CD4⁺ TSCMs in the Bone Marrow Assist in Maturation of Antibodies against Influenza in Mice

Figure 4

CD4⁺ TSCMs attach to VCAM-1⁺ IL-15- and IL-7-expressing stromal cells. (a) Colocalizations of CD4⁺ TSCMs with VCAM-1⁺ IL-15- and IL-7-expressing stromal cells. The 1 × 10⁶ CD4⁺ TSCMs isolated from the BM were labeled with CMTPX (red) and then injected to CD45.1 mice. After 24 h, the recipients were sacrificed and bone tissues were conducted for immunofluorescence staining. The immunofluorescence images show a representative picture of anti-VCAM-1 (green), IL-15 (green), CXCL-12 (green), or IL-7 (green) versus CMTPX-labeled TSCMs (red). The scale bars indicate that the actual distances on the specimen are 50 μm. Data are representative of three independent experiments. (b) Colocalizations of TSCMs with VCAM-1⁺ PDGFRβ⁺ CD31⁻ Sca-1⁻ cells. The 5 × 10⁵ TSCMs sorted from the C57B6/J mice BM were labeled with CMTPX (red, 5 μM) and mixed with 1 × 10⁶ VCAM-1⁺ PDGFRβ⁺ CD31⁻ Sca-1⁻ cells (from the BM) labeled with CFSE (green, 10 μM). Cells were injected into CD45.1 mice. After 24 h, the recipients were sacrificed and conducted frozen sections. The photo shows a representative picture of CFSE-staining VCAM-1⁺ PDGFRβ⁺ CD31⁻ Sca-1⁻ cells (CXCL-12-abundant reticular cells, CAR cells) versus CMTPX-labeled TSCMs. The scale bar indicates that the actual distance on the specimen is 50 μm. (c) Flow cytometric analysis of VCAM-1⁺ PDGFRβ⁺ CD31⁻ Sca-1⁻ cells in the SP and BM. Dot plots represent the frequencies of VCAM-1⁺ PDGFRβ⁺ cells (left) and CD31⁻ Sca-1⁻ cells (right) in the SP and BM. Data are representative for three independent experiments (). Frequencies of VCAM-1⁺ PDGFRβ⁺ CD31⁻ Sca-1⁻ cells were shown as means ± SD, -test. , , and .

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