Objective To observe the expression characteristics of green fluorescent protein(GFP)-positive myeloid cells(mainly monocytes,macrophages,and neutrophils)and their pattern of response to diphtheria toxin(DT)in Lyz2 internal ribosome entry site(IRES)DT receptor/enhanced GFP(DTREGFP)mice.Methods Transgenic Lyz2 IRES DTREGFP mice(6～8 weeks old)and C57BL/6J mice with the same genetic background were selected randomly and injected intraperitoneally with DT(25 ng/g)for 3 consecutive days.Bone marrow,peripheral blood,and spleen cells were separated and made into single-cell suspensions with GFP and CD11b as markers.Changes in the proportion of GFP+cells to total myeloid cells(CD11b+)was detected in these tissues at different time points before and after drug administration,using flow cytometry.Results Peripheral blood CD11b+GFP+cells accounted for(24.62±5.655)％of CD11b+cells before DT injection,and this proportion gradually decreased after injection and reached a minimum of(7.982±2.729)％on the third day.The proportions in spleen and bone marrow were(13.73±2.994)％and(65.23±4.261)％before DT injection,respectively,decreased most significantly on the first day after injection to(3.468±0.5862)％and(50.98±7.957)％,respectively,and then gradually recovered.Conclusions DT effectively reduced the proportions of monocytes,macrophages,and neutrophils in Lyz2 IRES DTREGFP mice,but the pattern of change varied among tissues.

Objective To observe the expression characteristics of green fluorescent protein(GFP)-positive myeloid cells(mainly monocytes,macrophages,and neutrophils)and their pattern of response to diphtheria toxin(DT)in Lyz2 internal ribosome entry site(IRES)DT receptor/enhanced GFP(DTREGFP)mice.Methods Transgenic Lyz2 IRES DTREGFP mice(6～8 weeks old)and C57BL/6J mice with the same genetic background were selected randomly and injected intraperitoneally with DT(25 ng/g)for 3 consecutive days.Bone marrow,peripheral blood,and spleen cells were separated and made into single-cell suspensions with GFP and CD11b as markers.Changes in the proportion of GFP+cells to total myeloid cells(CD11b+)was detected in these tissues at different time points before and after drug administration,using flow cytometry.Results Peripheral blood CD11b+GFP+cells accounted for(24.62±5.655)％of CD11b+cells before DT injection,and this proportion gradually decreased after injection and reached a minimum of(7.982±2.729)％on the third day.The proportions in spleen and bone marrow were(13.73±2.994)％and(65.23±4.261)％before DT injection,respectively,decreased most significantly on the first day after injection to(3.468±0.5862)％and(50.98±7.957)％,respectively,and then gradually recovered.Conclusions DT effectively reduced the proportions of monocytes,macrophages,and neutrophils in Lyz2 IRES DTREGFP mice,but the pattern of change varied among tissues.