title: Enhanced Fc receptor expression by a sub-population of murine intra-tumour macrophages following intravenous Corynebacterium parvum therapy.
abstract: Intravenous injection of Corynebacterium parvum (C. parvum) 4 days after s.c. inoculation of 5 X 10(5) cells derived from the immunogenic fibrosarcoma FSA/R induced tumour growth inhibition over a period of 21 days in syngeneic C3H/Buf mice. This was not accompanied by a change in the proportions of host cells within the tumour, but the activation state of tumour-infiltrating macrophages was increased following C. parvum therapy. Two macrophage subpopulations were identified in FSA/R tumours after fractionation by unit gravity velocity sedimentation. After i.v. C. parvum therapy the tumour-infiltrating macrophage subpopulation which sedimented between 1 and 6 mm h-1 was consistently activated as determined by measurement of Fc receptor avidity. Other intra-tumour macrophages were generally unaffected by C. parvum treatment. We have previously shown that the host cell fraction sedimenting between 1 and 6 mm h-1 is enriched with monocytes and the data presented in this paper suggest that these cells may enter the tumour in a pre-activated state following intravenous C. parvum therapy.
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000627:therapeutic use*; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D005354:Fibrosarcoma / Q000276:immunology* / Q000628:therapy; D008262:Macrophage Activation; D008264:Macrophages / Q000145:classification / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D011425:Propionibacterium acnes / Q000276:immunology*; D011961:Receptors, Fc / Q000032:analysis*; D012513:Sarcoma, Experimental / Q000276:immunology* / Q000628:therapy
chemical_list: D001428:Bacterial Vaccines; D011961:Receptors, Fc