So-called antireceptor sera

Experiments in delayed type hypersensitivity transfer were carried out with the aim of studying the ability of rabbit antisera against peritoneal exudate cells of rats sensitized with bovine gamma globulin or rabbit kidney tissue antigen to block peritoneal exudate cells of guinea pigs. In the serological test the antisera prepared against the cells of sensitized rats and tentatively named "receptor antisera", reacted not only with the cells of these rats, respectively, but also with guinea pig cells. In hypersensitivity transfer experiments in guinea pigs receptor antisera showed a blocking effect on the transferred cells, making them incapable of transferring hypersensitivity, i. e. rabbit antisera against rat peritoneal exudate cells reacted with guinea pig cells. This interaction was specific: the blocking effect was manifested only when guinea pigs whose cells were used in the transfer were sensitized with the same antigen as the rats against whose cells the receptor antisera had been prepared. The control antisera, taken for the treatment of the transferred cells in the same doses as the receptor antisera, had no blocking effect on the cells.     

Anti-DNA.RNA sera

Summary The specificity of anti-nucleic acid antisera can immunocytochemically be evaluated with test systems which apply various nucleic acids immobilized to inert matrices. When using polyrA.polyrU as a model compoud for dsRNA, it is important to prevent the formation of the triple stranded form polyrA.(polyrU)₂.Anti-dsRNA antibodies which, when tested with the correct test system, proved to be present in an earlier described anti-DNA.RNA serum, could be removed by adsorption. By cytofluorometric comparison of the immunofluorescence signals obtained with the anti-dsRNA containing serum and the absorbed serum, it could be shown that the anti-dsRNA antibodies do not contribute to the specific signals measured after in situ hybridization.Repetitive incubations with the anti-DNA.RNA serum led to a considerable increase in immunofluorescence signal.This work was subsidized in part by Het Praeventiefonds, The Hague, The Netherlands     

Glycosaminoglycan sulfotransferases in human and animal sera

Heparan sulfate, keratan sulfate, chondroitin, chondroitin 4/6-sulfate (80% 4-sulfate and 20% 6-sulfate), and UDP-N-acetylgalactosamine 4-sulfate were used as acceptors for the measurement of 3'-phosphoadenylyl sulfate: glycosaminoglycan sulfotransferase activities in human serum. Chromatographic fractionation of the serum followed by determination of the sulfotransferase activities demonstrated the existence of at least four different sulfotransferases capable of introducing sulfate to 1) position 6 of the internal N-acetylgalactosamine units of chondroitin, 2) position 6 of the nonreducing terminal N-acetylgalactosamine 4-sulfate unit of chondroitin 4/6-sulfate, 3) position 2 (amino group) of the glucosamine units in heparan sulfate, and 4) the sugar units in keratan sulfate, respectively. The fourth activity was separated into two subfractions with different specificities for the structure of neighboring sugars of the sulfate-accepting sugar units. No major variations in the sulfotransferase activities on added receptors were found to occur in sera from individuals 22-41 years old. In contrast, the activities in sera of various mammalian and avian species showed a species-specific variation. With mouse skin fibroblasts cultured in serum-free medium, preferential secretion of several sulfotransferases could be demonstrated. The results, taken together, suggest that the appearance of the sulfotransferases in serum is not a fortuitous event due to nonspecific cell death, but the result of an elaborate mechanism for enzyme secretion by a cell or tissue system.     

Lytic and bactericidal properties of salmonid sera

There are two types of haemolytic activity against heterologous red blood cells in the sera of fishes including salmonids: a specific antibody-dependent complement-mediate activity 'CH₅₀' and a natural, non-specific activity 'SH₅₀'. Sera of coho salmon, Oncorhynchus kisutch , masu salmon, O. masou , rainbow trout and steelhead trout, Salmo gairdneri , were assayed for CH₅₀ and SH₅₀ activities by incubation at 30°C for 60 min with goldfish red blood cells (GFRBC) sensitized with the rainbow trout antiGFRBC serum and unsensitized GFRBC for CH₅₀ and SH₅₀, respectively. SH₅₀ activity was usually half that of CH₅₀ in each serum. In healthy individuals, both CH₅₀ and SH₅₀ activities were confined to a narrow range specific for each species. While EDTA abolished both haemolytic activities, moieties of the activities remained in the presence of EGTA. Incubation with lipopolysaccharide and zymosan reduced both CH₅₀ and SH₅₀ activities. Fish serum possessed a natural, powerful bactericidal action, which for Aeromonas salmonicida was proportional to the level of SH₅₀ activity. Changes in the SH₅₀ activity were related to starvation and infectious diseases. The SH₅₀ activity decreased as the diseases (furunculosis and vibriosis) progressed.