A competitive enzyme immunoassay for detection of Salmonella sp. was developed in order to provide a sensitive assay for same-day identifzcation of Salmonella sp. The assay could be performed in about 90 min and consisted of the following steps. Lipopolysaccharide derived from Salmonella typhimurium was used to passively coat polystyrene 96-well plates and tubes. A titrated amount of monoclonal antibody specijc for an outer lipopolysaccharide core epitope commonly found in Salmonella sp. was mixed with the prepared test sample prior to adding the mixture to the antigen coated matrix. Antibody bound to the immobilized antigen was detected with horseradish peroxidase labelled goat antimouse IgG (H&L chain).The analytical sensitivity of the assay was 3. I ng and 5.6 ng of lipopolysaccharide per ml for the plate and tube formats, respectively, if25% inhibition or less was considered negative. This cutof level was based on reactivity of unrelated monoclonal antibodies with S . typhimurium lipopolysaccharide and lipopolysaccharide from E. coli with the Salmonella specijc monoclonal antibody in the assay.
Six different hybridoma cell lines were obtained producing IgM monoclonal antibodies (MAbs) against human blood group A antigen. All these MAbs agglutinate the A1, A1B and A2 erythrocytes, while only one of them agglutinates the A2B erythrocytes. The agglutination activity of 3 of these MAbs is inhibited by N-acetyl-D-galactosamine (D-GalNAc). Dissociation constants of complexes of these MAbs with D-GalNAc are approximately 2.2 X 10(-3) mol/l.
SUMMARY
H‐2‐linked genes which control popliteal lymph node (PLN) immune responses to the H‐Y antigen were analysed. It was found that at least two genes or two groups of genes are involved in the genetic control and are responsible for the four variants of relations observed between the primary and the secondary response: +/‐, +/+, ‐/+ and ‐/‐ (+' and ‐' stand for a high and a low response, respectively). The results obtained with H‐2 recombinant haplotypes indicated that the genes controlling the primary and secondary responses map to the left and to the right of the Eα locus, respectively. A high primary response was observed in the presence of b alleles at K, Aβ, Aα, and Eβ loci, whereas a high secondary response occurred only in the presence of d alleles in the chromosomal segment between Eα and D loci. From the experiments with F1 hybrids it is clear that low secondary responses are, for the most part, dominant and that the two seemingly separate control mechanisms for the primary and secondary responses may interact.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.