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Biomedical subjects

H Ashworth

Publications and source records attributed to H Ashworth.

8 recordsLinked to original sources

Improved streptococcal grouping antisera containing polyethylene glycol.

Antisera to streptococcal groups A through G containing 4% polyethylene glycol 6000 were prepared and evaluated. Seventy strains of homologous and heterologous beta- and non-beta-hemolytic streptococci were included in the evaluation. Homologous reactions were determined against extracts prepared by four extraction methods: hot hydrochloric acid (Lancefield) extraction, autoclave extraction, hot formamide extraction, and nitrous acid extraction. Enhancement of the precipitin reaction in the presence of polyethylene glycol 6000 permitted a fourfold dilution of all antisera for use in the capillary precipitin test. At this dilution, the potency of the antisera exceeded requirements established for these reagents.

Cross Reactions

Looking back.

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Education, Medical, Undergraduate

Cross-protective antigens of group A streptococci types 3 and 31 and types 46 and 51.

Reciprocal cross-protective antigens have been demonstrated between types 3 and 31 cocci, and one-way cross-protective antigens have been demonstrated between types 46 and 51 cocci. The reciprocal cross-protective antigen of types 3 and 31 is distinct from the specific M protein of either type. In the one-way cross relationship, type 46 cocci contain both type 46 and type 51 M proteins and therefore stimulate protective antibodies against both types. Type 51 cultures contain only the homologous M antigen. These relationships were demonstrated by capillary precipitin tests, indirect bactericidal tests, and in agar-gel diffusion patterns. The practical significance of these relationships in the serological typing of group A streptococci is discussed along with their possible role in immunity to streptococcal infections in man.

Animals

Absorption of group A streptococcus anti-M typing sera with broken cells.

Group A streptococcus anti-M typing sera that cannot be made specific by absorption with whole streptococcus cells have been absorbed with the soluble and insoluble fractions of ruptured heterologous cells. The technique has been used successfully for preparing specific anti-M sera against eight serotypes of group A streptococcus. The method involves breakage of the absorbing cells in the presence of the antiserum, and incubation of the mixture at 37 C for 1 hr, followed by 3 to 5 days of incubation at 4 C. The procedure is useful for preparing specific antiserum from certain lots of unabsorbed antiserum that otherwise would have to be discarded because of undesirable cross-reactivity.

Immune Sera

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Recreation

Where's nurse?

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Humans