title: A rapid [3H]glycerol radioassay for determination of monocyte-mediated growth inhibition of Mycobacterium avium.
abstract: [3H]glycerol was used to radiolabel Mycobacterium avium (MA) bacteria after interaction with human monocytes in a rapid in vitro assay for determination of the growth inhibition of the mycobacteria by monocytes. Monocytes and MA were co-cultured in 96-well microtiter plates for 1-5 days, and [3H]glycerol was added for an additional 3 days of incubation to radiolabel residual bacteria. The results indicate that monocytes inhibited mycobacterial growth within 24 h of co-culture, an activity which increased during incubation until optimal growth inhibition was noted by 3-4 days. A comparison with conventional plate counting methodology demonstrated similar responses between the two assays except that the conventional assay required 2-3 weeks of culture before visible MA colonies could be detected and enumerated. Thus, the development of a rapid radiolabel assay to quantitate the interaction between monocytes and MA will facilitate the investigation of normal host responses to this opportunistic pathogen.
authors.affiliation: University of South Florida College of Medicine, Department of Medical Microbiology and Immunology, Tampa 33612.
authors.forename: D K
authors.initials: DK
authors.lastname: Blanchard
authors.forename: M B
authors.initials: MB
authors.lastname: Michelini-Norris
authors.forename: J Y
authors.initials: JY
authors.lastname: Djeu
mesh_terms: D015169:Colony Count, Microbial; D005990:Glycerol; D006801:Humans; D007553:Isotope Labeling / Q000379:methods*; D009000:Monocytes / Q000382:microbiology*; D009162:Mycobacterium avium / Q000254:growth & development* / Q000302:isolation & purification; D012588:Scintillation Counting; D014316:Tritium
chemical_list: D014316:Tritium; D005990:Glycerol