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STUDIES ON THE MECHANISM OF IMMUNITY IN TYPHUS FEVER : II. ALLERGIC AND TOXIC REACTIONS PRODUCED WITH RICKETTSIA
1Department of Bacteriology and Immunology of The Harvard Medical School, Boston.
The Journal of Experimental Medicine
|October 30, 2009
Summary
Immune guinea pigs inoculated with Mexican typhus virus show accelerated local skin reactions. A heat-labile substance in formalinized Rickettsiae elicits reactions in normal animals, suggesting a phenomenon akin to Koch
Area of Science:
- Immunology
- Microbiology
- Virology
Background:
- Intradermal inoculation of Mexican typhus virus into immune guinea pigs elicits a local skin reaction.
- This reaction in immune animals appears earlier and resolves faster than in normal guinea pigs.
Purpose of the Study:
- To investigate the characteristics of local skin reactions following typhus virus inoculation in immune and normal guinea pigs.
- To determine the role of heat-killed or formalin-killed Rickettsiae in eliciting reactions in immune animals.
- To identify the nature of the substance responsible for skin reactions in normal animals.
Main Methods:
- Intradermal inoculation of Mexican typhus virus into immune and normal guinea pigs.
- Intradermal injection of heat-killed or formalin-killed Rickettsiae into typhus-immune guinea pigs.
- Observation and recovery of virus from local lesions.
- Intradermal injection of formalinized Rickettsiae into normal guinea pigs and humans.
- Heat inactivation of formalinized Rickettsia suspensions.
Main Results:
- Immune guinea pigs exhibited accelerated and shorter-lived local skin reactions compared to normal animals.
- Heat-killed or formalin-killed Rickettsiae did not induce significant reactions in immune guinea pigs.
- Typhus virus was recovered from local lesions in immune guinea pigs up to 72 hours post-injection.
- Normal guinea pigs and non-immune humans showed transient skin congestion and swelling upon injection of formalinized Rickettsiae.
- Heating formalinized Rickettsia suspensions at 70°C for 30 minutes rendered them inactive in normal subjects.
Conclusions:
- The observed reactions in typhus-immune guinea pigs resemble Koch's phenomenon in tuberculosis and accelerated takes in vaccinia virus revaccination.
- A heat-labile substance present in formalinized Rickettsia bodies is responsible for inducing skin reactions in normal individuals.
- These findings highlight specific immune responses to typhus virus and Rickettsiae.
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