Group-specific polysaccharide was extracted from group A streptococci by various methods and after purification it was adsorbed on to polystyrene latex particles, which were used in an agglutination test to detect group-specific antibody in hyperimmune rabbit sera, The most pure and serologically specific extracts were obtained by extraction with formamide. Formamide-extracted polysaccharides of groups A-var, B, C, G and L were also adsorbed on to latex particles. Inter-group cross-agglutination reactions corresponded to known chemical relationships between group polysaccharides. Latex agglutination tests were used to detect group .A and A-var antibodies in human sera. Antibodies were found in 90% of patients suspected of suffering from streptococcal disease but in less than 40% of controls. In paired sera from patients with known streptococcal infections, initial antibody titres were high in most cases. M-proteins from group A streptococci belonging to a number of types were extracted with hot acid and precipitated with 30% and with 60% saturated ammonium sulphate. The precipitates were designated P30 and P60 respectively. The supernatant (S60) was further purified by precipitation at pH 5.5 and washing with absolute alcohol. Immunological tests showed that purified S60 fraction was more type-specific than P60 fraction. Absorption of rabbit hyperimmune M antisera with S60 fraction removed the specific bactericidal activity. The purified S60 was used in latex agglutination tests to detect type-specific M antibodies in human sera. Sera from patients suspected of suffering from streptococcal infection and from control persons showed no significant difference in the number of serotypes for which antibody was present in high titre. Most of the paired sera from patients who had suffered from infection with group A streptococci of known serotype showed a significant rise in antibody titre to the infecting serotype. Rises in titre to heterologous serotypes also occurred frequently, but showed no constant pattern. This thesis is a report of full-time research undertaken by the author in the Cross-infection Reference Laboratory, Central Public Health Laboratory, Colindale, London, N.W.9, and in the Wright-Fleming Institute, St. Mary's Hospital Medical School, London, W.2 from April, 1966 to August, 1968. An account of a part of this work is in preparation and will be submitted for publication as fo11ows: Erwa, H.H., Maxted, W.R. & Brighton, W.D. (1968) "A latex agglutination test for the measurement of antibodies to group-specific streptococcal polysaccharides."
Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:623014 |
Date | January 1968 |
Creators | Erwa, Hashim Hassan |
Contributors | Williams, Professor R.E.O |
Publisher | Imperial College London |
Source Sets | Ethos UK |
Detected Language | English |
Type | Electronic Thesis or Dissertation |
Source | http://hdl.handle.net/10044/1/15788 |
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