine colostrum (BC) on-line and at a reasonable cost would help dairy stakeholders such as farmers or veterinarians for precision feeding purposes and industries producing preparations containing BC such as foodstuff, supplements, and medicaments. In the present study we evaluated mid- (MIRS) and near-infrared spectroscopy (NIRS) prediction ability for AA and mineral composition of individual BC. Second, we the investigated the major factors affecting the phenotypic variability of such traits also evaluating the correlations with the Ig concentration. Results demonstrated that MIRS and NIRS were able to provide sufficiently accurate predictions for all the AA. The coefficient of determination in external validation (R2V) fell, in fact, within the range of 0.70 to 0.86, with the exception of Ile, His, and Met. Only some minerals reached a sufficient accuracy (i.e., Ca, P, S, and Mg; R2V ≥ 0.66) using MIRS, and also S (R2V = 0.87) using NIRS. Phenotypically, both parity and calving season affected the variability of these BC composition traits. Heifers' colostrum was the one with the greatest concentration of Ca and P, the 2 most abundant minerals. These minerals were however very low in cows calving in summer compared with the rest of the year. The pattern of AA across parities and calving season was not linear, likely because their variability was scarcely (or not) affected by these effects. Finally, samples characterized by high IgG concentration were those presenting on average greater concentration of AA. Findings suggest that infrared spectroscopy has the potential to be used to predict certain AA and minerals, outlining the possibility of implementing on-site analyses for the evaluation of the broad-sense BC quality.

Evaluation of laboratory and on-farm tests to estimate colostrum quality for dairy cows.

The objectives of this study were to evaluate different analytical methods to determine colostrum quality in dairy cattle, including one laboratory-based method (ELISA) and 4 on-farm tests. We hypothesized that the colostral IgG concentration using different analytical methods, such as ELISA (mg/mL), digital Brix refractometer (% Brix), colostrometer (specific gravity and mg/mL), an outflow funnel (seconds), and a lateral flow assay (mg/mL), were highly correlated with the reference method, radial immunodiffusion (RID; mg/mL) and would generate comparable results. Colostrum samples were collected from 209 Holstein Friesian cows on 2 commercial dairy farms in Germany. Colostrum weight and colostrum temperature were measured. Test characteristics, such as optimum thresholds, sensitivity, specificity, and area under the curve (AUC) were determined using a receiver operating characteristic curve analyses for each test. Out of 209 colostrum samples assessed by RID, 186 (89%) samples had high quality (≥50 mg IgG/mL), while 23 colostrum samples (11%) showed poor quality with IgG concentrations less than 50 mg/mL. The mean IgG concentration (±SD) was 101.3 ± 45.9 mg/mL and the range was 6.0 to 244.3 mg/mL. The Pearson correlation coefficient (r) between RID and ELISA was r = 0.78. In comparison to RID, Pearson correlation coefficients for the on-farm tests were: r = 0.79 (digital Brix refractometry), r = 0.58 (colostrometer: specific gravity), r = 0.61 (colostrometer: temperature corrected), r = 0.26 (outflow funnel) and r = 0.43 (lateral flow assay), respectively. The optimal threshold to identify high-quality colostrum using ELISA was 50.8 mg/mL with sensitivity 91.3%, specificity 92.3%, and AUC of 0.94. For the on-farm tests sensitivity ranged from 95.7% (Brix refractometry) to 60.9% (lateral flow assay). Specificity ranged from 88.6% (lateral flow assay) to 75.9% (colostrometer: temperature corrected). The AUC ranged from 0.93 (Brix refractometry) to 0.73 (outflow funnel). Based on the AUC, ELISA (0.94) and Brix refractometry (0.93) can be considered highly accurate. In conclusion, the ELISA is accurate to assess colostrum quality. Regarding the on-farm tests only the digital Brix refractometer and the colostrometer were adequate to determine colostrum quality.

Convergence insufficiencyCentral mini-plication of medial rectusDiplopiaConsecutive esotropiaSurgical overcorrection / Detection of anti-SARS-CoV-2 antibodies in tears: Ocular surface immunity to COVID-19

Objetivos Evaluar la presencia de anticuerpos IgA e IgG específicos del SARS-CoV-2 en lágrima de sujetos no vacunados y vacunados contra la COVID-19 con antecedentes de infección SARS-CoV-2. Correlacionar los resultados en lágrima con los de saliva y sangre, datos clínicos y regímenes de vacunación. Métodos Estudio transversal que incluyó a sujetos con antecedentes de infección SARS-CoV-2, tanto no vacunados como vacunados contra la COVID-19. Se recogieron 3muestras: lágrima, saliva y sangre. Se analizaron IgA e IgG frente a S-1 SARS-CoV-2 con ELISA semicuantitativo. Resultados Treinta sujetos, con una edad media 36,4±10, varones 13/30 (43,3%) con historia de infección SARS-CoV-2 leve; 13/30 (43,3%) habían recibido un régimen de 2 dosis y 13/30 (43,3%) un régimen de 3 dosis de vacunación anti-COVID-19, 4/30 (13,3%) no estaban vacunados. Todos los sujetos con vacunación completa presentaron IgA detectable en los 3biofluidos. Entre los no vacunados, se detectó IgA en 3/4 sujetos en lágrima y saliva, mientras que no se detectó IgG. No se observaron diferencias entre la pauta de vacunación de 2 y 3 dosis según los títulos IgA-IgG. Conclusiones Anticuerpos IgA e IgG del SARS-CoV-2 están presentes en lágrimas de pacientes con antecedentes de COVID-19 leve, lo que destaca el papel de la superficie ocular como primera línea de defensa frente a la infección. La mayoría de los sujetos no vacunados presentaron IgA a largo plazo en lágrima y saliva. La inmunización híbrida (infección natural más vacunación) parece potenciar las respuestas IgG mucosas y sistémicas. No se observaron diferencias entre la pauta de 2 y 3 dosis (AU)

Purpose To evaluate the presence of SARS-CoV-2 specific IgA and IgG antibodies in tears of unvaccinated and anti-COVID-19 vaccinated subjects with previous history of SARS-CoV-2 infection. To compare results in tears with those in saliva and serum and correlate with clinical data and vaccination regimens. Methods Cross-sectional study including subjects with a previous history of SARS-CoV-2 infection, both unvaccinated and vaccinated against COVID-19. Three samples were collected: tears, saliva and serum. IgA and IgG antibodies against S-1 protein of SARS-CoV-2 were analyzed with a semi-quantitative ELISA. Results Thirty subjects, mean age 36.4±10, males 13/30 (43.3%) with history of mild SARS-CoV-2 infection were included. 13/30 (43.3%) subjects had received a 2-dose regimen and 13/30 (43.3%) a 3-dose regimen of anti-COVID-19 vaccine, 4/30 (13.3%) subjects were unvaccinated. All the participants with full anti-COVID-19 vaccination (2-or 3-doses) presented detectable anti-S1 specific IgA in all 3biofluids, tears, saliva and serum. Among unvaccinated subjects, specific IgA was detected in 3/4 subjects in tears and saliva, whereas IgG was not detected. Considering IgA and IgG antibodies titers, no differences were observed between the 2- and 3-dose vaccination regimen. Conclusions SARS-CoV-2-specific IgA and IgG antibodies were detected in tears after mild COVID-19, highlighting the role of the ocular surface as a first line of defense against infection. Most naturally infected unvaccinated individuals exhibit long-term specific IgA in tears and saliva. Hybrid immunization (natural infection plus vaccination) appears to enhance mucosal and systemic IgG responses. However, no differences were observed between the 2- and 3-dose vaccination schedule (AU)