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THE ANTIGENIC RELATIONSHIP BETWEEN PROTEUS X-19 AND TYPHUS RICKETTSIA : II. A STUDY OF THE COMMON ANTIGENIC FACTOR

M R Castaneda1

  • 1Department of Bacteriology and Immunology, The Harvard Medical School, Boston.

The Journal of Experimental Medicine
|October 30, 2009
PubMed

Insights

Researchers identified a common soluble specific factor between Mexican typhus Rickettsia and Proteus OX-19. This shared factor, likely a polysaccharide, is responsible for the Weil-Felix reaction in typhus diagnostics.

Area of Science:

  • Microbiology
  • Immunology
  • Rickettsial Diseases

Background:

  • The Weil-Felix reaction is a serological test used to diagnose typhus group rickettsioses.
  • This reaction involves agglutination between patient serum and specific strains of Proteus bacteria.
  • The underlying antigenic relationship between Rickettsia and Proteus strains has been a subject of investigation.

Purpose of the Study:

  • To isolate and characterize the soluble specific substance from Mexican typhus Rickettsia.
  • To compare this substance with polysaccharides from B. proteus OX-19.
  • To elucidate the antigenic basis of the Weil-Felix reaction.

Main Methods:

  • Isolation of a soluble specific substance from Mexican typhus Rickettsia.
  • Precipitation reactions using Proteus X-19 antiserum and typhus human serum.
  • Chemical tests including Molisch reaction and biuret test to determine the nature of the substance.

Main Results:

  • A soluble specific substance was isolated from Mexican typhus Rickettsia.
  • This substance exhibited identical precipitation reactions to polysaccharides from B. proteus OX-19.
  • The substance showed characteristics of a polysaccharide (positive Molisch, heat stable, negative biuret) but contained 7% nitrogen.
  • A common soluble specific factor was identified in both typhus Rickettsia and Proteus X-19.

Conclusions:

  • A shared soluble specific factor exists between typhus Rickettsia and Proteus X-19.
  • This common factor is likely responsible for the serological cross-reactivity observed in the Weil-Felix reaction.
  • The substance is predominantly polysaccharide in nature, though further investigation into its exact composition is warranted.

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