Hepatitis C virus replication kinetics in chimpanzees with self-limited and chronic infections.

The availability of molecular beacon-based, real time polymerase chain reaction (PCR) and a semi-automated sample extraction procedure have made it possible for us to retrospectively examine HCV replication kinetics in HCV naive chimpanzees infected during the past 20 years. We compared these in 17 animals that developed chronic infection, and in 21 that developed self-limited infection. No differences were found in infecting dose, or replication kinetics in the acute phase between these two types of infection. An unanticipated finding was the fact that 10 of 17 animals developing chronic infection partially controlled virus replication for 48 +/- 48 weeks after typical acute phase viraemia, and prior to development of chronic infection. Twenty-nine out of 30 (29/30) sera, which were negative by quantitative PCR during the downregulated period, were, however, positive by the more sensitive Genprobe isothermal transcription-mediated amplification (TMA) assay. Thus, downregulation was not complete. Ten animals showing self-limited infection showed complete resolution of viraemia by TMA assay. Quasispecies analysis revealed that in all, except one case, the virus reappearing after downregulation was essentially identical to that of the originally infecting virus.

Monoclonal antibodies specific for Campylobacter fetus lipopolysaccharides.

Four monoclonal antibodies (mAbs) (M1357, M1360, M1823 and M1825) which reacted with Campylobacter fetus lipopolysaccharide (LPS) core region epitopes were produced and characterized. Reactivity of these mAbs with C. fetus core LPS epitopes was determined by enzyme-linked immunosorbent assay (ELISA) with whole cell proteinase K digests and phenol-water extracted LPS, and by immunoblotting with proteinase K digests. The specificities of the four mAbs were evaluated using an indirect ELISA. One of the mAbs reacted with 42 and three of the mAbs reacted with 41 of the 42 C. fetus strains examined. No reaction was observed between the four mAbs and 32 non-C. fetus bacteria tested, with the exception of one mAb with one organism. The four mAbs reacted with serotype A and B strains indicating the presence of shared epitopes in C. fetus LPS core oligosaccharides. The specificities of three mAbs previously produced to C. fetus LPS O-antigens (M1177, M1183 and M1194) were also evaluated and no reaction was observed with these mAbs and the 32 non-C. fetus bacteria tested. Strong immunofluorescence reactions were observed with the anti-O chain mAbs and selected C. fetus strains of the homologous serotype. These anti-LPS core oligosaccharide and anti-LPS O chain mAbs are highly specific for C. fetus and are potentially useful as immunodiagnostic reagents for detection, identification and characterization of C. fetus.

Identification, characterization, and variation in expression of two serologically distinct O-antigen epitopes in lipopolysaccharides of Campylobacter fetus serotype A strains.

Monoclonal antibodies (MAbs) to the lipopolysaccharide (LPS) O-antigens of Campylobacter fetus serotype A and B strains were produced. Eight MAbs specific for serotype A LPS were characterized on immunoblots of C. fetus serotype A LPS. Two immunoblot patterns were observed and were used to divide the eight MAbs into two groups. MAbs M1177 and M1194 were selected as representative of the two groups and were used in an enzyme-linked immunosorbent assay (ELISA) to examine the LPS O-antigen epitopes of 37 serotype A C. fetus subsp. fetus and C. fetus subsp. venerealis strains. Thirty-three strains (89%) reacted with both M1177 and M1194, 2 strains reacted only with M1177, and 2 strains reacted only with M1194. To further characterize the O-antigen epitopes, purified serotype A LPS was treated using various temperature and pH conditions and the effect of the treatments on the reactivity of the LPS with MAbs M1177 and M1194 was evaluated by ELISA. While no difference among several treatments was observed, heating serotype A LPS under alkaline conditions decreased the reaction with M1177 to background levels and increased the reaction with M1194. MAbs M1177 and M1194 were also used with ELISA to investigate in vivo and in vitro expression of the two O-antigen epitopes. There was substantial variation in expression of the two epitopes among weekly isolates of two C. fetus serotype A strains recovered from experimentally infected heifers. There was minimal variation in expression of the two epitopes in successive subcultures of three C. fetus serotype A strains.

Enzyme linked immunosorbent assay for potency testing of vaccines containing Clostridium perfringens type D epsilon-toxoid.

For ethical, economic and technical reasons in vivo assays need to be replaced in routine laboratory procedures. Based on a method which is already accepted by the British authorities, an indirect ELISA has been developed and evaluated for Clostridium perfringens type D-containing vaccines. Individual and pooled sera of vaccinated rabbits were tested at a single dilution level, the results transferred into IU/ml, and compared with the conventional toxin neutralization test in mice. The ELISA was found to give reproducible estimates of antitoxin levels and showed good correlation with the conventional in vivo test in mice.

[Veterinary aspects of raising chimpanzees]. / Tierärztliche Aspekte zur Haltung von Schimpansen.

The problems involved in chimpanzee husbandry are mainly baised on their behaviour, intelligence and psychical sensitivity. The most suitable species-specific conditions of keeping, feeding and veterinary welfare are fundamental demands for physical and mental health as well as for successful reproduction of chimpanzees living in captivity. In spite of different possibilities and motives of chimpanzee husbandry in each particular case, the general statements given in this article may be useful concerning these requirements.

[Comparative studies on the DNA synthesis of rat thymus and spleen cells in vitro under the influence of x rays, UV light and radiomimetic compounds]. / Vergleichende Untersuchungen zur DNA-Synthese von Thymus- und Milzzellen der Ratte in vitro unter dem Einfluss von Röntgenstrahlen, UV-Licht und radiomimetisch wirksamen Verbindungen.

In order to further characterize the different repairing behavior of thymus and spleen cells of rats in vitro under the influence of X-rays, UV radiation and methylmethanesulfonate (MMS), the effect of bleomycin (BM), L-cysteine (CY-E), N-ethylmaleimide (NEM), 1-beta-D-arabinofuranosylcytosine (araC), dideoxythymidine (ddT), and novobiocin (NB) on the semiconservative and restorative DNA synthesis as well as on the behavior of DNA under the alkaline elution was studied. The semiconservative DNA synthesis was inhibited by all examined agents except ddT, the restorative DNA synthesis only by NEM, araC, and NB. The stimulation of the restorative DNA synthesis was increased by UV radiation and MMS in spleen cells and by X-rays, BM and CY-E in thymus cells. Under the conditions of alkaline elution, there was a more sensitive reaction of spleen cells than of thymus cells to X-rays, BM and CY-E. The results show that thymus cells are especially qualified for the repair of short chains and spleen cells for the repair of long chains.