Study of Fc gamma murine macrophage receptors (Fc gamma R) in the internalization of Histoplasma capsulatum yeasts
Taylor, M.L.; Rico, B.; Goodsaid, F.
Archives of Medical Research 26(2): 179-184
1995
ISSN/ISBN: 0188-4409 PMID: 7620285 Document Number: 450770
Fungal cells were incubated with anti-Histoplasma murine IgG or normal IgG as control. The opsonized yeasts were adjusted and spread on a J774.2 macrophage cell line monolayer. Yeast cells were allowed to attach to the monolayers at 4 degrees C for 1 h prior to initiating the internalization step of the phagocytic process, by shifting the cells to 37 degrees C. The participation of Fc gamma R in the internalization of yeast was monitored by radio-iodination labelling of the macrophage surface proteins, and rosette-forming cells for erythrocytes coated with antibodies (RFC-EA). Results showed decreased [125I]-incorporation on the macrophage surface proteins at 15 min post-anti-Histoplasma IgG opsonized yeast infection. The same was observed when high and low virulence H. capsulatum strs. were used. A decrease of RFC percentage was also observed at 15 min after IgG opsonized yeast phagocytosis. The results supported the disappearance of Fc gamma R at 15 min from the surface of the macrophage that had ingested anti-Histoplasma IgG opsonized yeasts. The recovery of [125I]-counts and the RFC response at a longer time of phagocytosis indicated a possible Fe gamma R recycling mechanism.