PubMed Health⌕ Search

Biomedical subjects

E Liehl

Publications and source records attributed to E Liehl.

At least 55 records · Page 3Linked to original sources
PubMed1983

Entrapment of animal cells for production of monoclonal antibodies and other biomolecules.

Animal cell technology is attracting considerable interest because of the capacity of animal cell cultures to synthesize or transform complex compounds such as virus vaccines, immunochemicals, hormones or enzymes. For the growth of surface-dependent cells, microcarrier technology is gaining importance. Here, we have attempted to immobilize surface-independent cells, normally grown in suspension, by entrapping them in polymer microbeads. Such entrapment should give increased stability to the normally fragile animal cells, allow for high cell densities to be achieved within the beads and make such preparations suitable for continuous operation. At the same time, the need for separation of the desired product from the cells is obviated. With the model systems studied, we showed that hybridoma, as well as other cell lines entrapped in agarose microbeads, remained viable. Both immunoglobulins and lymphokines were exported through the microbeads into the medium for 1-3 weeks, at levels corresponding well to those produced with free cells.

Animals↗
PubMed1983

Distribution and elimination of poly(methyl methacrylate) nanoparticles after subcutaneous administration to rats.

Poly(methyl [1-14C]methacrylate) nanoparticles were injected subcutaneously into rats. Almost all of the radioactivity stayed at the injection site. After an initial urinary and fecal excretion of approximately 1% of the administered dose per day, the rate of elimination dropped to a low level (approximately 0.005%/day via the feces and approximately 0.0005%/day via the urine) within 70 days. After 200 days, the fecal elimination increased exponentially until a greater than 100-fold increase was observed after 287 days in one rat. After this time, a tendency for an increase in fecal elimination was also observed in the other animals, and the radioactivity in all organs and tissue increased by approximately 100 times in all animals in comparison with the organ radioactivity determinations at earlier times.

Animals↗
PubMed1982

Studies in man with a cold-recombinant live influenza B virus vaccine.

A cold recombinant live influenza B virus vaccine was tested in man. In comparison to a placebo, reactogenicity attributable to virus infection was slight or moderate. No revertant viruses were shed, and there was no evidence of transmission to the placebo group who were housed in close contact with the vaccinees. Serological responses to initial inoculation were moderate; 60% of vaccinees showing twofold increases in serum hemagglutination inhibition (HAI) titers gave a geometric mean titer (GMT) of 1:13. Three weeks after the first vaccination, both the vaccine and the placebo group were revaccinated with homologous live virus vaccine. The group previously given vaccine was resistant to reinfection as judged from clinical reactions and virus shedding and the GMT increased only slightly to 1:16.3. In contrast, the former placebo group responded; mild symptoms were seen, the majority shed viruses and 50% showed twofold increases in serum HAI titers to a geometric mean titer of 1:17.4.

Adult↗
PubMed1982

Killer T cell responses to influenza A during a drift period: studies in mice.

After intravenous immunization of mice with any influenza A H3N2 drift strain attempts to restimulation of cytotoxic T cell (CTL) activities with the same virus or other drift period variants were unsuccessful for up to 6 weeks. Cross-stimulation 4-5 months after primary sensitization yielded, in most situations, positive but lower--as compared to primary--secondary cytotoxic T cell responses. Homotypic challenge was also effective after priming with some influenza A subtypes (A/E/72, A/PC/73, A/T/77) at this time.

Animals↗
PubMed1982

Evaluation of live and inactivated influenza A virus vaccines in a mouse model.

Induction of cross-protective immunity against serologically distinct subtypes of influenza A virus in mice was examined in an attempt to correlate cross-protection with heterotypic lymphocyte responses. Live and inactivated virus vaccines protected against the homologous subtype, but only whole virus protected against heterologous subtypes. Live virus vaccines provided better cross-protection than inactivated virus vaccines. A weak defense against heterotypic challenge generated by live H0N1 virus could be boosted by cross-stimulation with whole H3N2 virus and by restimulation with pathogenic H0N1 virus. Heterotypic protection persisted for at least five months. Live viruses induced cross-reactive cytotoxic T cells in normal mice. However, cross-stimulation with heterologous virus was required to generate secondary cytotoxicity. Cross-reactive B lymphocytes were evident after inoculation with whole virus.

Animals↗
PubMed1981

Long-term studies of microencapsulated and adsorbed influenza vaccine nanoparticles.

Incorporation of antigens into nanometer-sized polymer particles was recently shown to lead to a good adjuvant effect. An optimal antibody response with killed influenza virus antigens was achieved with 0.5% poly(methyl methacrylate). Long-term experiments showed prolonged antibody response of polymer adjuvants with incorporated or adsorbed influenza virus. Adsorption also yielded an optimal adjuvant effect with 0.5% poly(methyl methacrylate). The antibody response was accompanied by protection of the mice against infection with mice-adapted influenza virus. In addition, the polymer vaccines were more stable against temperature inactivation than were vaccines with aluminum hydroxide or without adjuvants.

Adsorption↗
PubMed1980

Studies in man with cold-recombinant influenza virus (H1N1) live vaccines.

Two cold-recombinant influenza A (H1N1) viruses were tested in several groups of human volunteers. Only minor clinical symptoms were seen and no febrile reactions occurred. With serologically primed individuals virus shedding was low, but a high proportion showed rises in serum antibody levels after vaccination and mean titres were high. With serologically unprimed volunteers shedding was high, about 75% yielding viruses but only at low titres and for a short duration. No revertant viruses were found and there was no evidence of transmission to potentially susceptible individuals housed in close contact to the vaccinees. Serum antibody responses with unprimed volunteers were, however, low. Only about one half showed increases in serum antibody titres after vaccination and mean titres were low. Nevertheless, challenge with live attenuated virus indicated a high degree of protection based on virological evidence of infection.

Adult↗
PubMed1980

Studies with a cold-recombinant A/Victoria/3/75 (H3N2) virus. II. Evaluation in adult volunteers.

A cold-recombinant influenza A virus, CR 22, derived from A/Ann Arbor/6/60 (H2N2) cold-adapted virus and A/Victoria/3/75 (H3N2) wild-type virus, was tested in adult volunteers. CR 22 induced only low-grade clinical reactions in volunteers who had low titers of serum antibodies. Virus could be reisolated from about one-third of the volunteers, but only at low titers. No revertant viruses were found, and there was no evidence for transmission of virus to unvaccinated volunteers housed in the close contact with the vaccinees. A high proportion of the volunteers seroconverted, and the mean titers of serum antibody after immunization suggest that a high degree of protection is induced by vaccination with liver CR 22 virus.

Animals↗
PubMed1978

Protection induced by inactivated influenza virus vaccines with polymethylmethacrylate adjuvants.

Nanocapsules from a copolymer of polymethylmethacrylate and polyacrylamide were tested for adjuvant activity in mouse protection experiments with inactivated influenza virus as antigen. Viruses were either adsorbed on the capsules after polymerization or added to the monomers and incorporated by copolymerization after X-ray initiation. Both preparations showed enhanced immunity as compared to fluid vaccine, if the adjuvant content was 1%. The adjuvant effect was comparable to that caused by the mineral adjuvant Al(OH)3. After dilution of the polymer the adjuvant effect was lost. Such synthetic polymers at suitable concentrations could serve as alternatives to mineral adjuvants.

Acrylamides↗
PubMed1978

[A new influenza subunit vaccine: hemagglutinating antibodies one year after vaccination (author's transl)].

The antibody response to a new influenza subunit vaccine was compare d one year after vaccination with the responses induced by two other influenza vaccines. The subunit vaccine was given either in a high dose form containing 2100 IU, or in a low dose form containing 700 IU. As comparison a split vaccine was used containing 800 IU and AI(OH)3 as adjuvant and a whole virus vaccine containing 2100 IU. Of the 399 vaccinated subjects which had taken part in this study 151 were available for hemagglutination inhibiting (HAI) antibody determinations one year after vaccination. Protection rates assessed for the respective groups on the assumption that serum HAI titers of 1 : 32 or greater confer protection. With the high dose of subunit vaccine 85% of volunteers were considered still to have protective titers one year after vaccination, compared with 77% of those who received the whole virus vaccine. Although the high dose subunit vaccine and whole virus vaccine induced similarly high protective levels lasting at least one year, the reactions observed on vaccination were significantly less with the subunit preparation. The lower dose of subunit vaccine induced lower levels of protection (60%) after one year, and lower mean HAI titers than the high dose subunit vaccine. Nevertheless protection was superior to that of the split virus adjuvant vaccine. The addition of adjuvant thus does not seem materially to improve the immune response to influenza virus antigens. An increase of antigen content can however be seen as a practical alternative for achieving higher antibody levels. The subunit vaccine would appear to be particularly suitable in this respect as even with a higher dose there is no increase in reactogenicity.

Adjuvants, Immunologic↗
PubMed1978

[Vaccination of infants and schoolchildren with an influenza subunit vaccine (author's transl)].

A new influenza subunit vaccine which contains only hemagglutinin and neuraminidase antigens was investigated for reactogenicity and immunogenicity in children aged between three and 15 years. Children under six years of age received either 500 IU or 1000 IU of the commercial vaccine, those aged from six to 15 years either 1000 IU or 2000 IU. The vaccines contained the virus strains recommended by the World Health Organisation for the vaccination season 1976/77. In a double blind study the vaccinees were allocated at random to the different dosage groups. The children were examined for reactions by the vaccinating physician 24 hours after vaccination. Serum hemagglutination inhibiting antibody titers were determined before vaccination and four weeks after vaccination. In the younger age-group additional antibody determination was made two weeks after a booster injection. A very low rate of side-reactions was observed in all dosage groups. The increase of the antigen content was not associated with a higher rate of side reactions. After the first vaccination a significant rise of antibody titers could be observed in all children. After the booster injection a further increase of these antibody titers was observed. The response of the younger age group to the dosages 500 and 100 IU did not different significantly. In contrast, in the older age group the increase of the dosage from 1000 to 2000 IU was connected with a better immune response. This was especially marked in the antibody titers against the influenza B-strain virus.

Adolescent↗
PubMed1976

[A new influenza subunit vaccine: reactogenicity and antigenicity in comparison to split and whole virus vaccines (author's transl)].

The reactogenicity and immunogenicity of a new influenza subunit vaccine essentially containing only haemagglutinin and neuraminidase was studied in man. The vaccine was compared to commercially available vaccines, an adjuvant containing tween-ether split vaccine (800 IU per dose), and a fluid whole-virus vaccine (2100 IU per dose). Two dosages (700 and 2100 IU) of the fluid subunit vaccine were compared. All vaccines contained the virus strains recommended by the WHO for the 1975/76 season. In a double-blind study 399 volunteers were randomly selected to receive one of the four vaccines. The volunteers were examined for side-effects 24 and 48 hr after vaccination. Antibodies inhibiting haemagglutination were determined prior to and four weeks after vaccination. The sudunit vaccine at 700 IU per dose caused significantly fewer local side effects than the comparable split vaccine, and resulted in significantly higher antibody titers against both influenza A strains. A comparison of the subunit and whole virus vaccines containing high dosages (2100 IU) showed striking differences in reactogenicity. Subunit vaccine was very well tolerated. whereas whole virus vaccine caused systemic reactions, including fever and headache, in 15% of the volunteers. No significant reactogenicity was seen with a high dosage of subunit vaccine (2100 IU) although this is a three-fold increase on the currently used European dosage. Antibody titers were significantly enhanced however.

Adolescent↗
PubMed1975

Potency of influenza vaccines: mouse protection experiments in correlation to field studies in man.

The seroconversion rates have been studied following vaccination of human volunteers with two commercial influenza vaccines. Vaccine A did not give a significant increase of hemagglutination-inhibition titers. Vaccine B, on the other hand, raised the titers 2- to 8- fold, depending on the pretiters of the individuals. The potency of the same vaccines has been tested using mouse protection experiments: vaccine B gave significantly better protection rates, as measured by survival as well as by reduction of lung lesions. These results give additional evidence that the use of mouse protection experiments for the evaluation of different influenza vaccines is meaningful.

Aerosols↗
PubMedDate not supplied

Inhibition of chemotactic migration of human neutrophilic granulocytes by recombinant human granulocyte-macrophage colony-stimulating factor.

Human recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) was analysed for effects on the migration of human neutrophilic granulocytes by the Boyden chamber assay. At concentrations ranging from 0.1 to 10,000 U/ml (or 10(-12) to 10-mol/l) GM-CSF had neither chemokinetic nor chemotactic activity. When added to the cells in the upper compartment of the chamber GM-CSF dose-dependently inhibited the chemotactic migration towards the tripeptide f-Met-Leu-Phe and the complement split product C5a. Chemotaxis towards f-Met-Leu-Phe was inhibited more efficiently by GM-CSF than C5a-induced migration.

Chemotaxis, Leukocyte↗