Heinrich Stemberger

Antibody-response to three recombinant hepatitis B vaccines: comparative evaluation of multicenter travel-clinic based experience

The immunogenicity of three currently used hepatitis B vaccines was compared in an unselected study population in an every day travel clinical setting. Five hundred and eighteen vaccinees received Engerix-B (EB), 990 received Twinrix (TWX), and 366 were immunised with Gen-HB-Vax (GHB). Overall, 88.6% of the vaccinees, tested within the first 6 months after completion of the vaccination series, developed protective levels of anti-HBs (> or = 10 mIU/ml). However, GHB recipients showed significantly lower seroprotection rates (SPR) than EB and TWX recipients (79.3% vs. 87.7% vs. 92.3%, P < 0.000001). GMTs for anti-HBs, tested within 6 months after the third vaccination, showed the lowest results in the GHB group, followed by EB and TWX (142 vs. 523 vs. 1008 mIU/ml, P < 0.000001). TWX vaccinees, however, showing a higher antibody decline rate than EB recipients within the first years after completion of the full immunisation course (30% vs. 25%; P = 0.0538). This study confirms an overall good immune response to the 20 microg-dose vaccine, in the course of a regular clinical setting. The significant difference in SPRs and GMTs to the 10 microg-dose vaccine, however, may influence future immunisation practices for the elderly.

Intestinal Worm Burden and Serum Cholesterol or Lipid Concentration in a Shipibo Population (Peru)

Paired samples of stool and serum of 32 members of the Shipibo tribe resident in the rain forest of the Peruvian lowlands were tested for worm egg count and serum lipid parameters, respectively. 90% of the stool samples tested were found to contain eggs or larvae of several worm species, most commonly 3 or 4 different species. Serum lipid levels were found to be relatively low, most probably due to a low proportion of dietary fat ranging from 16-31%. Statistical analysis showed a significant inverse correlation between worm egg excretion and HDL levels which was true for hookworm, strongyloides and trichuris, but not for ascaris. The mechanisms underlying the observed association between intestinal worm load and HDL reduction are not completely understood and may include reduced HDL synthesis in the gut wall due to inflammatory and/or toxic irritation.

Tolerability of long-term malaria prophylaxis with the combination mefloquine + sulfadoxine + pyrimethamine (Fansimef®): results of a double blind field trial versus chloroquine in Nigeria

A randomized double blind study in long term malaria chemoprophylaxis was performed to compare the tolerability of Fansimef (1 tablet containing 250 mg mefloquine + 500 mg sulfadoxine + 25 mg pyrimethamine per week) with chloroquine (300 mg per week). 211 Austrian industrial workers and their families in Warri, Nigeria, participated in this study; 101 received Fansimef and 110 chloroquine for 3-18 months (mean 41 weeks). Prophylaxis was discontinued because of adverse effects in 7 volunteers in the Fansimef group (mainly insomnia, palpitations, dizziness, nausea and headache) and in 2 volunteers of the chloroquine group (headache and loss of hair in one volunteer, nausea, dizziness and vomiting in the other). Most of the adverse effects could be due to the mefloquine component. A few minor complaints of burning eyes, nausea and gastric pain were reported in both groups. Laboratory checks performed at 3-monthly intervals showed a slight, transient and clinically irrelevant (but statistically significant) increase of serum glutamic-oxalacetic transaminase and gamma-glutamyl transpeptidase at month 3 in the Fansimef group. An attack of acute Plasmodium falciparum malaria occurred in one volunteer 6 weeks after discontinuation of prophylaxis with Fansimef. Antibodies against blood stage parasites could be demonstrated by the indirect immunofluorescence test at different stages of the study, indicating that these two antimalarials are not causal prophylactic agents.

Purine metabolism in human lymphocytes

ZusammenfassungIn peripheren menschlichen Lymphozyten wurden die Aufnahme und der Stoffwechsel von Adenin, Guanin und Hypoxanthin untersucht. Die gereinigten Lymphozyten wurden mit14C-markierten Purinbasen inkubiert und anschlie\end vom Inkubationsmedium mittels rascher Filtrationstechnik getrennt. Eine bevorzugte Aufnahme einer der Purinbasen konnte nicht beobachtet werden. Die dünnschichtchromatographische Auftrennung der säurelöslichen Metabolite ergab kaum eine Bildung von Nukleosiden und anderen als den zugesetzten Purinbasen. Adenin wurde zu ca. 2/3, Guanin und Hypoxanthin hingegen zu etwa der Hälfte zu Nukleotiden aufgebaut, wobei Adenin und Guanin hauptsächlich zu ihren eigenen, Hypoxanthin jedoch zu Adeninnukiektiden metabolisiert wurde. Die Ergebnisse weisen auf die bevorzugte Bildung von Adeninnukleotiden in normalen menschlichen Lymphozyten.SummaryIn peripheral human blood lymphocytes the uptake and metabolism of adenine, guanine, and hypoxanthine was investigated. This was achieved by incubation of purified lymphocytes with14C-purine bases, separation of cells from the incubation medium by a rapid filtration technique, and subsequent separation of the acid soluble material by thin-layer chromatography. No preferential uptake for one of the purine bases was observed. In all cases only traces of14C-purine bases not added originally and labeled nucleosides could be demonstrated. Approximately 2/3 of adenine and 1/2 of guanine or hypoxanthine were converted to nucleotides. Separation of formed nucleotides showed that adenine and guanine were metabolized mainly to their corresponding nucleotides; hypoxanthine was converted to a considerable amount to adenine nucleotides and only to a small proportion into its own nucleotides. These results demonstrate the predominance of adenine nucleotide formation in normal human lymphocytes.

Guanase from Human Liver — Purification and Characterisation

Guanine aminohydrolase (E. C. 3.5.4.3.) plays an important role in the catabolism of purines, catalyzing the formation of xanthine from guanine.

Influence of Surface Hapten Density of Sheep Red Blood Cells on the Hemolytic or Blocking Activity of IgG Antibodies

The hapten density on the surface of sheep red cells, coated with benzylpenicilloic acid (BPO) was determined. This was achieved by comparison of the inhibitory capacity of the test cells with that of a standard cell preparation of known antigen density. IgG-induced hemolysis was much more affected by the recution of haptenic sites/cell than IgM-induced hemolysis. It was concluded that more than 18,000 protein islets on the sheep red cell surface bearing at least four haptenic sites were necessary for IgG-induced lysis. Target cells with 190,000 BPO groups/cell could be protected by anti-BPO-IgG against the lytic effect of simultaneously added IgM. Using target cells with 240,000 haptenic groups/cell or more a synergistic hemolytic action of IgG-and IgM-anti-BPO antibodies could be observed.

Separation and characterization of anti-benzyl-penicilloyl (BPO) antibodies. I. Biochemical and biophysical properties of anti-BPO-IgG obtained by affinity and subsequent ion-exchange chromatography

Abstract Anti-BPO antibodies were purified by means of affinity chromatography using AH-Sepharose 4B coated with covalently bound BPO groups. Specific elution was achieved by the hapten analogue BPO-ϵ-aminocaproic acid (BPO-EACA); desorption of the remaining antibody was performed thereafter by 0.1 M acetic acid. The resulting antibody fractions — hapten-eluted antibody (H-Ab) and acid eluted antibody (A-Ab), respectively — were further separated by ion-exchange chromatography which led to the appearance of 3 subfractions in the case of H-Ab (H1, H2, H3) and 2 subfractions in the case of A-Ab (A1 and A2). In liquid isoelectrofocusing an inhomegeneous pattern resulted. The bulk of antibodies focused between pH 6.5 and 7.0. The average avidity of H-Ab was found to be higher than that of A-Ab suggesting that avidity may influence the elution pattern in affinity chromatography. The hydrophobic influence of the “spacer” and/or interactions of antibodies directed against the hydrophobic regions of the BPO group may explain why a considerable part of the antibodies could be recovered from the immunosorbent only by acid elution.

Comparison between Human IgM and IgG Antibodies to Dextran, Regarding their Activities in Antibody-dependent Cellular Cytotoxicity (ADCC)

Human sera containing dextran-reactive antibodies of various immunoglobulin classes were tested for their capacity to induce ADCC against dextran-coated chicken red blood cells (CRBC). It was found that only IgG antibodies were active in ADCC, while IgM antibodies were not, thus providing further evidence that IgM antibodies do not contribute to ADCC even when human antibodies are used.

Adenine and hypoxanthine metabolism in phythohemagglutinin-stimulated and unstimulated human lymphocytes

ZusammenfassungDie Aufnahme und der Stoffwechsel von Adenin und Hypoxanthin in Phytohaemagglutinin-stimulierten und unstimulierten Blutlymphozyten wurden untersucht. Durch den Einbau von14C-markierten Purinen in die säurelösliche Fraktion sollte der 1. Schritt des Nukleinsäurestoffwechsels gemessen werden. Zwischen frisch präparierten und 48 h kultivierten Lymphozyten konnte keine bevorzugte Aufnahme von Adenin bzw. Hypoxanthin festgestellt werden. Die kultivierten Zellen metabolisierten jedoch im Vergleich zu den frisch gewonnenen Lymphozyten nur etwa 1/3 der Purine. Intrazellulär wurde 2/3 des Adenins und die Hälfte des Hypoxanthins hauptsächlich zu den Nukleotiden AMP und ADP metabolisiert. Eine 1stündige Inkubation mit PHA führte in den frischen Lymphozyten zu einem Anstieg der Adenin-bzw. Hypoxanthinaufnahme auf 191% bzw. 153% verglichen mit den Ausgangswerten. Hingegen stiegen die entsprechenden Werte während einer PHA-Stimulation von 48 h auf 158% bzw. 132% an. Obwohl die intrazelluläre Bildung der Nukleotide aus Adenin bzw. Hypoxanthin nach 1 h PHA-Stimulation auf 152% bzw. 161% anstieg, kam es zu keiner Änderung der relativen Durchflußraten der verschiedenen Stoffwechselwege. Im Gegensatz war nach 48 h Stimulation keine vermehrte Nukleotidbildung nachweisbar. Sowohl die gesteigerte Aufnahme als auch die erhöhte Nukleotidbildung nach 1 h PHA-Stimulation könnte auf geänderte Transporteigenschaften der Lymphozytenmembran hinweisen und die erste Antwort der Zelle auf den mitogenen Reiz darstellen. Dadurch könnte der gesteigerte Bedarf an niedermolekularen Substanzen für die nachfolgenden Biosynthesen gedeckt werden. Nach abgeschlossener Transformation würde kein vermehrter Bedarf bestehen und somit die Aufnahme und Metabolisierung gedrosselt werden.SummaryThe uptake and subsequent metabolism of adenine and hypoxanthine in phytohemagglutinin-stimulated and unstimulated peripheral human blood lymphocytes, freshly prepared or cultured, were studied. To investigate the initial step of nucleic acid metabolism the incorporation of14C-purines into the acid soluble material was examined. No preferential uptake of adenine or hypoxanthine was observed in freshly prepared and cultured lymphocytes during an incubation of 1 h. However, cultured cells utilized approximately 1/3 of the purines compared to freshly drawn cells. Within the cells 2/3 of adenine and 1/2 of hypoxanthine were metabolized to nucleotides (mainly AMP and ADP). Incubation of lymphocytes with PHA for 1 h produced in the freshly prepared cells an increase of adenine- and hypoxanthine-uptake to 191% and 153%, in 48 h stimulated cells to 158% and 132%. There was, however, no change in the relative rates of the metabolic routes though the intracellular concentrations of nucleotides formed increased with adenine as substrate to 152% and with hypoxanthine to 161% during a 1 h stimulation. In contrast no enhanced formation of acid soluble nucleotide formation could be observed with PHA stimulation during 48 h. The increased rates of purine uptake and metabolism apparent 1 h after addition of mitogen may be due to an altered transport mechanism at the beginning of the transformation as an adaptive response to the increased requirements for the synthetic processes soon to follow. Once the lymphocytes are transformed no demand of purines is necessary and the uptake and metabolism is switched off.

Separation and characterization of anti-benzylpenicilloyl (BPO) antibodies. II. Immunological properties of different IgG fractions

Affinity chromatography and subsequent ion-exchange chromatography of pooled anti-benzylpenicilloyl (anti-BPO) hyperimmune sera separated 5 different anti-BPO IgG fractions as described in the preceding paper. These fractions were tested for activities in passive hemagglutination (PHA), passive immune hemolysis (PIH), antibody-dependent cellular cytotoxicity (ADCC) and influence on IgM-induced hemolysis. It was found that anti-BPO IgG fractions with low avidity (dissociation constant K = 4.4--6.7 X 10(-8) moles/l) were poorly active in PHA and ADCC and had no blocking activity in IgM hemolysis. Among the highly avid antibodies (K = 0.7--3.4 X 10(-8) mole/l) no correlations were found between avidity and activities in the immunological tests. The results presented demonstrate that ion-exchange chromatography allows the separation of blocking and lytic antibodies as shown by their influence on IgM-induced complement-dependent lysis of lightly hapten-coated sheep erythrocytes.