The present invention relates to a novel method for flow cytometric immunophenotyping of a mouse from a very small volume of blood using a novel combination of markers. The invention furthermore relates to a reagent composition for flow cytometric immunophenotyping of blood cells comprising fluorochrome-conjugated antibodies directed against a combination of markers.
1. A method for immunophenotyping of a mouse comprising the steps of: (i) providing a blood sample of the mouse, (ii) selecting a panel of fluorescently labeled antibodies, (iii) incubating the selected panel of fluorescently labeled antibodies with the blood sample to be tested, (iv) detecting the signal by flow cytometry to obtain detection data, and (v) determining the cell type according to the data obtained in step (iv), wherein the panel of fluorescently labeled antibodies comprises at least one of the following sets of markers: (a) CD45, Ly6C, B220, CCR2, CD11b, CD11c, CD172a, CD49b, CD80/CD86, F4/80, Ly6G, MHC-II, Siglec-F, or (b) CD45, CCR4, CCR6, CD138, CD19, CD25, CD3, CD4, CD44, CD62L, CD8, CXCR3, TNF-RII, NK1.1, wherein the volume of the blood sample of the mouse provided in (i) is less than 100 µl per set of markers. 2. The method of claim 1, wherein the selected panel comprises both sets of markers (a) and (b). 3. The method of claim 1 or 2, wherein the blood sample of the mouse provided in step (i) is less than about 80 µl, preferably less than about 70 µl, most preferred less than about 60 µl per set of markers. 4. The method of claim 1 or 2, wherein the blood sample of the mouse provided in step (i) is between about 50 to 100 µl per set of markers, most preferred is an amount of between about 50 to 80 µl per set of markers. 5. The method of any of the preceding claims, wherein the blood sample is a peripheral blood sample. 6. The method of any one of the preceding claims, wherein the step (v) determining the cell type according to the data obtained in step (iv) comprises simultaneously detecting more than 30, more preferably more than 40, most preferred more than 50 subpopulations of cells. 7. The method of any one the preceding claims, wherein the step (v) determining the cell type according to the data obtained in step (iv) comprises obtaining the total amount of cells of each subpopulation as an absolute value. 8. A reagent composition for the flow cytometric immunophenotyping of blood cells comprising fluorochrome-conjugated antibodies directed against at least one of the following sets of markers: (a) CD45, Ly6C, B220, CCR2, CD11b, CD11c, CD172a, CD49b, CD80, CD86, F4/80, Ly6G, MHC-II, Siglec-F, or (b) CD45, CCR4, CCR6, CD138, CD19, CD25, CD3, CD4, CD44, CD62L, CD8, CXCR3, TNF-RII, NK1.1. 9. The reagent composition of claim 8 or the method of any one of claims 1 to 8, wherein each antibody in the sets of markers (a) and (b) is conjugated to one of the following fluorochromes VioBlue, VioGreen, BV570, BV605, BV650, FITC, PE, ECD/PE-Vio615, PerCP/PE-Cy5/PC5, PerCP-Vio700/PC5.5, PE-Cy7/PE-Vio700/PC7, APC, AF700/APC5, APC-Fire<™> 750/APC7. 10. The reagent composition of claim 9 or the method of any one of claims 1 to 7, wherein each antibody in the sets of markers (a) and (b) is conjugated to a different fluorochrome.