In vitro production of new types of hemophilus influenzae.

Two new types of Hemophilus influenzae, Sab and Sad have been produced in vitro. Each exhibits the presence of the type specific polysaccharides of 2 types of E. influenzae within the same cell. In Sab the polysaccharides of types a and b have been demonstrated and in Sad those which characterize types a and d. The Sab and Sad traits are inherited. Sab was produced by the action of DNA-containing extract isolated from type a on either type b cells or Rb cells (non-encapsulated non-type-specific cells derived from type b). Sad cells were formed as a result of the action of the DNA-containing extract isolated from type d on cells intermediate between Rab and Sab cells. DNA-containing extracts isolated from Sab cells have induced the Sab trait in Rd cells with predictable regularity. Evidence has been presented that the hereditary determinant of Sab cells is a new genetic substance with new functions. Therefore, the interaction of the DNA-containing substance from cells of one genetic type with living cells of a genetically different type has produced what appears to be a new individual which differs from each of the cells contributing the differing genetic traits but has at least one trait in common with each. Sab cells derived presumably from a single cell show the appearance of type b cells sometime during the first 7 generations.