Studies on delayed hypersensitivity of antigens isolated from Mycoplasma pneumoniae cells.

Cells of Mycoplasma pneumoniae Mac strain were fractionated into acetone-soluble and insoluble fractions. Acetone-insoluble fractions were digested with pronase and further purified by chromatography on Sephadex G-75, yielding three water-soluble fractions which were free from lipid and consisted mainly of polysaccharide-protein complex. All these water-soluble fractions possessed eliciting antigenicity to delayed hypersensitivity for M. pneumoniae as measured by skin reactions and macrophage migration inhibition tests, but not to complement-fixing antibodies. In contrast, the acetone-soluble fraction was reactive with the complement-fixing antibodies but not for the delayed hypersensitivity.