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T T Kramer

Publications and source records attributed to T T Kramer.

13 recordsLinked to original sources
PubMed1992

A comparison of virulent and avirulent strains of Salmonella choleraesuis and their ability to invade Vero cell monolayers.

The mechanisms of invasion used by virulent and avirulent Salmonella choleraesuis were compared using a Vero cell invasion assay. Mouse virulent S. choleraesuis strain 38 and avirulent strain 9 were examined for their ability to invade and survive in Vero cells. The assay was performed by S. choleraesuis infection of the Vero cell monolayer alone and in the presence of various treatments applied to the Vero cell monolayers. Intracellular S. choleraesuis colony forming units were then counted to characterize the mechanism of bacterial uptake. Invasion was not affected by colchicine, but was significantly inhibited in the presence of cytochalasins B and D, chloroquine, and dansylcadaverine. Inhibition by the above substances suggested the importance of microfilaments and of receptor recycling in receptor mediated endocytosis. Both bacterial strains had decreased invasion in the presence of mannose and after enzymic treatment with trypsin. Mannose exposure caused a significant 48% decrease in the uptake of virulent S. choleraesuis 38 and a 28% decrease in avirulent S. choleraesuis 9. Inhibition of endosome acidification did not affect the virulent strain 38 as much as it affected avirulent strain 9. Results from these experiments suggested that Vero cell invasion by S. choleraesuis was due to host uptake by receptor mediated endocytosis, and was mediated in part by mannose-sensitive adhesins. Outer membrane proteins were extracted from the virulent and avirulent strain and compared using SDS-PAGE following surface protein labeling with 125I. Virulent S. choleraesuis 38 had a unique 35 kD protein. The outer membrane proteins of both strains were then examined by radio-immunoprecipitation and western blot using guinea pig polyclonal antisera and the 35 kD protein was again found to be unique to the virulent strain 38. Antisera against the 35 kD protein significantly inhibited invasion of Vero cells by S. choleraesuis strain 38.

Actin Cytoskeleton↗
PubMed1992

Characterization of a Salmonella choleraesuis isolate after repeated neutrophil exposure.

Salmonella choleraesuis strain 38 (glycerol-positive fermentation) was repeatedly exposed to porcine neutrophils in an attempt to mimic in vivo conditions of the host immune system. After phagocytosis, viable intracellular S choleraesuis were isolated and the process was repeated at least 5 times. A fifth-passage strain-38 neutrophil-adapted clone, 38PMNa-5X, was isolated, and was compared with the parent wild-type strain 38 for changes. Strain 38PMNa-5X had increased resistance to killing by hydrogen peroxide and phagocyte killing by porcine neutrophils, as measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction. Strain 38PMNa-5X was less invasive than the parent strain on Vero cell monolayers, and had been cured of a 50-kb plasmid. The 50-kb plasmid was marked with bacteriophage mini-Mu (kanamycin resistant) and was reinserted into strain 38PMNa-5X. Strain 38PMNa-5X was avirulent in mice, but the isolates with reinserted plasmids had intermediate resistance to neutrophil and hydrogen peroxide killing and had restored invasiveness and mouse virulence. Differences in complement sensitivity and enzymatic activity were not observed between the strains.

Animals↗
PubMed1992

In vivo isolation of Salmonella choleraesuis from porcine neutrophils.

Seventy-five pigs from 4 facilities were examined for Salmonella choleraesuis by use of bacteriologic culture of feces, blood, WBC (buffy coat), mononuclear leukocytes, and neutrophils. The organism was isolated from 0 of 75 fecal samples, compared with isolation from 39 of 75 purified neutrophil preparations. Of the pigs that did not have Salmonella isolated from feces or blood, but had S choleraesuis isolated from neutrophils, 6 were further examined. These pigs from 2 groups again had culture performed at least 3 successive times to test for repeatability and to determine optimal number of neutrophils required for Salmonella isolation. These same pigs were euthanatized and necropsied. Nineteen tissue specimens from each pig were obtained for culture, but S choleraesuis was isolated only from neutrophil samples. Results indicate that neutrophils may contribute to the carrier state in pigs and should be cultured when attempting to identify S choleraesuis carrier swine.

Animals↗
PubMed1992

Safety and efficacy of an attenuated strain of Salmonella choleraesuis for vaccination of swine.

The purpose of this study was to determine the safety and efficacy of a live Salmonella choleraesuis immunizing strain, obtained by repeated ingestion and recovery through porcine neutrophils. The strain was tested in mice and in pigs. The vaccine was safe and effective in controlled experimental trials, using clinical, pathologic, and microbiologic criteria. Vaccinated pigs were able to maintain normal weight gains during the 4-week observation period following challenge inoculation with a high dose of a virulent strain.

Animals↗
PubMed1989

Porcine neutrophil function in the presence of virulent and avirulent Salmonella choleraesuis.

Porcine polymorphonuclear leukocytes (PMNLs) may be activated by bacteria to begin phagocytosis followed by oxidative and non-oxidative mechanisms of killing. The purpose of this study was to identify differences between virulent and avirulent Salmonella choleraesuis (S. choleraesuis) strains, 38 and 9 respectively, in their interactions with porcine PMNLs using five different assays. (1) Staphylococcus aureus (S. aureus) ingestion was determined by exposure of porcine PMNLs to a mixture of S. choleraesuis and 125I labeled S. aureus. There was a 2.98% and 22.20% decrease in S. aureus ingestion by mouse-avirulent S. choleraesuis 9 and mouse-virulent S. choleraesuis 38 respectively. (2) Iodination of proteins was done by exposing zymosan stimulated porcine PMNLs to S. choleraesuis in the presence of 125I and measuring its incorporation into porcine PMNL proteins. This assay indicated a 73.7% and 74.7% decrease in iodination by S. choleraesuis 9 and S. choleraesuis 38, respectively. (3) Cytochrome c reduction was performed by using porcine PMNLs, zymosan, and S. choleraesuis to determine the bacterial effect on superoxide anion production. S. choleraesuis 9 and S. choleraesuis 38 inhibited superoxide anion production by 78.0% and 92.6%, respectively. (4) Lactoferrin release from porcine PMNLs was measured by an ELISA using the supernatant from the cytochrome c assay. Results indicate a 52.0% and 61.0% increase in lactoferrin release by S. choleraesuis 9 and 38 respectively. (5) The bactericidal assay was performed by counting cfus of S. choleraesuis after preliminary incubation with porcine PMNLs, followed by killing of extracellular S. choleraesuis and lysis of porcine PMNLs. Survival of S. choleraesuis 9 and E. coli (control) were 7.50% and 1.37%, respectively, in contrast to 52.62% survival of the virulent S. choleraesuis 38. These results indicate that both strains inhibited protein iodination and caused a slight increase in lactoferrin release, but the virulent S. choleraesuis 38 inhibited S. aureus ingestion, cytochrome c reduction, and survived porcine PMNL killing more effectively than the avirulent S. choleraesuis 9.

Acridine Orange↗
PubMed1978

Cell-mediated immune response after Brucella abortus S19 vaccination.

Cell-mediated immunity to Brucella abortus S19 vaccine was measured in young heifers by the microassay for stimulation of protein synthesis (SPS) with [3H]leucine and the skin test for delayed hypersensitivity. Brucella melitensis protein allergen and a crude B abortus S19-soluble antigen were compared in the SPS test. The SPS test was negative in 5 unvaccinated heifers and strongly positive in 3 twice-vaccinated steers. However, the SPS test was positive only in 13 of 30 S19-vaccinated heifers and the delayed hypersensitivity in 9 of 29 S19-vaccinated heifers. The 2 tests gave good agreement. Vaccination-induced residual antibody titers were partly correlated with the outcome of the tests used to measure cell-mediated immunity.

Animals↗
PubMed1978

Cell-mediated and humoral immune responses of cattle to Brucella abortus, Mycobacterium bovis, and tetanus toxoid: evaluation of immunization and assay techniques.

A concentration of 2.5 X 10(-5) M 2-mercaptoethanol (2-ME) added to the medium in lymphocyte blastogenesis assays increased both the uptake of [3H]thymidine in unstimulated lymphocyte cultures and the probability of detecting antigen-sensitized cattle. The use of 2-ME did not cause lymphocytes from unsensitized cattle to react positively in blastogenesis assays. A crude brucella lysate prepared from Brucella abortus strain 19 was compared with a well-characterized brucella protein allergen prepared from B melitensis and was found to be equally suitable for use in blastogenesis assays. Cell-mediated immunity was produced most effectively in 4-month-old calves by tetanus toxoid, then by Mycobacterium bovis, and least effectively by B abortus.

Animals↗
PubMed1977

Antigenicity of bdellovibrios.

Antigenic relationships between 12 locally isolated bdellovibrios and 3 established reference strains (109D, 6-5-S, and UKi2) were investigated. Antigenicity of the strains was examined by use of the micro-complement fixation test, the serum and complement bactericidal test, and the immunodiffusion test. Antisera were prepared against one of the local strains (MS7) and against one of the established reference strains (UKi2). The complement fixation titers suggest a close relationship among all strains. Immunodiffusion tests produced lines of identity between the homologous strain MS7 and all other strains. It is suggested on the basis of these results that bdellovibrio may possess a common antigen.

Antigens, Bacterial↗
PubMed1977

Bdellovibrio and the intestinal flora of vertebrates.

Bdellovibrio strain MS7 force-fed to fish and frogs via an intragastric tube did not become an integral component of the intestinal microflora. Strain MS7 fed to mice in drinking water was not recovered from the intestinal tract of mice. However, in vitro, the organism multiplied in intestinal contents of frogs and mice. Bdellovibrio inoculated into rabbit ileal loops was greatly reduced in number within 24 h. It was concluded that strains MS7 could be considered nonpathogenic to animals, at least when introduced into the digestive tract, and that it is not feasible at the present time to lyse pathogenic, gram-negative bacteria in the alimentary tract with Bdellovibrio.

Animals↗