CD4 and infection: Therefore, using mass cytometry, we simultaneously investigated the expression of 17 characteristic cell surface markers (CD3, CD4, CD8, CD11a, CD11b, CD11c, CD14, CD16, CD19, CD32, CD64, CD66, CD86, CD123, CCR5, CXCR4, and HLA-DR) in leukocytes of healthy persons and HIV-ART patients after ex vivo infection of whole blood with MVA (Figure 2).