Gw Welling

THE INFLUENCE OF PH AND IONIC-STRENGTH ON THE COATING OF PEPTIDES OF HERPES-SIMPLEX VIRUS TYPE-1 IN AN ENZYME-LINKED IMMUNOSORBENT-ASSAY

Rabbits were immunized with synthetic peptides of herpes simplex virus type 1 glycoproteins, coupled to a carrier protein with glutaraldehyde. Antibodies directed against the peptides were determined in an enzyme-linked immunosorbent assay (ELISA). Either free peptides or peptides coupled with glutaraldehyde to another carrier protein than the one used for immunization were used as the coating antigen. When conjugated peptides were used as the coat, it was necessary in some instances to correct the antibody titers for a substantial amount of antibody activity against glutaraldehyde. When free peptides were used, optimal coating conditions with regard to pH and ionic strength had to be determined, since some peptides failed to coat under standard conditions, at pH 9.6. The results show that some peptides needed stringent pH conditions while others could be coated in a broad pH range. The addition of 0.6 M NaCl had a favorable effect on peptide coating.

THE INFLUENCE OF DIFFERENT ADJUVANTS ON THE IMMUNE-RESPONSE TO A SYNTHETIC PEPTIDE COMPRISING AMINO-ACID RESIDUES 9-21 OF HERPES-SIMPLEX VIRUS TYPE-1 GLYCOPROTEIN-D

The immuno-modulating properties of different adjuvant systems on the murine humoral and cellular immune response to a synthetic peptide comprising amino acid residues 9-21 of glycoprotein D of herpes simplex virus type 1 (HSV-1) were investigated. For immunization, the peptide was conjugated to ovalbumin or bovine serum albumin by glutaraldehyde and the adjuvants used in this study were Freunds complete adjuvant (FCA), aluminium hydroxide, the Ribi adjuvant system (RAS) and two non-ionic block polymer surfactants, viz. L101 and 31R1, in oil in water emulsions. High anti-peptide antibody titers were obtained after immunization with FCA, aluminium hydroxide, RAS and L101. All adjuvants, except RAS, stimulated the induction of delayed type hypersensitivity obtained after immunization with peptide 9-21 coupled to ovalbumin and elicited by injection of purified HSV-1 virions in the footpad. Challenge with a lethal dose of HSV-1 showed that mice immunized with peptide 9-21 coupled to ovalbumin in combination with FCA, RAS and L101, respectively, were significantly protected. Although immunization with peptide 9-21 coupled to ovalbumin combined with aluminium hydroxide stimulated induction of delayed type hypersensitivity, no significant protective immunity against the challenge was generated.

THE SCREENING OF 4 AMINOGLYCOSIDES IN THE SELECTIVE DECONTAMINATION OF THE DIGESTIVE-TRACT IN MICE

SummaryThe suppressive effect of amikacin, gentamicin, tobramycin and paromomycin on the aerobic endogenous flora and on the colonization resistance of the digestive tract was tested by administering one of the antibiotics orally at five different dose levels. At a certain dose level, all antibiotics suppressed the endogenousEnterobacteriaceae species. Amikacin was particularly effective in this respect. Low doses of amikacin rapidly destroyed the colonization resistance. This resistance only remained unaffected in animals treated with tobramycin in doses that were still adequate to completely suppress the endogenousEnterobacteriaceae species. We concluded that of all the antibiotics tested in this study, only tobramycin may have a future in (clinical) application for the selective decontamination of the digestive tract. Selective decontamination can be considered an effective method for infection prevention in leukopenic patients.ZusammenfassungDie Unterdrückung der aeroben endogenen Flora und Verminderung der Kolonisationsresistenz des Verdauungstraktes durch orale Behandlung mit Amikacin, Gentamicin, Tobramycin und Paromomycin in fünf verschiedenen Dosen wurde bei Mäusen geprüft. Von einer bestimmten Dosishöhe an zeigten alle untersuchten Antibiotika eine hemmende Wirkung auf die endogenenEnterobacteriaceae-Spezies; die Empfindlichkeit gegenüber Amikacin war besonders hoch. Amikacin zerstörte bereits in niedrigen Dosen rasch die Kolonisationsresistenz. Bei Anwendung von Antibiotikadosen, die zur vollkommenen Unterdrückung derEnterobacteriaceae-Spezies ausreichten, blieb nur bei den mit Tobramycin behandelten Tieren die Kolonisationsresistenz unbeeinträchtigt. Von den geprüften Substanzen dürfte nach den Ergebnissen dieser Untersuchung nur Tobramycin zur selektiven Dekontamination des Verdauungstraktes beim Patienten eine Zukunft haben. Grundsätzlich kann die selektive Dekontamination als wirksame Methode zur Infektionsverhütung bei leukopenischen Patienten angesehen werden.

Synthetic antibody fragment as ligand in immunoaffinity chromatography

The possibility that a fragment of an antibody molecule may interact with a protein antigen was tested by studying the binding properties of a thirteen-residue synthetic peptide with an amino acid sequence similar to part of a hypervariable segment of a monoclonal antibody directed against lysozyme. Affinity adsorbents were prepared with this peptide and with non-related peptides as ligand. Non-specific interactions could be abolished by washing the column with 0.05 M sodium thiocyanate in 20 mM tris-HCl (pH 7.4). Lysozyme was only bound to the antilysozyme adsorbent and could be eluted with 1 M sodium thiocyanate. The results show that immunoaffinity chromatography with synthetic peptide ligands which mimic the antigen-binding site may be a useful tool in the selective purification of proteins.

THE EFFECT OF CEFTRIAXONE ON THE ANAEROBIC BACTERIAL-FLORA AND THE BACTERIAL ENZYMATIC-ACTIVITY IN THE INTESTINAL-TRACT

SummaryThe normal flora of the intestinal tract, mainly consisting of anaerobic bacteria, protects the host against colonization by pathogenic microorganisms. Antimicrobial treatment with ceftriaxone may influence the colonic microflora and as a consequence, the protective effect. Ten healthy volunteers received 1 g of ceftriaxone intramuscularly for five days. This resulted in a significant decrease (p<0.05) of the mean cultural counts (± SEM) of total anaerobes from 10.67 (0.11) (prior to treatment) to 9.02 (0.45) and 8.97 (0.46) at days 3 and 5, respectively (during treatment). After treatment (days 10 and 15–19), the cultural counts of anaerobes returned to 10.17 (0.16) and 10.44 (0.18), respectively. Bacterial enzymes may serve as an indicator of protective microflora. β- aspartylpeptidase and deoxycholate hydrolase activity was determined in faecal supernatants of the volunteers and compared with anaerobic culturing. Both enzymatic activities show a significant correlation with the total number of anaerobes present at day 3 of ceftriaxone treatment. At day 5 and 8 only β-aspartylpeptidase showed significant correlations with cultural counts of total anaerobes,Bacteroides spp. or bifidobacteria. At day 15 to 19 (ten to 14 days after treatment) β-aspartylpeptidase showed only a significant correlation with the number ofBacteroides spp. This indicates that changes in the indigenous bacterial flora during and shortly after treatment with ceftriaxone can be monitored by determination of β-aspartylpeptidase. Recovery of the intestinal flora is difficult to assess in this manner.ZusammenfassungDie normale Flora des Intestinaltraktes besteht vorweigend aus anaeroben Bakterien und schützt den Wirt gegen eine Kolonisation durch pathogene Mikroorganismen. Eine antimikrobielle Therapie mit Ceftriaxon kann die Mikroflora des Dickdarms beeinträchtigen und damit auch deren protektiven Effekt. Zehn gesunde Probanden erhielten fünf Tage lang 1 g Ceftriaxon intramuskulär appliziert. Dies führte zu einer signifikanten Abnahme der mittleren Koloniebildnerzahlen von 10,67 (SEM ± 0,11) vor Applikation auf 9,02 (± 0,45) nach drei und auf 8,97 (± 0,46) nach fünf Tagen (p<0,05). Nach zehn und 15 bis 19 Tagen im Anschluß an die Antibiotikagabe kehrten die Anaerobier-Koloniebildnerzahlen auf 10,17 (± 0,16) bzw. 10,44 (± 0,18) zurück. Bakterienenzyme können als Indikator für die protektive Mikroflora dienen. In Überständen von Stuhlproben der Probanden wurden β-Aspartylpeptidase und Desoxycholat-Hydrolase bestimmt und mit den Anaerobier-Kulturen verglichen. Zwischen den Aktivitäten beider Enzyme und der am Tag 3 gemessenen Anaerobier-Gesamtzahl fand sich eine signifikante Korrelation. Am Tag 5 und Tag 8 zeigte nur die β-Aspartylpeptidase eine signifikante Korrelation mit den Gesamt-Kolonie-bildnerzahlen der Anaerobier sowie mit den Zahlen vonBacteroides spp. oder Bifidobakterien. An den Tagen 15 bis 19 (zehn bis 14 Tage nach Antibiotikagabe) bestand nur zwischen der Zahl vonBacteroides spp. und β-Aspartylpeptidase eine signifikante Korrelation. Nach Behandlung mit Ceftriaxon lassen sich folglich Veränderungen der bakteriellen Flora kurzfristig durch Bestimmung der β-Aspartylpeptidase erfassen, weniger gut aber die Erholung der Darmflora.

T cell responses to synthetic peptides of herpes simplex virus type 1 glycoprotein D in naturally infected individuals

SummaryTo locate T cell determinants of glycoprotein D (gD) of herpes simplex virus type 1 (HSV-1), proliferation assays of lymphocytes obtained from 10 healthy HSV-seropositive individuals were performed using 34 overlapping gD peptides as antigens. Despite large differences between individual responses to the peptides both in number of stimulating peptides and gD regions, three regions (1–54, 110–214, and 290–314) induced a response in 50% or more of the HSV-seropositives. T cells were less frequently stimulated by peptides of region 210–294. No correlation was found between serological data and proliferative responses to the peptides. The diversity in T cell response to the peptides suggests a lack of immunodominance, implying that a single peptide/region of gD, or a combination of peptides, will not be sufficient to serve as a basis for a future HSV-1 vaccine.

Immunologic comparison of pancreatic ribonucleases

Abstract Ouchterlony double immunodiffusion and micro-complement fixation were used in cross-reactivity studies with 9 pancreatic ribonucleases differing 3–28% in amino acid sequence and rabbit antisera to cow, gnu, reindeer and whale ribonuclease. Generally a correlation was observed between the extent of cross-reactivity and amino acid sequence resemblance. The antiserum against whale ribonuclease however, reacted to a larger degree with several antigens than expected from the amino acid sequence difference. Dromedary ribonuclease, which differs at 26% of the positions, showed the highest cross-reaction. By comparing the antigenic reactivities and the differences in sequence, an attempt was made to localize antigenically relevant regions.

COMPARISON OF REVERSED-PHASE COLUMN MATERIALS FOR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF PROTEINS

Nine reversed-phase materials with various bonded phases from different suppliers were studied for the separation of hydrophilic proteins with two solvent systems. Protein retention, resolution and recovery were not correlated with the nature of the hydrocarbonaceous ligand. Peak volumes increased with molecular weight, which led to broad, irregular peaks for the larger proteins on some columns. Four columns that performed equally well were selected for the purification of hydrophobic Sendai virus membrane proteins. In this case, more distinct differences were found between columns. Recovery of the membrane proteins strongly depended on the combination of column and solvent systems.

Immunological properties of multiple repeats of a linear epitope of herpes simplex virus type 1 glycoprotein D

Several peptides containing the amino acid sequence 9-21 of glycoprotein D of herpes simplex virus type 1 (HSV-1) were synthesized and investigated for reactivity with monoclonal antibody LP14 in a competition enzyme-linked immunosorbent assay (ELISA). Peptides containing two or four repeats of sequence 9-21 reacted at least one order of magnitude better with LP14 than with the monomeric form of sequence 9-21. Dimers in which one of the repeats of one or more essential residues were absent did not show this increased reactivity. Antisera obtained from rabbits immunized with a peptide containing two repeats of sequence 9-21 coupled to bovine serum albumin showed high antipeptide antibody titers with this peptide and were able to neutralize virus infectivity in vitro. Sera obtained from rabbits immunized with the free dimer could not neutralize virus infectivity.

Comparison of non-ionic detergents for extraction and ion-exchange high-performance liquid chromatography of Sendai virus integral membrane proteins

The integral membrane proteins of Sendai virus haemagglutinin-neuraminidase (HN) and fusion protein (F) were extracted from purified virions with 2% of a non-ionic detergent, i.e., polyoxyethylene alkyl ethers varying by 8-14 hydrocarbon units in the alkyl chain and by 4-8 ethylene glycol units in the oxyethylene chain. Triton X-100 and octyl glucoside were included as reference detergents. The hydrophile-lipophile balance (HLB) and the critical micelle concentration (CMC) of the detergents were determined. A decrease in length of the oxyethylate by 8-5 ethylene glycol units and an increase in the alkylate by 8-12 hydrocarbon units resulted in higher yields of extracted proteins. The highest yields were obtained for C12E5 with an HLB of 11.7. Yields of extracted protein could be correlated with the HLB values of the polyoxyethylene alkyl ethers. The structural integrity of HN and F was not affected during extraction by either detergent as measured by their reactivity with monoclonal antibodies directed against native HN and F. Extracts were subjected to anion-exchange high-performance liquid chromatography (HPLC) on a Mono Q column in the presence of 0.1% of the detergent used for extraction. Eluate fractions were analysed by sodium dodecyl polyacrylamide gel electrophoresis and recoveries of HN and F protein were determined by size-exclusion HPLC. The immunological activity of HN and F was tested in an enzyme-linked immunosorbent assay. The highest recoveries of HN and F (80%) were obtained with C10E5 in the elution buffer. HN and F were partially purified and the immunological activity was well preserved.