[An immunological analysis of bacterial persistence in the bone marrow]

A method for the evaluation of bacterial persistence in the bone marrow in association with particular clonogenic target cells was developed. The method was based on the negative selection of cells expressing microbial antigens after treatment with hyperimmune antiserum specific to a given infective agent and the subsequent quantitation of target cells thus eliminated in appropriate assays. Using this approach, we demonstrated that Mycoplasma arthritidis and L-forms of Streptococcus strain L-406 were capable of persisting in murine bone marrow in close association with CFUs-7 (a subpopulation of hematopoietic stem cells) for at least several months after experimental infection. Francisella tularensis was also found to be capable to express on the CFUs-7 membranes. Persisting microorganisms enhanced both proliferation and migration of CFUs-7.