Colostral Antibodies Research Articles

New Application of Indirect Fluorescent Antibody (IFA) Technique Using Latex Particles Coupled with Verotoxin 2 from Escherichia Coli O157:H7 in Order to Determine Colostral Antibody Titers in Immunized Dairy Cows

A simple and novel assay method for determining colostral and serum against soluble verotxin 2 (VT2) titers by indirect fluorescent antibody (IFA) assay using latex sensitized with VT2 was devised. The latex particles did not auto-fluoresce, and non specific reactions disappeared after washing with phosphate buffered saline containing 3 M Nacl. The highest titer measured by neutralizing test was observed at 1 day after delivery. The highest titer for each immunoglobulin class measured by enzyme-linked immunosorbent assay (ELISA) or IFA using latex sensitized with VT2 was also observed at 1 day after delivery. The changes in titer measured by each method showed similar patterns. Furthermore, the titers for IgG antibody were higher than those for IgM or IgA antibodies. Thus, the titers of bovine immune colostral antibody and each immunoglobulin class could be measured by IFA using latex sensitized with VT2.

Research of immune response in unvaccinated piglets against porcine circovirus type 2

Infection of pigs caused by porcine circovirus type 2 (PCV2) is present throughout the world. The aim of this study was to determine, based on the follow-up of the class IgG titers in piglets and fattening pigs, the duration of colostral immunity against infections in pigs caused by PCV2. The study included 28 piglets, whose titer was determined by using indirect ELISA test in intervals up to 110 days of age. The observed average values of IgG in piglets aged 21 days (8.47 log2) and 35 days (6.69 log2) in our surveys indicate very high titers of maternal antibodies, and that the piglets at this age are, to some extent, protected from infection caused by PCV2. Absence of the specific anti PCV2 antibodies was determined in 14.29% (21 days old) and 15.38% (35 days old) piglets at this age. The average titer of antibodies, specific for PCV2, in blood serum of piglets on the 50th day decreased to 3.74 log2, what indicates that in the majority of piglets (61.54%) catabolism of colostral antibodies occurred. On the 80th day of the piglets life there were no seropositive specimens, which unambiguously indicates that in this age, there was a complete catabolism of colostral antibodies and the disappearance of passive immunity. In all the 110 days? old fattening pigs, an average antibody titer recorded a sharp rise (12.78 log2). Possible reasons for this sudden increase in PCV2 antibody titers in the blood serum of fattening pigs is is a widespread presence of this infection in our region, as well as the fact that there exists a part of pigs population which is not immune to PCV2 infection. The results of this research are important for choosing the optimal moment for vaccination, considering that high titers of colostral antibodies of class G on the 21st and 35th day of piglets? life have been proven. This data points out to a possible interference with vaccine immunogens in the case of vaccination in this particular age.

Neonatale iso-erytrolyse bij de kat

Neonatale iso-erytrolyse bij kittens kan enkel voorkomen wanneer de moederpoes bloedgroep B en de kater bloedgroep A of AB heeft. De eerste 24 uur na de geboorte is de darmbarrière bij een kitten open, waardoor na het zuigen antistoffen uit het colostrum in de bloedbaan kunnen opgenomen worden. Een kitten met bloedgroep A neemt anti-A-antistoffen op, waardoor zijn eigen erytrocyten vernietigd worden. Bij symptomen, zoals anemie, hemoglobinurie en icterus, is een bloedtransfusie vaak noodzakelijk. Toch blijft het sterftepercentage heel hoog en is preventie uitermate belangrijk. Daarom dient de bloedgroep van risicorassen steeds vóór het fokken te worden bepaald. Het is af te raden om te fokken met een moederpoes met bloedgroep B en een kater met bloedgroep A of AB. Indien dit wel gebeurt, dient men de kittens 24 uur weg te halen bij de moederpoes, ze te voeden met kunstmelk en subcutaan of oraal serum van een goed geïmmuniseerde poes met bloedgroep A toe te dienen.

No detectable precolostral antibody response in calves born from cows with cotyledons positive for Coxiella burnetii by quantitative PCR

Samples from 45 dams (milk/colostrum, faeces, vaginal fluid and blood on days 171-177 of gestation and at parturition, and cotyledons at parturition) and their calves (blood collected before colostrum intake and weekly until days 29-35) were analysed to examine the vertical transmission of Coxiella burnetii and links between shedding and seropositivity. All calves were born C. burnetii seronegative. Only those born to seropositive dams seroconverted following colostrum intake. Logistic regression analyses indicated that the likelihood of dam seropositivity was 21 and 4.85 times higher for multiparous than for primiparous (65.6% vs. 8.3%, P = 0.006) and for prepartum shedding cows (75% vs. 38.2%, P = 0.03) compared to the remaining animals, respectively. In conclusion, the results of this study indicate no detectable precolostral antibody response in calves born from dams with cotyledons positive for C. burnetii by qPCR. In order to analyse the possibility of persistent infection due to immunotolerance to an early in utero infection, further studies will need to test for C. burnetii DNA. In addition, in the present study multiparous cows showed a significantly higher seroprevalence than primiparous cows and heifers, colostral antibodies were efficiently transferred to newborn calves, and there was a link between bacterial shedding on days 171-177 of gestation and Coxiella seropositivity of the dam.

Evaluation of diagnostic methods to distinguish between calves persistently and transiently infected with bovine viral diarrhoea virus in respect to the presence of maternal antibodies

Abstract Two issues concerning virus detection and identification of persistently infected (PI) cattle were analysed in the study: 1) interference by maternal antibodies and 2) discrimination between PI and transiently infected (TI) animals. Antigen ELISA and RT-PCR based methods were compared using serum samples from natural and experimental PI and TI calves. RT-PCR and realtime RT-PCR using primers within 5’UTR region were more sensitive in detecting PI animals than Erns and NS3 antigen capture ELISAs, and they were not influenced by the presence of colostral antibodies in serum or by bovine viral diarrhoea virus genotype. The serum samples with Ct values ≤ 29.10 (corresponding to 104.87 viral RNA copies/μL) identified PI animals with 100% probability, while all samples with Ct values > 32.06 (corresponding to viral RNA load below 104 copies/μL) indicated TI status. The samples with Ct values between 29.10 and 32.06 (17.2% of PI and 11.5% of TI) should be considered as PI suspect and retested.

Transfer of Cystoisospora suis-specific colostral antibodies and their correlation with the course of neonatal porcine cystoisosporosis

Cystoisospora suis is the most pathogenic species of coccidia in suckling piglets, affecting them predominantly within their first three weeks of life. The clinical signs of neonatal cystoisosporosis include watery diarrhea and wasting, leading to significant economic losses for the farmer. Since neonatal piglets have an immature immune system, colostral transfer of maternal factors such as immune cells or antibodies is essential for controlling infections at that age. However, the role of C. suis-specific antibodies transferred from the sow to the piglets and possible correlations between antibody levels in the piglets acquired from colostrum with the clinical outcome of disease are currently not understood. To address this issue, 12 non-infected piglets and 14 piglets experimentally infected with C. suis on the third day of life were examined during their first four weeks of life. IgG, IgA, and IgM titers in the blood serum specific for sporozoites and merozoites of C. suis were evaluated, along with oocyst excretion and fecal consistency. Additionally, the antibody content in the colostrum and milk of three mother sows was determined. A transfer of naturally acquired C. suis-specific antibodies from sows to piglets with the colostrum could be demonstrated. Maternal antibodies in piglets’ blood sera did not persist for longer than 14–21 days except for IgG which was present in high titers until the end of the study. Within 2–3 weeks after birth the onset of endogenous antibody production was noticed. Titers in blood serum showed a correlation with the severity of diarrhea which was positive for IgG and IgM (possibly due to increased consumption or loss of these antibodies) and negative for IgA. C. suis-specific mucus antibodies isolated from infected and non-infected piglets (n=6/group) on the 28th day of life were present in both groups, showing significantly higher titers of IgA and IgM in infected piglets. Maternally transferred antibodies acquired by natural infections of sows as observed in this study did not provide protection against the clinical manifestation of disease. The level and effect of transferrable maternal factors necessary for protection still need to be elucidated. However, correlations between antibody titers and fecal consistency in the piglets indicate that C. suis-specific antibodies might be useful markers for the expectable clinical severity of cystoisosporosis.

Humoral response and colostral antibody transfer following ‘one-dose’ pre-mating vaccination of sows against porcine circovirus type-2

The objective of this study was to investigate the presence of porcine circovirus type 2 (PCV2) DNA and antibody to the virus in the serum and colostrum of sows vaccinated prior to mating and in their offspring. Seventy-seven sows were randomly distributed into vaccinated (V, n=36) and non-vaccinated (NV, n=41) groups. One week before mating, sows were given a PCV2 vaccine (V group) or PBS (NV group) IM. Blood samples were taken from the sows at fixed time-points and colostrum samples were taken at farrowing. Blood samples were also taken from the piglets of the sows at 4weeks of age. The results indicated that vaccination prior to mating elicited a strong, homogeneous humoral response and, in consequence, more homogeneous colostral PCV2 antibody concentrations.

Dynamics of antibody response and viraemia following natural infection of porcine circovirus 2 (PCV‐2) in a conventional pig herd

Porcine circovirus 2 (PCV-2) is a primary agent of post-weaning multi-systemic wasting syndrome (PMWS), ubiquitous in pig herds. The course of viraemia and seroconversion in naturally infected pigs were investigated in piglets from the 2nd week of their life. Piglets were divided into seropositive (Ab(+)) and seronegative (Ab(-)) groups. Subsequently, after vaccination against PCV-2 (Ingelvac(®) CIRCOFLEX™, Böehringer Ingelheim), they were further divided into non-vaccinated seronegative (NVAC/Ab(-)) and seropositive (NVAC/Ab(+)), and vaccinated seronegative (VAC/Ab(-)) and seropositive (VAC/Ab(+)). PCV-2 colostral antibodies failed to prevent development of natural PCV-2 infection in conventional piglets; however, this occurred at a higher age in comparison with seronegative pigs. Neither colostral nor post-infection antibodies prevented development of viraemia, which persisted up to the end of the study (the 19th week), but without clinical signs of PMWS. Vaccination failed to prevent development of natural PCV-2 infection, but viraemia was limited to between the 8th and 10th week. The presence of colostral anti-PCV-2 antibodies did not show any untoward effect to vaccination; on the contrary, VAC/Ab(+) animals showed the lowest titre of viraemia.

Interference of colostral antibodies with response to a Bluetongue serotype 8 inactivated vaccine in lambs born from hyperimmune ewes

Despite the widespread use of Bluetongue serotype 8 (BTV-8) vaccines across Europe, there remain unanswered questions on the effects of maternally derived antibodies (MDA) on vaccination. This study investigated the persistence of MDA in lambs and their interference on vaccine efficacy. Lambs born from hyperimmune ewes–i.e. ewes naturally infected with BTV-8 in 2007 and repeatedly vaccinated thereafter–were used. They were allocated to five groups (n=7/group), four receiving a BTV-8 vaccine at different ages (3, 5, 7 and 9 months) and one left unvaccinated. Vaccine protection was assessed upon a BTV-8 challenge performed at 10 months of age. The neutralising antibody titres were also measured throughout the study. Vaccination at 5, 7 and 9 months led to seroconversion and full clinical and virological protection in all animals. Among lambs vaccinated at 3 months, three (3/7) did not respond to vaccination and were not protected from challenge infection. Others animals (4/7) were fully protected from clinical disease and viraemia in accordance with their seropositive status at time of challenge. In our very stringent conditions, MDA hampered response to BTV-8 vaccination in lambs for at least 3 months after birth. Accordingly, the optimal age of vaccination needs to be adjusted to the immune status of the sheep population.

Immunisation of mares with binding domains of toxinsAandBofClostridium difficileelicits serum and colostral antibodies that block toxin binding

Enterocolitis caused by Clostridium difficile (C. difficile) is a serious, sometimes fatal, disease of neonatal foals and older horses. Toxins A and B (TcdA and B) produced by C. difficile are important virulence factors. Immunisation of mares with receptor binding domains of toxins may prevent or reduce the severity of C. difficile colitis in foals. To determine whether antibodies generated in the pregnant mare to the binding regions of TcdA and B will neutralise TcdA and B toxicity. Sequences encoding the binding domains of each toxin were isolated by PCR amplification from C. difficile JF09, a foal isolate, and cloned and expressed into pET15b. Thirteen mares were immunised twice 2 weeks apart with 200 μg of each recombinant protein with Quil A 2 months prior to foaling. Antibodies were assayed in the sera and colostrum by ELISA and for ability to block the cytopathic activity of each of toxin for equine endothelial cells. All mares produced strong serum antibody responses to the binding domain of each toxin. A high level of toxin-specific antibodies was also detected in colostrum and in most foal sera 2 days after suckling. Diluted sera and colostrum premixed with either TcdA or B had no effect on the morphology of equine endothelial cells. Application of the same concentration of toxins alone or premixed with nonimmune mare/foal serum or colostrum led to an unambiguous cytopathic effect that ranged from complete degradation to varying degrees of cell rounding. Immunisation of pregnant mares with recombinant binding domains of TcdA and B of C. difficile resulted in the production of specific antibodies in serum and colostrum that blocked the cytopathic activity of toxins. Results of studies support the feasibility of a prepartum vaccine against C. difficile enterocolitis in foals.

Demonstration of early functional compromise of bone marrow derived hematopoietic progenitor cells during bovine neonatal pancytopenia through in vitro culture of bone marrow biopsies

BackgroundBovine neonatal pancytopenia (BNP) is a syndrome characterised by thrombocytopenia associated with marked bone marrow destruction in calves, widely reported since 2007 in several European countries and since 2011 in New Zealand. The disease is epidemiologically associated with the use of an inactivated bovine virus diarrhoea (BVD) vaccine and is currently considered to be caused by absorption of colostral antibody produced by some vaccinated cows (“BNP dams”). Alloantibodies capable of binding to the leukocyte surface have been detected in BNP dams and antibodies recognising bovine MHC class I and β-2-microglobulin have been detected in vaccinated cattle. In this study, calves were challenged with pooled colostrum collected from BNP dams or from non-BNP dams and their bone marrow hematopoietic progenitor cells (HPC) cultured in vitro from sternal biopsies taken at 24 hours and 6 days post-challenge.ResultsClonogenic assay demonstrated that CFU-GEMM (colony forming unit-granulocyte/erythroid/macrophage/megakaryocyte; pluripotential progenitor cell) colony development was compromised from HPCs harvested as early as 24 hour post-challenge. By 6 days post challenge, HPCs harvested from challenged calves failed to develop CFU-E (erythroid) colonies and the development of both CFU-GEMM and CFU-GM (granulocyte/macrophage) was markedly reduced.ConclusionThis study suggests that the bone marrow pathology and clinical signs associated with BNP are related to an insult which compromises the pluripotential progenitor cell within the first 24 hours of life but that this does not initially include all cell types.

Colostrum of Healthy Mothers Contains Broad Spectrum of Secretory IgA Autoantibodies

Human colostrum and milk provide a newborn with immunomodulatory components, ensuring protection and proper development of the immune system. Secretory IgA antibodies in colostrum represent the first line of defence against harmful substances, but their potential spectra of reactivity with autoantigens remains unclear. Here, we characterised the repertoire of natural sectretory IgA autoantibodies in colostrum of healthy mothers. The human colostrum samples from 39 healthy mothers were analyzed for autoantibodies by indirect immunofluorescence, dot blots, immunoblots and ELISA. We found that there is high diversity in reactivities of colostral IgA antibodies to autoantigens among individual samples. Using tissue sections and biochips commonly used for autoimmunity testing, we found that most samples reacted with monkey ovary (79.3%), monkey pancreatic tissue (78.6%), human HEp-2 cells (69%) and monkey adrenal gland (69.0%), fewer samples reacted with monkey liver tissue (47.2%), rat stomach (42.9%), monkey testicular tissue (41.4%), monkey salivary gland (39.3%), rat kidney (32.1%) and monkey cerebellar tissue (17.9%). At the protein level, we detected reactivity of IgA with 21 out of 25 (auto) antigens. The majority of the samples reacted with the pyruvate dehydrogenase complex, E3 ubiquitin ligase, cytosolic liver antigen, promyelocytic leukemia protein and nuclear pore glycoprotein-210. Using ELISA, we found reactivity of colostral IgA antibodies against examined extractable nuclear antigens, double stranded DNA, phospholipids and neutrophil cytoplasm. The broad spectrum of polyreactive natural autoantibodies present in human colostrum may contribute to proper development of mucosal immune system of the breastfed infant.

Transient elimination of circulating bovine viral diarrhoea virus by colostral antibodies in persistently infected calves: a pitfall for BVDV-eradication programs?

Infections with bovine viral diarrhoea virus (BVDV) cause substantial economic losses to cattle industries. Rapid detection of persistently BVDV infected (PI) calves is of utmost importance for the efficacy of BVDV control programs. Blood and ear skin biopsy samples are conveniently used for early mass screening of newborns. However, little is known about the impact of colostral antibodies on the outcome of relevant analyses. Here, we rigorously tested a series of samples obtained from five colostrum-fed PI calves from birth until they reached the status of seronegativity for NS3-specific antibodies. We comparatively quantified virus loads in blood samples and dried skin biopsies as detected with BVDV-NS3-, -Erns-capture ELISA and RT-qPCR. Monitoring of NS3-positive leukocytes was done with flow cytometry. Within seven days after colostrum intake, BVDV infected leukocytes disappeared for a three- to eight-week period. Immediately after colostrum ingestion, detectable Erns antigen levels dropped 10–100-fold in biopsy samples and in sera detection of Erns failed for one to two weeks. Virus demonstration in biopsy samples with a NS3-antigen-ELISA failed until days 90–158 after birth. Specific antibodies against BVDV also impaired the detection of viral RNA in leukocytes and blood. Mean RNA levels of the five calves were reduced in sera 2.500-fold and in leukocytes 400-fold, the lowest values were at week three of live. In contrast, levels of measurable viral RNA in biopsy samples remained constant during the observation period.

ATIVIDADE VIRAL DO VÍRUS RESPIRATÓRIO SINCICIAL BOVINO (BRSV) EM BEZERROS LEITEIROS

Bovine respiratory syncytial virus (BRSV) is one of the major pathogens affecting the respiratory system of young cattle, causing serious economic losses. Data on its epidemiology and occurrence in animals under one-year of age are still scarce in the literature. This study aimed to determine the occurrence of viral activity in three of BRSV seropositive dairy herds (A, B, and C), by serological monitoring of calves from the first day of life until the age of one year, by virus neutralization test. Results showed that in animals from farms A and B, antibody titers increased in the first month, characterizing passive transfer of immunity through colostrums. Over time, the titers decreased till total absence in the sixth and eighth months respectively and then antibodies titration increased in the final months of the study, probably due to natural infection. On property C, although there was a similar antibodies’ dynamics to the others, a period of total absence did not occurred, suggesting that animals may have been infected in the first months of life, despite the presence of colostral antibodies. This study demonstrated fluent BRSV activity amongst animals in all properties.KEYWORDS: antibody titer; bovine respiratory syncytial virus; screening; viral activity; virus neutralization.

Vaccination of pregnant cows with EspA, EspB, γ-intimin, and Shiga toxin 2 proteins from Escherichia coli O157:H7 induces high levels of specific colostral antibodies that are transferred to newborn calves

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of intestinal disease and hemolytic uremic syndrome, a serious systemic complication that particularly affects children. Cattle are primary reservoirs for EHEC O157:H7 and the main source of infection for humans. Vaccination of cattle with different combinations of bacterial virulence factors has shown efficacy in decreasing EHEC O157:H7 shedding. It is, therefore, important to demonstrate whether vaccination of pregnant cows with EHEC O157:H7 induces high titers of transferable antibodies to avoid early colonization of calves by the bacteria. In this study we evaluated the ability of EspA, EspB, the C-terminal fragment of 280 amino acids of γ-intimin (γ-intimin C280) and inactivated Shiga toxin (Stx) 2 proteins to induce specific antibodies in colostrum and their passive transference to colostrum-fed calves. Friesian pregnant cows immunized by the intramuscular route mounted significantly high serum and colostrum IgG responses against EspB and γ-intimin C280 that were efficiently transferred to their calves. Antibodies to EspB and γ-intimin C280 were detected in milk samples of vaccinated cows at d 40 postparturition. Significant Stx2-neutralizing titers were also observed in colostrum from Stx2-vaccinated cows and sera from colostrum-fed calves. The results presented showed that bovine colostrum with increased levels of antibodies against EHEC O157:H7 may be obtained by systemic immunization of pregnant cows, and that these specific antibodies are efficiently transferred to newborn calves by feeding colostrum. Hyperimmune colostrum and milk may be an alternative to protect calves from early colonization by EHEC O157:H7 and a possible key source of antibodies to block colonization and toxic activity of this bacterium

Comparison of efficacies of bovine immune colostral antibody and each immunoglobulin class against verotoxin 2, flagellum and somatic cells of Escherichia coli O157:H7 in mice

The efficacy of bovine immune colostral (colostral) antibodies against verotoxin (VT) 2, flagellum and somatic cells of Escherichia coli (E. coli) O157:H7 in mice was determined. Three major immunoglobulin (Ig) classes were isolated from the colostral antibody against VT2 by affinity chromatography and were used for estimation. Mice inoculated with VT2 were administered each Ig class from the colostral antibody, colostral antibody (colostral whey containing antibody) or serum antibody against VT2 at 1 hour after VT2 inoculation. All control mice (20/20) died after administration of sterilized saline instead of the colostral antibody. The survival rate was 93.3% (14/15) after administration of S-IgA or IgM antibody, or colostral antibody. Survival rates for IgG antibody and serum antibody administration were 80% (12/15) and 60% (9/15), respectively. Serum concentrations of VT2, which was absorbed from the small intestine in mice after administration of VT2 and colostral antibody, were measured by fluorescence enzyme immunoassay (FEIA). Serum concentrations of VT2 after administration of colostral antibody were lower than those after administration of sterilized saline. Mice inoculated with VT2-producing E. coli 157:H7 were administered anti-flagellum or anti-somatic colostral antibodies. Survival rates for E. coli O157:H7-infected mice administered the anti-flagellum and anti-somatic colostral antibodies were 52.4% (11/21) and 22.2% (4/18), respectively. Furthermore, survival rates increased to 89.5% (17/19) with combined administration of anti-flagellum and anti-VT2 colostral antibodies. These results suggest that colostral antibodies against VT2, flagellum and somatic cells are effective against E. coli O157:H7 infection.

Passive and active immunity against parvovirus infection in piglets

The aim of this study was to come to a closer understanding of the origination, dynamics of movement and cessation of colostral immunity to parvovirus infection in swine (PPV) on the basis of an analysis of antibody titres in the blood serum of piglets in their first 6 months. On the third day of life in the blood serum of newborn piglets, an average antibody titer of 13.37 was recorded. An antibody level of 13.30 was maintained until the 10 th day of life, when it started to decline to 12.02 on the seventeenth and to 11.80 on the twenty-fourth day of life. A seronegative result was ascertained on the 38 th and 45 th day of life (8.40 and 5.48). On the 55 th day of life, the titer increased to 10.86 and slowly continued to rise to 11.61 on the 180 th day of life. Because negative results are the sign of a complete catabolism of colostral antibodies whose absorption was completed in the first 2 to 3 days of life, the antibodies recorded on the 55 th day are to be considered as a result of active immunological reaction formed between 31 st and 55 th day of life. The research was done on 60 piglets descending from vaccinated mothers and it was expected of the piglets to obtain enough immunity through colostrum which would protect them against PPV infection until they developed their own immunological response. On the basis of the given results, we conclude that colostral immunity to parvovirus infection in swine lasts for about one month and that antibodies found in the blood serum of piglets after the first month of life are a result of the activation of the immune system. Keywords: Porcine parvovirus, colostral immunity, reproductive efficiency, antibody

Serum and Colostral Antibody Responses of Pregnant Mares to Salmonella Bacterins and Colostral Antibody Transfer to Their Foals

Salmonella spp. are well-recognized foal pathogens. However, prevention of neonatal salmonellosis by vaccinating pregnant mares has not been reported previously. A formalinized adjuvanted bacterin of Salmonella enterica, serovar typhimurium (S typhimurium) and serovar newport (S newport), was given to pregnant mares to determine its safety (study 1) and potency in enhancing Salmonella-specific antibody for colostral transfer to foals (study 2). Antibody levels to S typhimurium (lysate and lipopolysaccharide [LPS]) and S newport (lysate) were determined by enzyme-linked immunoassay and reported as optical density measures. The mares in study 1 (n = 16) exhibited minimal reactions to the bacterin, and pregnancy was maintained in all mares throughout the study period. In study 2, serum antibody levels to both S typhimurium and S newport increased significantly in vaccinated mares (mean OD increase: 0.83 ± 0.58 [lysate of S typhimurium], 1.27 ± 0.82 [LPS of S typhimurium], and 0.67 ± 0.74 [lysate of S newport], respectively; n = 28). Elevated serum antibody levels on day 28 correlated with high antibody levels in colostrum (r2 = 0.62-0.75; P < .0001) and in serum samples of foals (r2 = 0.5-0.73; P < .001).

Cinética dos anticorpos de origem colostral contra a toxina épsilon de Clostridium perfringens tipo D em cordeiros

Enterotoxemia, uma das mais importantes enfermidades que acomete os pequenos ruminantes domésticos, é causada principalmente pela toxina épsilon de Clostridium perfringens tipo D. O presente estudo avaliou a cinética de anticorpos colostrais antitoxina épsilon em cordeiros nascidos de ovelhas submetidas a dois diferentes tipos de manejo sanitário. Um grupo de ovelhas prenhes (n=6) foi vacinado com uma dose única de vacina comercial polivalente contra clostridioses contendo toxóide épsilon na sua formulação cerca de 30 dias antes da data prevista para a parição. Outro grupo de ovelhas (n=6) de mesma idade gestacional não foi vacinado. Imediatamente após o parto, antes da ingestão do colostro, foram colhidas amostras sanguíneas dos respectivos cordeiros, bem como aos 30 e 60 dias de idade e submetidas à avaliação sorológica pelo teste de ELISA indireto. Os resultados encontrados permitem concluir que a vacinação de ovelhas prenhes 30 dias antes do parto contra a enterotoxemia causada pela toxina épsilon, com dose única de produto comercial, induz imunidade passiva em níveis considerados protetores (&gt;0,5UI/ml) aos cordeiros por, no mínimo, 60 dias de idade.

Genomic and proteomic characterization of SuMu, a Mu-like bacteriophage infecting Haemophilus parasuis

BackgroundHaemophilus parasuis, the causative agent of Glässer’s disease, is prevalent in swine herds and clinical signs associated with this disease are meningitis, polyserositis, polyarthritis, and bacterial pneumonia. Six to eight week old pigs in segregated early weaning herds are particularly susceptible to the disease. Insufficient colostral antibody at weaning or the mixing of pigs with heterologous virulent H. parasuis strains from other farm sources in the nursery or grower-finisher stage are considered to be factors for the outbreak of Glässer’s disease. Previously, a Mu-like bacteriophage portal gene was detected in a virulent swine isolate of H. parasuis by nested polymerase chain reaction. Mu-like bacteriophages are related phyologenetically to enterobacteriophage Mu and are thought to carry virulence genes or to induce host expression of virulence genes. This study characterizes the Mu-like bacteriophage, named SuMu, isolated from a virulent H. parasuis isolate.ResultsCharacterization was done by genomic comparison to enterobacteriophage Mu and proteomic identification of various homologs by mass spectrometry. This is the first report of isolation and characterization of this bacteriophage from the Myoviridae family, a double-stranded DNA bacteriophage with a contractile tail, from a virulent field isolate of H. parasuis. The genome size of bacteriophage SuMu was 37,151 bp. DNA sequencing revealed fifty five open reading frames, including twenty five homologs to Mu-like bacteriophage proteins: Nlp, phage transposase-C-terminal, COG2842, Gam-like protein, gp16, Mor, peptidoglycan recognition protein, gp29, gp30, gpG, gp32, gp34, gp36, gp37, gpL, phage tail tube protein, DNA circulation protein, gpP, gp45, gp46, gp47, COG3778, tail fiber protein gp37-C terminal, tail fiber assembly protein, and Com. The last open reading frame was homologous to IS1414. The G + C content of bacteriophage SuMu was 41.87% while its H. parasuis host genome’s G + C content was 39.93%. Twenty protein homologs to bacteriophage proteins, including 15 structural proteins, one lysogeny-related and one lysis-related protein, and three DNA replication proteins were identified by mass spectrometry. One of the tail proteins, gp36, may be a virulence-related protein.ConclusionsBacteriophage SuMu was characterized by genomic and proteomic methods and compared to enterobacteriophage Mu.