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Biomedical subjects

J T Ulrich

Publications and source records attributed to J T Ulrich.

35 records · Page 2Linked to original sources
PubMed1991

Cross-neutralizing antibodies in rabbits immunized with HIV-1 gp160 purified from simian cells infected with a recombinant vaccinia virus.

A recombinant vaccinia virus in which the transcription of the human immunodeficiency virus type 1 (BRU isolate) env gene is driven by the 11K late vaccinia promoter yields about 10-fold higher amounts of gp160 env protein upon infection of monkey cells than does a recombinant in which gp160 is expressed using the 7.5K early-late promoter. The gp160 was purified from detergent lysates of infected cells by lentil lectin affinity chromatography followed by immunoaffinity chromatography, and was obtained in yields of 1-2 mg/10(9) cells of material estimated to be about 70% pure. Pairs of rabbits were immunized with purified gp160 using either one of five different adjuvants or an immunostimulating complex. In all cases a substantial humoral immune response was obtained after boosting, including an activity that neutralized the homologous (BRU) isolate of HIV-1. In some cases, this activity also neutralized two distantly related isolates, SF2 and MN.

Animals↗
PubMed1991

Vaccination of calves with a modified bacterin or oil-in-water emulsion containing alkali-detoxified Salmonella typhimurium lipopolysaccharide.

Twenty-six clinically normal colostrum-fed dairy calves were allotted to 5 groups. Calves of groups 1 and 2 served as nonvaccinated controls and were challenge-exposed with variable numbers of organisms. Group-3 calves were vaccinated SC with a modified Salmonella typhimurium bacterin. The bacterin was composed of killed acid-hydrolyzed S typhimurium G30/C21 (Re-mutant) whole cells coated with alkali-hydrolyzed S typhimurium LT-2 lipopolysaccharide, as antigen, and monophosphoryl lipid A, as adjuvant. Calves of groups 4 and 5 were vaccinated with a 2% mineral oil-in-water emulsion containing lipopolysaccharide as antigen and monophosphoryl lipid A and trehalose 6-6'-dimycolate as adjuvants. Calves of groups 3-5 were vaccinated at 2 weeks of age and again at 4 or 6 weeks of age. Adverse reactions were not observed after vaccination. Calves were challenge-exposed orally at 6 or 8 weeks of age with 1.5 X 10(11) (groups 1 and 4), or 3.0 X 10(11) (groups 2, 3, and 5) colony-forming units of S typhimurium UCD 108-11. Mortality after challenge exposure was 2 of 5 group-1 calves; 4 of 5 group-2 calves; 5 of 6 group-3 calves; 1 of 5 group-4 calves; and 4 of 5 group-5 calves. Statistical difference between calves of similarly challenge-exposed groups was not evident, indicating failure of either vaccine to protect calves of this age from oral challenge exposure with virulent S typhimurium.

Animals↗
PubMed1990

Enrichment of suppressor T cells by means of binding to monophosphoryl lipid A.

The binding and elution of spleen cells from plastic dishes coated with monophosphoryl lipid A (MPL) resulted in a greater than 1,000-fold enrichment of antigen-specific suppressor T-cell (TS) activity when spleen cells from mice 18 to 24 h after exposure to a low dose of type III pneumonococcal polysaccharide (SSS-III) were used. The removal of MPL-adherent TS cells resulted in an increase in the degree of amplifier T-cell (TA) activity present in the remaining MPL-nonadherent cell fraction; however, both TS and TA activities were found in the MPL-adherent cell fraction when spleen cells from mice 4 days after immunization with an optimal dose of SSS-III were examined. These findings, as well as others, suggest that both TS and TA, once activated, acquire a cell surface receptor that enables them to bind to MPL. Because of differences in the kinetics for the activation of TS and TA during the course of the antibody response and the fact that TS, but not TA, activity appears as early as 18 to 24 h after exposure to SSS-III, it is possible to use this experimental approach to obtain cell suspensions greatly enriched in TS activity.

Animals↗
PubMed1989

Trehalose dimycolate enhances resistance to infection in neutropenic animals.

Bacterial infections are lethal complications of neutropenia, and antibiotics alone are inadequate therapy for these infections. Irradiated mice become severely neutropenic and remain susceptible to infection for 2 to 3 weeks, depending on the dose and quality of radiation. Some bacterial cell wall derivatives stimulate nonspecific host defense mechanisms against a variety of microbes which might cause postirradiation infection. In this study we determined if the cell wall glycolipid trehalose dimycolate (TDM), derived from Mycobacterium phlei, or a synthetic preparation of TDM was able to (i) enhance survival in mice when given before or after lethal doses of 60Co radiation and (ii) increase nonspecific resistance to postirradiation infection. Treatment with TDM oil-in-water emulsions and with synthetic TDM significantly enhanced survival before and after lethal doses of 60Co irradiation. This result correlated with the ability of TDM to reduce the translocation of intestinal bacteria and to stimulate hematopoiesis. With respect to nonspecific resistance to infection, TDM injected 1 h after sublethal irradiation increased resistance to a lethal Klebsiella pneumoniae challenge (10 50% lethal doses of K. pneumoniae in 30 days [LD50/30]) 4 or 14 days later. Increasing the dose of K. pneumoniae to 5,000 LD50/30 on day 4 overwhelmed the ability of TDM-treated mice to overcome infection. However, TDM treatment 1 h postirradiation combined with ceftriaxone antibiotic therapy (days 5 through 14) enhanced survival, even when the higher dose of bacteria (5,000 LD50/30) was used. These results indicate that in irradiated mice, TDM can be used to enhance survival and, as a potent stimulant of nonspecific resistance to infection in neutropenic mice, can act synergistically with antibiotic therapy to reduce sepsis and mortality.

Adjuvants, Immunologic↗
PubMed1986

Monoclonal antibodies to bovine UDP-galactosyltransferase. Characterization, cross-reactivity, and utilization as structural probes.

A series of mouse monoclonal antibodies has been developed against a soluble form of bovine UDP-galactose:N-acetylglucosamine galactosyltransferase purified to apparent chemical homogeneity by a combination of affinity and immunoadsorption chromatography. The purified enzyme consists of two molecular mass variants of 42 and 48 kDa. Individual monoclonal antibodies were selected for by their ability to recognize immobilized affinity-purified galactosyltransferase and were not reactive against bovine alpha-lactalbumin and bovine immunoglobulins. Based on competitive binding assays and Western blot analysis with either galactosyltransferase or lactose synthetase (covalently cross-linked alpha-lactalbumin galactosyltransferase), these monoclonal antibodies can be subdivided into four groups. Group A (3 clones) recognize an epitope at or near the alpha-lactalbumin binding site. In addition, this group is cross-reactive with soluble galactosyltransferase from human milk and pleural effusion. Group B (6 clones) and D (1 clone) appear to recognize two different epitopes on the 6-kDa fragment which is released when the 48-kDa galactosyltransferase polypeptide is converted to the 42-kDa form, apparently by proteolysis. Groups A and C (1 clone) recognize epitopes found on both the 48- and 42-kDa polypeptide. Interestingly, immunofluorescence studies indicate that only two monoclonal antibody groups (C and D) are able to decorate membrane-bound galactosyltransferase (Golgi-associated) in formalin-fixed, methanol-, or detergent-permeabilized cells. Thus, these groups of monoclonal antibodies appear to identify four separate structural/functional domains on soluble galactosyltransferase, two of which are not readily accessible for binding in situ.

Animals↗
PubMed1984

Erythromycin uptake and accumulation by human polymorphonuclear leukocytes and efficacy of erythromycin in killing ingested Legionella pneumophila.

Studies were undertaken to demonstrate the efficacy of erythromycin in killing Legionella pneumophila organisms that have been ingested by human polymorphonuclear leukocytes. With use of an electron microscope-autoradiography method in conjunction with an antibiotic-uptake assay, it was shown that [3H]-labeled erythromycin A base penetrated into the cytoplasm of human polymorphonuclear leukocytes in concentrations up to 24 times higher than the extracellular drug level. Similar studies using [14C]benzyl penicillin revealed that this antibiotic penetrated human polymorphonuclear leukocytes very poorly. Removal of erythromycin from the extracellular environment resulted in rapid leakage of radioactivity from the cells; an assay for bioactivity showed that this material was unaltered drug. Human polymorphonuclear leukocytes were permitted to ingest L. pneumophila and were then treated with erythromycin A base. The erythromycin killed the ingested legionellae, as evidenced by bacterial plate counts and morphological destruction of ingested organisms. These data clearly demonstrate the efficacy of erythromycin in killing susceptible intracellular pathogens.

Erythromycin↗
PubMed1983

Enzyme-Linked Immunosorbent Assay for Quantitative Detection of Bacillus thuringiensis Crystal Protein.

Accurate measurement of the toxic protein crystal produced during deep-tank fermentation of Bacillus thuringiensis is critical for optimum process yield. The currently accepted method is a bioassay that requires more time to generate data than to complete the fermentation itself. A noncompetitive enzyme-linked immunosorbent assay has been developed with purified B. thuringiensis crystals to generate rabbit antiserum. This technique gives a quantitative crystal protein value with a colorimetric endpoint for either liquids or powders within 4 h of sampling. Reproducibility of this enzyme-linked immunosorbent assay satisfies criteria for use in a commercial process.

Journal Article↗
PubMed1977

Development of a localized hemolysis-in-gel assay for Vi antigen: characterization of the Vi-specific PFC response of nude and normal mice.

An assay to detect specific plaque-forming cells (PFC) to Vi antigen (Vi) was developed and the optimal conditions for sensitization of sheep erythrocytes (SE) and plaque development were determined. Using PFC and passive hemagglutination (PHA) assays, Vi-specific immune responses of athymic (nude) and normal mice were characterized. Vi was found to elicit only IgM PFC. No discernable secondary response was detected following a second injection of antigen. Nude and normal mice responded in a quantitatively similar manner to all doses of Vi tested and responded similarly on varying days following immunization. Also, both nude and normal mice produced the greatest number of Vi-specific PFC 4 days following immunization with an optimally immunogenic dose of Vi (1.0 microng/mouse). These results indicate that functional thymus-derived cells are not necessary to elicit an immune response against Vi antigen.

Animals↗
PubMed1972

Mode of action of oxathiin systemic fungicides. V. Effect on electron transport system of Ustilago maydis and Saccharomyces cerevisiae.

The systemic fungicide carboxin (5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide) at 100 mum inhibited succinate cytochrome c reductase in mitochondria from Ustilago maydis and Saccharomyces cerevisiae. It did not have any effect on reduced nicotinamide adenine dinucleotide (NADH) cytochrome c reductase. Succinate coenzyme Q reductase was also inhibited, but NADH coenzyme Q reductase was not. When dichlorophenolindophenol (DCIP) was used as the terminal acceptor of electrons from the oxidation of succinate, carboxin was very effective in inhibiting succinate-DCIP reductase. Carboxin was inhibitory to succinic dehydrogenase assayed with phenazine methosulfate plus DCIP when intact mitochondria were used as the enzyme source but not when solubilized enzyme was used. The main site of action of carboxin, therefore, appears to lie between succinate and coenzyme Q. The dioxide analogue of carboxin was also effective in inhibiting succinate-cytochrome c reductase, succinate-coenzyme Q reductase, or succinate-DCIP reductase, whereas the monoxide analogue was less effective in inhibiting these enzymes.

Anilides↗
PubMed1972

Induction and characterization of -galactosidase in an extreme thermophile.

A thermostable beta-galactosidase (EC 3.2.1.23; beta-dgalactoside galactohydrolase) was found to be inducible in an extreme thermophile resembling Thermus aquaticus. Enzyme induction was achieved by the addition of lactose, galactose, or the alpha-galactoside, melibiose, to growing cultures. The addition of glucose to induced cultures had a repressive effect on further enzyme synthesis. The enzyme was purified 78-fold, and the optimum temperature and pH for activity were determined to be 80 C and pH 5.0, respectively. The enzyme was activated by both manganese and ferrous iron. Sulfhydryl activation and thermal stabilization indicate that the thermophilic beta-galactosidase is a sulfhydryl enzyme. Kinetic determinations at 80 C established a K(m) of 2.0 x 10(-3)m for the chromogenic substrate o-nitrophenyl beta-d-galactopyranoside (ONPG) and a K(1) of 7.5 x 10(-3)m for lactose. The Arrhenius energy of activation (for the hydrolysis of ONPG) was calculated to be 13.7 kcal/mole. A molecular weight of 5.7 x 10(5) daltons was estimated by elution of the enzyme from Sephadex 4B.

Acetone↗
PubMedDate not supplied

Preparation and characterization of biologically active 6'-O-(6-aminocaproyl)-4'-O-monophosphoryl lipid A and its conjugated derivative.

N-tert-butyloxycarbonyl (t-Boc) protected 6-aminocaproic (Cap) anhydride was reacted with unprotected hexaacyl-4'-O-monophosphoryl lipid A (MLA) obtained from the lipopolysaccharide of Escherichia coli J5 to yield t-Boc-Cap-MLA. After a column purification step, the t-Boc group was removed by incubating the sample at low temperature in the presence of acid to yield Cap-MLA. This product was analyzed by californium plasma desorption mass spectrometry (PDMS). Purified t-Boc-Cap-MLA was further fractionated by reverse-phase high-performance liquid chromatography as its methyl ester and characterized by laser desorption mass spectrometry, PDMS, and proton nuclear magnetic resonance spectroscopy. These analyses revealed that the Cap group was selectively introduced into the 6'-position of MLA. To demonstrate that Cap-MLA can be conjugated to other compounds, it was reacted with biotin-Cap N-hydroxysuccinimide ester to yield biotin-(Cap)2-MLA. Analysis of this product by PDMS confirmed its expected molecular weight of 2171 and showed the presence of fragments containing the biotin and Cap groups. Monoclonal antibodies and streptavidin were used to show the presence of both lipid A and biotin in this conjugated product. These two novel lipid A derivatives were then tested for their bioactivities. Although both Cap-MLA and biotin-(Cap)2-MLA showed mitogenic activity using murine splenocytes, they were about 4-8 times less active than MLA at 20 micrograms/mL or less and only one-half as active at 100 micrograms/mL.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗