PubMed Health⌕ Search

Biomedical subjects

W L Mengeling

Publications and source records attributed to W L Mengeling.

At least 73 records · Page 4Linked to original sources
PubMed1986

Vaccination of swine with an inactivated porcine parvovirus vaccine in the presence of passive immunity.

A study was conducted to determine whether low hemagglutination inhibiting (HI) titers (1:5) for porcine parvovirus (PPV) block the development of immune response to a PPV vaccine. Pigs with low (1:5), medium (1:10 or 1:20), or high (1:40 or 1:80) titers were obtained by IV injections with various amounts of PPV immune serum. Pigs were inoculated with 1 or 2 doses of vaccine and were monitored for serum HI antibodies to PPV. Pigs with low titers responded to vaccine just as well as did the seronegative pigs. The HI titers of pigs with medium titers did not increase after first vaccination. After the second vaccination, however, their titers increased and were similar to those of pigs with low titers. High titers blocked the response to vaccination. The pigs that received 2 doses of vaccine had higher titers than did those of pigs that received 1 dose of vaccine. The results indicated that low titers, which would be expected in gilts at the time of vaccination, do not interfere with immunization by the inactivated PPV vaccine, and that 2 doses of vaccine may provide better and longer lasting immune response to inactivated PPV vaccine and probably longer lasting immunity against PPV-induced reproductive failure.

Animals↗
PubMed1986

Antigenic relationships among autonomous parvoviruses.

The antigenic relatedness of minute virus of mice (MVM), Kilham rat virus (KR), H-1 virus (H-1), haemorrhagic encephalopathy of rats virus (HER), porcine parvovirus (PPV), canine parvovirus (CPV), feline panleukopenia virus (FPV), goose parvovirus (GPV) and bovine parvovirus (BPV) was studied by immunofluorescence microscopy (FA) and by serum neutralization (SN). An antigenically related group comprising MVM, KR, HER, PPV, CPV and FPV was recognized by FA and most reactions within the group were reciprocal. Antigenic relatedness was less evident when the same viruses and antisera were tested by SN. Only CPV and FPV were closely and reciprocally related. Other cross-reactions by SN were quantitatively minor and included neutralization of CPV and FPV by pig anti-PPV serum and neutralization of H-1 and HER by rat anti-KR serum. Neither FA nor SN revealed any antigenic relationship of BPV and GPV either with each other or with any of the other viruses tested.

Animals↗
PubMed1985

Monoclonal precipitating antibodies to porcine immunoglobulin M.

Fusion of splenic immunocytes from a porcine IgM-immunized BALB/c mouse with SP2/0 mouse myeloma cells resulted in 231 primary hybrids. Culture fluids of the primary hybrids were screened for antibody production by enzyme-linked immunosorbent assay (ELISA) against porcine IgM and by radial immunodiffusion versus porcine serum. Culture fluids of 10 of the primary hybrids were positive in IgM-ELISA and radial immunodiffusion. Six of these primary hybrids (1A11, 1D10, 2D7, 2E2, 3B11, and 5C9) were cloned, and ascitic fluids were produced using cloned primary hybrids. The monoclonal antibodies (Mabs) in ascitic fluids were characterized as to their reactivity with porcine immunoglobulin isotypes. All six Mabs had mouse IgG1, K isotype and were mu-chain specific as they formed single precipitin lines against porcine serum and porcine IgM and no lines against porcine IgG, IgA, and fetal porcine serum in immunodiffusion and immunoelectrophoresis. In indirect ELISA, all Mabs reacted with porcine serum, porcine IgM, and mu-chains but did not react with porcine IgG, IgA, or light chains. All six Mabs were species-specific and recognized either of two antigenic regions of mu-chain. These Mabs have been successfully used to detect IgM-containing cells in tissue sections, to detect IgM in serum, and to quantitate surface membrane IgM-bearing cells in peripheral blood.

Animals↗
PubMed1985

Pathologic effects of intrauterine deposition of pseudorabies virus on the reproductive tract of swine in early pregnancy.

Pseudorabies virus was inoculated into the uterus of 15 gilts within 6 hours after natural breeding, and gilts were necropsied at postbreeding days (PBD) 3, 6, 10, 14, and 28; 3 control gilts were treated similarly, except for inoculation with pseudorabies virus and were necropsied at PBD 6, 10, and 14. Tissues were collected for virus isolation, fluorescent antibody staining, and histopathologic examination. Pseudorabies virus was isolated from the reproductive tract up to day 14. Lesions in the reproductive tract consisted of multifocal to diffuse lymphohistiocytic vaginitis and endometritis, and lymphoplasmacytic aggregates in the corpora lutea. Multiple ulcers were seen in the vagina or endometrium of several gilts at PBD 3, 6, and 10. Corpora lutea of 1 gilt were necrotic at PBD 14 and contained large numbers of inflammatory cells. Focal aggregates of lymphocytes and plasma cells were seen in vagina and endometrium of 3 gilts and in the ovary of 1 gilt at day 28.

Animals↗
PubMed1984

Evaluation of field isolates of pseudorabies (Aujeszky's disease) virus as determined by restriction endonuclease analysis and hybridization.

Sixty-seven isolates of pseudorabies virus (PRV) from 13 states were cleaved with 4 restriction endonucleases (RE), and after electrophoresis in agarose, their banding patterns were photographed and evaluated. The deoxyribonucleic acid (DNA) cleavage fragments were designated into regions specified by molecular weight ranges based on lambda phage DNA as a size marker. The 67 PRV isolates were evaluated according to the total number of cleavage fragments, by the number of fragments within designated molecular weight regions, and finally, by the migration of fragments within regions. Four of the 67 PRV isolates (all 4 from California) did not have a 4.1 to 4.6 megadalton HinfI band, but hybridization of the HinfI digests with a 32P probe made with the 4.4 megadalton band hybridized with 2 lighter fragments, 2.5 and 1.9 megadaltons, respectively. The BamHI digests of DNA from some PRV isolates with submolar fragments were hybridized with 32P probes made with fragments from the submolar region and the BamHI E fragment. Both probes hybridized to the submolar region of PRV with BamHI submolar fragments, but only to the trimolar (E, F, and G) band of PRV without submolar fragments in the 4.1 to 7.5 BamHI megadalton region. Epidemiologic evidence was obtained which indicated that a Missouri strain of PRV was transferred to an Illinois swine herd by importation of feeder pigs from Missouri. The results indicate that there are numerous genomically different PRV currently in circulation in the United States and that the combination of RE analysis and DNA hybridization offers useful epidemiologic information to evaluate the various strains.

Animals↗
PubMed1984

Biological assay of attenuated strain NADL-2 and virulent strain NADL-8 of porcine parvovirus.

Attenuated strain NADL-2 and virulent strain NADL-8 of porcine parvovirus (PPV) were titrated in vivo and in vitro under similar conditions to provide a better understanding of some of the factors involved in virulence of PPV in causing maternal reproductive failure of swine. Both strains cause fetal death when they are injected directly into fetal fluids, but only strain NADL-8 does so when administered to pregnant swine. The strains were tested for their hemagglutinating activity (HA), median cell culture infective dose (CCID50), median fetal infective dose (FID50), and median fetal lethal dose (FLD50). The FID50 and FLD50 were determined by injecting virus directly into the amniotic fluid of fetuses in utero at 44 +/- 2 days of gestation and collecting the fetuses 15 +/- 1 days later. Both strains had an HA titer of 64, suggesting that there is a similar number of virions in stock preparations. However, other measurements differed markedly. The CCID50, FID50, and FLD50 were 10(5.5), 10(3.5), and 10(0.5), respectively, for strain NADL-2, and 10(4.5), 10(7.7), and 10(6.3), respectively, for strain NADL-8. Collectively, the values indicate that more than 10,000 times as much strain NADL-2 would need to reach the conceptus transplacentally to establish infection. These observations may help to explain the different consequences of oronasal exposure of pregnant swine to these strains of PPV.

Animals↗
PubMed1984

Oronasal and intramuscular vaccination of swine with a modified live porcine parvovirus vaccine: multiplication and transmission of the vaccine virus.

An attenuated strain NADL-2 of porcine parvovirus (PPV) has been used at the 54th cell culture passage as a modified live-virus (MLV) vaccine. The present study was conducted to determine the minimum immunizing dose of MLV, the extent of MLV multiplication in swine tissues, and its transmission from swine administered MLV oronasally or intramuscularly. Immune response to MLV was dose dependent and swine responded to as little as 10(2) median cell-culture infective doses (CCID50). A 10(5) CCID50 of MLV, the largest dose given, induced the best immune response and was used in subsequent experiments. Route of MLV administration also was found to be important. The MLV replicated in tissues of swine after IM inoculation; however, viral antigen in tissues was less, as measured by immunofluorescence, and serum hemagglutination-inhibition titers for PPV were lower in MLV-inoculated swine than we have previously observed in virulent PPV-inoculated swine. In contrast, oronasal inoculation with MLV did not consistently result in infection of pigs; only 5 of 23 swine had virologic and/or serologic evidence of infection. Virus transmission studies indicated that MLV is shed in feces, but shedding occurs later than that in virulent-PPV-inoculated swine and is inconsistent. Delayed transmission of MLV was observed in contact pigs, which were seronegative at 2 weeks, but became seropositive at 4 weeks--indicating that perhaps a virus population capable of infecting pigs by oronasal route was selected by passage through the pig.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1984

Persistence of passively acquired antibodies to hemagglutinating encephalomyelitis virus in swine.

The persistence of passively acquired antibodies to hemagglutinating encephalomyelitis virus (HEV) was determined in 4 pigs in each of the litters of 10 sows. At time of delivery by the sows, the colostrum and serum samples (from the 10 sows) had hemagglutination-inhibiting antibodies to HEV. All of the pigs also had hemagglutination-inhibiting antibodies to HEV at 2 days of age. The level of circulating antibodies to HEV decreased at a nonlinear rate and persisted for about 4 to 18 (mean 10.5) weeks in the circulation of pigs. All 40 pigs were seronegative at 20 weeks of age.

Animals↗
PubMed1983

Restriction endonuclease analysis of the pseudorabies (Aujeszky's disease) virus before and after serial passage in vivo and in vitro.

The deoxyribonucleic acid (DNA) of pseudorabies virus (PRV) was examined by restriction endonuclease analysis before and after various treatments: namely 1. plaque purification of stock virus, 2. serial passage of virus in cell culture at high (H) and low (L) multiplicity of infection (MOI), and 3. serial passage of virus in swine. The objective of the study was to determine if such treatments would either select or induce virus populations with a different predominant number or location of enzyme cleavage sites. Heterogeneity of the DNA of stock virus was revealed by differences among restriction patterns of 10 plaque-purified populations. All of these populations were then relatively stable through an additional 9 plaque purifications and passages in cell culture. Without plaque purification, heterogeneity was not evident. The predominant restriction pattern of stock virus appeared unaltered by 10 serial passages in cell culture at either HMOI or LMOI, except for the appearance in the HMOI series of several minor bands. Conversely, 10 serial passages of stock virus in swine resulted in either selection or induced changes or both. Most differences were slightly altered migration rates of relatively small (less than or equal to 5 Kbp) fragments. However, after 10 passages in swine, there were also changes in the migration rates of 2 large fragments (greater than 10 Kbp) of the viral genome.

Animals↗
PubMed1982

Duration and biological half-life of passively acquired colostral antibodies to porcine parvovirus.

The duration of passive immunity and biological half-lives of passively acquired antibodies to porcine parvovirus (PPV) were determined in 4 pigs from each of 10 litters. All sows were randomly selected from a herd naturally infected with PPV. At parturition, blood and colostral samples from the 10 sows contained hemagglutination-inhibiting (HI) antibodies to PPV; the HI titers of colostrum were about 5 times higher than that of serum. The HI antibodies in serum and colostrum of sows were resistant to 2-mercaptoethanol, indicating that antibodies were of immunoglobulin G class. Pigs were allowed to suckle, and their blood samples were collected at 2 days of age and every 2 weeks thereafter. At 3 to 4 weeks of age, pigs were weaned and moved to an isolation facility. All pigs had HI antibodies to PPV at 2 days of age. Passively acquired antibodies steadily decreased from the circulation of pigs, and the rate of antibody decrease was similar in all pigs. Antibodies to PPV persisted for about 16 to 24 (mean 21.2) weeks, and all pigs were seronegative at 26 weeks of age. Pigs were susceptible to experimental infection with PPV as early as 1 week after they became seronegative. The biological half-lives of antibodies to PPV, unadjusted and adjusted for body weight gain, were determined to be approximately 19.7 and 29.0 days, respectively.

Age Factors↗
PubMed1981

Reproductive performance of gilts exposed to porcine parvovirus at 56 or 70 days of gestation.

A total of 18 pregnant gilts, which were free of antibody for porcine parvovirus (PPV), were exposed oronasally to PPV on either the 56th day (9 gilts) or 70th day (9 gilts) of the gestation to determine whether infection at these times would affect their reproductive performance. The gilts were either necropsied late in gestation or allowed to farrow, and their fetuses and pigs were tested for evidence of infection. Gilts remained clinically healthy throughout the experiment, and none farrowed prematurely. litters of 7 of 9 gilts exposed to PPV at 56 days of the gestation were infected transplacentally, and PPV caused death of fetuses in 5 of the infected litters. These litters comprised 29 dead fetuses (2 to 12/litter) and 31 live fetuses or pigs (1 to 10/litter). In addition, PPV may have been directly or indirectly responsible for an increased frequency of stillbirth and neonatal death, but the role of PPV in these conditions was difficult to assess. Litters of 6 to 9 gilts exposed to PPV at 70 days of the gestation also were infected transplacentally, but in contrast to earlier infection, PPV did not cause fetal death in these litters.

Animals↗
PubMed1980

Transplacental infection and embryonic death following maternal exposure to porcine parvovirus near the time of conception.

Each of 20 gilts (principals) from a commercial swine herd free of antibody for porcine parvovirus (PPV) was exposed intranasally and orally to PPV at the onset of gestation. The gilts were killed and necropsied 22 +/- 1 days later to determine the effect of the virus on their embryos. An equal number of gilts (controls of the same status, from the same herd, and bred to the same boars, were treated similarly except for exposure to PPV. The following data were obtained at necropsy and from subsequent laboratory tests. Principals had 223 corpora lutea (8 to 16/gilt) and 203 embryos (6 to 16/litter). Porcine parvovirus-infected embryos (1 to 9/litter) were detected in 12 (60 per cent) of the 20 litters. Of the 203 embryos of principals, 169 were alive and 34 were dead and in various stages of decomposition and resorption. Both virus and viral antigen were detected in 7 of the live embryos (1, 1, 2, and 3 in 4 litters) and in 32 of the dead embryos. With 1 exception, infected live embryos were next to infected dead littermates in the uterus suggesting the beginning of intrauterine spread of the virus. Controls had 234 corpora lutea (9 to 15/gilt) and 217 embryos (9 to 14/litter). None of their embryos were infected with PPV and all but 3 were alive.

Animals↗
PubMed1980

Porcine fetuses with pulmonary hypoplasia resulting from experimental swine influenza virus infection.

Porcine fetuses between 51 and 57 days of gestation were inoculated intraallantoically with swine influenza virus and examined 3, 7, 13, 28 and 58 days after inoculation. At 3 and 7 days, severe epithelial necrosis was seen in most bronchial buds and there was moderate epithelial necrosis in more fully differentiated major bronchi. As a result of the epithelial injury, bronchial buds did not develop further and the surrounding mesoderm failed to differentiate. By 28 days, the lungs of inoculated fetuses were about one-half the size of the normal control lungs. Microscopically, the lungs of the inoculated fetuses were composed of major bronchi surrounded by multiple islands of cartilage, medium to large arteries and a few small, incompletely developed lobules. Influenza virus was isolated most consistently and in greatest quantity from the lung, trachea and chorion of inoculated fetuses. Influenza viral antigen was shown in the epithelium of bronchial buds, bronchi and the trachea by direct fluorescent antibody staining. Hemagglutination inhibiting antibodies to influenza virus were first found in the serum of an inoculated fetus at 13 days and in the sera of all inoculated fetuses at 28 and 58 days.

Animals↗