A Staphylococcus aureus enterotoxin-B induced type 1 immediate hypersensitivity reaction in a goat.

A Nigerian dwarf goat intended for the production of antibodies to staphylococcal enterotoxin-B exhibited classical signs of a type 1 anaphylactic reaction 2 to 3 min after parenteral introduction of this antigen. The exquisite sensitivity demonstrated in concert with the pathognomonic signs appeared to make the breed and species an excellent model for the further study and interpretation of this syndrome in domestic food animals.

Flavonoids protect against T-2 mycotoxins both in vitro and in vivo.

Quercetin was able to reduce the cytotoxic effect of T-2 mycotoxin on cultured murine thymocytes. When given to mice immediately before challenge with T-2 mycotoxins, quercetin significantly reduced mortality.

Cross reactions among serogroup B meningococci assayed by kinetic complement fixation assay.

The surface antigens of five prototype serogroup B strains were investigated by a rapid turbido-haemolytic complement fixation assay. Several cross-reactions among the serotypes were detected. It is suggested that antigenic determinants accessible for antigen-antibody interaction need not be immunogenic.

Rapid rate-kinetic turbidometric assay for quantitation of viral complement-fixing antibodies.

A rapid rate-kinetic turbidometric assay for the quantitation of viral complement fixing antibodies has been developed, using adenovirus as a model. The procedure is based on the turbidometric quantitation of intact sheep erythrocytes and measures the rate of hemolysis (change in absorbance at 640 nm/min/), at maximum velocity, occurring in the presence of residual complement not fixed by the antigen-antibody reaction. Reagents were standardized and assays performed using a microprocessor-controlled spectrophotometer with kinetic assay capability and a thermoregulated cell compartment. Eleven sera were assayed for complement fixing antibodies both by the conventional microtiter technique and by the rapid turbidometric method described here. Good correlation (r = 0.89) was obtained between the two procedures. Unlike the conventional complement fixation test, the rate-kinetic turbidometric complement fixation assay was found to be tolerant of variation in complement and antigen concentration, endpoint titers were objectively quantitated and, once reagents had been standardized, results could be obtained within 45-60 min. The technique is potentially adaptable to large-scale automation.

In vitro toxicity of T-2 mycotoxin in mouse lymphoid cells.

The in vitro toxicity of T-2 toxin towards mouse lymphoid cells prepared from spleen, thymus, peritoneal lavage and bone marrow cells was studied. Bone marrow cells were more resistant to damage by T-2 toxin than thymus, spleen and peritoneal cell preparations.

Single radial hemolysis test for quantitation of complement-fixing antibodies to non-hemagglutinating viruses.

A single radial hemolysis test, which overcomes many of the problems of conventional complement fixation tests, was developed for the quantitation of virus complement-fixing antibodies. The test procedure utilized staphylococcal protein A-coated sheep erythrocytes immobilized in agarose into which antigen was incorporated. Undiluted heat-inactivated serum samples were allowed to diffuse radially from wells punched in the agarose. Protein A served to concentrate the subsequent antigen-antibody reaction on the surface of the erythrocytes. Zones of hemolysis were developed by flooding with complement. With adenovirus as a model, basic test parameters were defined, and optimum reagent concentrations and diffusion conditions were determined. A positive linear relationship was found to exist between zone diameter and increasing log concentration of specific antiserum. No correlation was found between zone diameter and total concentration of immunoglobulin G in test sera. Sera rendered anticomplementary by the addition of carrageenan produced hemolytic zones equal to diameter to those observed with untreated sera. Seventy-seven human sera with known complement fixation titers were tested by this method. Good correlation (r = 0.74) between the complement fixation test and single radial hemolysis was observed. This test was highly reproducible and more sensitive than the conventional complement fixation test.

Identification of 4,6-O-(1-carboxyethylidene)-D-galactose by combined gas chromatography mass spectrometry.

Combined gas chromatography mass spectrometry was used to separate and identify a carrageenan component suspected of being the acid ketal 4,6-O-(1-carboxyethylidene)-D-galactose. The mass spectral fragmentation pattern is presented as evidence of the presence of this component in the carrageenan from Petrocelis middendorfii (P. franciscana).