PubMed · 9231463
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Y Scott, B McArdle, P I Parker. 1997. Column agglutination technologies.. https://pubmed.ncbi.nlm.nih.gov/9231463/
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To study the receptor specificity of modern human influenza H1N1 and H3N2 viruses, the analogs of natural receptors, namely sialyloligosaccharides conjugated with high molecular weight (about 1500 kDa) polyacrylamide as biotinylated and label-free probes, have been used. Viruses isolated from clinical specimens were grown in African green monkey kidney (Vero) or Madin-Darby canine kidney (MDCK) cells and chicken embryonated eggs. All Vero-derived viruses had hemagglutinin (HA) sequences indistinguishable from original viruses present in clinical samples, but HAs of three of seven tested MDCK-derived isolates had one or two amino acid substitutions. Despite these host-dependent mutations and differences in the structure of HA molecules of individual strains, all studied Vero- and MDCK-isolated viruses bound to Neu5Ac alpha2-6Galbeta1-4GlcNAc (6'SLN) essentially stronger than to Neu5Acalpha2-6Galbeta1-4Glc (6'SL). Such receptor-binding specificity has been typical for earlier isolated H1N1 human influenza viruses, but there is a new property of H3N2 viruses that has been circulating in the human population during recent years. Propagation of human viruses in chicken embryonated eggs resulted in a selection of variants with amino acid substitutions near the HA receptor-binding site, namely Gln226Arg or Asp225Gly for H1N1 viruses and Leu194Ile and Arg220Ser for H3N2 viruses. These HA mutations disturb the observed strict 6'SLN specificity of recent human influenza viruses.
Monoclonal antibody (MAb) 8aC10 against Salmonella O:5 antigen was obtained after immunization of BALB/c mice with live attenuated mutant of Salmonella typhimurium. Antigen specificity of the MAb was characterized by ELISA, immunoblotting, passive hemagglutination (PHA), passive hemolysis and agglutination tests. In ELISA, PHA and immunoblotting the MAb reacted only with lipopolysaccharides (LPS) of Salmonella strains from group O:4 (B), expressing O:5 antigen. The MAb agglutinated in addition Salmonella strains with O:8 antigen from group C(2)-C(3) but did not react with purified LPS. These results demonstrate O:5 specificity of MAb 8aC10. Cross-agglutination with group C(2)-C(3) suggests the presence of similar but not identical epitope in O:8 expressing strains, which is possibly localized onto O-acetyl-abequose and abequose residues bound with a alpha-1-->3 linkage to the basic polysaccharide backbone of Salmonella LPS with O:5 and O:8 antigen respectively.
Duration of immunity in dogs induced with current commercial inactivated leptospirosis vaccines and evaluated against experimental infection, to date, has hardly been documented. The purpose of the present work was to assess the duration of immunity in dogs that is attainable with a commercial inactivated bivalent leptospirosis vaccine. For this purpose, young dogs were vaccinated twice followed by challenge with either Leptospira interrogans serovar canicola or L. interrogans serovar icterohaemorrhagiae 5 weeks, 27 weeks or 56 weeks after the second vaccination. For assessment of the duration of immunity, titres of agglutinating serum antibodies were measured before and after challenge, and the effects of challenge on a variety of parameters were determined including reisolation of challenge organisms from blood, urine and kidney. Both challenge strains induced a generalised infection in control dogs, the canicola strain being most virulent. From the results with different parameters it appeared that the two vaccinations induced a high rate of protection from generalised infection with canicola and icterohaemorrhagiae at 5, 27 and 56 weeks after the second vaccination. In addition, after 56 weeks, still a high level of immunity against renal infection with sv. canicola and, as a consequence, urinary shedding of sv. canicola bacteria, was demonstrated. It was, therefore, concluded that with this vaccine, using this vaccination schedule, a duration of immunity of 1 year can be attained against infection with both serovars.