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The skin-reactive antigens of Mycoplasma pneumoniae
Abstract:
Guinea pigs experimentally infected with Mycoplasma pneumoniae or immunized with the orgnaism in combination with Freund's complete adjuvant developed a delayed hypersensitive skin reaction following on intradermal injection of the M. pneumoniae antigen. The amount of protein necessary to produce the delayed skin reaction was as low as 0.01 mug. When the sonicated whole cells were extracted with aqueous acetone, the delayed skin reactivity was found mostly in the acetone insoluble (lipid-depleted) fraction. On the other hand, the lipid fraction which was isolated by a chloroform-methanol extraction of the acetone-soluble fraction and had a high titer of complement-fixing activity, exhibited little delayed skin reactivity. The lipid-depleted antigens as the whole cell antigens produced delayed skin reactivities in human patients.
Insights
Mycoplasma pneumoniae antigens induce delayed hypersensitivity skin reactions in guinea pigs and humans. Lipid-depleted fractions are most effective, while lipid fractions show minimal reactivity.
Area of Science:
- Immunology
- Microbiology
Background:
- Mycoplasma pneumoniae is a significant human respiratory pathogen.
- Understanding the immunological response to M. pneumoniae is crucial for developing diagnostics and vaccines.
Purpose of the Study:
- To investigate the antigenic components of Mycoplasma pneumoniae responsible for delayed hypersensitivity skin reactions.
- To differentiate the roles of lipid and lipid-depleted fractions in eliciting immune responses.
Main Methods:
- Experimental infection and immunization of guinea pigs with M. pneumoniae.
- Intradermal injection of M. pneumoniae antigens and fractions.
- Fractionation of M. pneumoniae cells using aqueous acetone and chloroform-methanol extraction.
- Assessment of delayed hypersensitivity skin reactions and complement-fixing activity.
Main Results:
- Guinea pigs infected or immunized with M. pneumoniae developed delayed hypersensitivity skin reactions.
- The acetone-insoluble (lipid-depleted) fraction contained the primary delayed skin reactivity.
- The lipid fraction exhibited high complement-fixing activity but low delayed skin reactivity.
- Lipid-depleted antigens elicited delayed skin reactions in human patients.
Conclusions:
- Lipid-depleted components of Mycoplasma pneumoniae are key inducers of delayed-type hypersensitivity.
- The immunological response to M. pneumoniae involves distinct fractions with different activities.
- These findings have implications for M. pneumoniae antigen-based diagnostics and immunotherapies.