Monocytes

Monocytes are the largest type of leukocyte and are involved in immune responses to bacteria, viruses, and fungi. They can differentiate both into macrophages that can penetrate into tissues and perform defense functions, or into myeloid lineage dendritic cells to effect an immune response. There are at least three subclasses of monocytes in human blood based on their phenotypic receptors.

In the Blood Atlas we have 189 cell lineage enriched genes and 27 of these genes has the highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed. In addition, 762 genes are cell lineage group enriched and an additional 11 genes are enhanced in this cell lineage. Altogether, 962 genes are elevated and among these 213 also show highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed.

Figure 1. The distribution of all genes across the five specificity categories based on transcript abundance in monocyte celll lineage as well as in the other 5 cell lineages

Table 1. Number of genes in the subdivided categories of elevated expression in monocyte cell lineage.

Table 2. The genes with the highest level of enriched expression in monocyte cell lineage. "pTPM" shows the transcript level as protein-coding transcripts per million. Specificity-score corresponds to the score calculated as the fold change of monocyte cell lineage expression to the second highest cell lineage.

Classical monocytes

The classical monocyte is characterized by high level expression of the CD14 cell surface receptor (CD14++ CD16− monocyte).

In the Blood Atlas we have 18 classical monocyte enriched genes and 1 of these genes has the highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed. In addition, 353 genes are cell type group enriched and an additional 125 genes are enhanced in this cell type. Altogether, 496 genes are elevated and among these 104 also show highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed.

The classical monocytes were isolated from PBMCs. Debris, cell aggregates and most of lymphocytes were eliminated based on scatter profiles. The remaining NK, T- and B-cells were eliminated by selecting CD3neg/CD19neg/CD20neg/CD56neg cells. The classical monocytes were sorted as CD14+/CD16neg cells and 50,000 – 190,000 cells were sorted per sample for transcriptomic analysis by mRNA-sequencing. The transcriptome analysis shows that 52% (n=10180) of all human proteins (n=19,670) are expressed in the classical monocytes and 353 of these genes show an elevated expression in classical monocytes compared to the other 17 cell types (see figure below).

Figure 2. The distribution of all genes across the five specificity categories based on transcript abundance in classical monocyte cells as well as in the other 17 cell types.

Table 3. Number of genes in the subdivided categories of elevated expression in classical monocyte cells.

Table 4. The genes with the highest level of enriched expression in classical monocyte cells. "pTPM" shows the transcript level as protein-coding transcripts per million. Specificity-score corresponds to the score calculated as the fold change of classical monocyte cellsexpression to the second highest cell type.

Non-classical monocytes

The non-classical monocyte shows low level expression of CD14 and additional co-expression of the CD16 receptor (CD14+CD16++ monocyte).

In the Blood Atlas we have 35 non-classical monocyte enriched genes and 2 of these genes has the highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed. In addition, 300 genes are cell type group enriched and an additional 163 genes are enhanced in this cell type. Altogether, 498 genes are elevated and among these 108 also show highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed.

The non-classical monocytes were isolated from PBMCs. Debris, cell aggregates and most of lymphocytes were eliminated based on scatter profiles. The remaining NK, T- and B-cells were eliminated by selecting CD3neg/CD19neg/CD20neg/CD56neg cells. The non-classical monocytes were sorted as CD14low/CD16+ cells and 1,000 – 26,000 cells were sorted per sample for transcriptomic analysis by mRNA-sequencing. The transcriptome analysis shows that 49% (n=9720) of all human proteins (n=19,670) are expressed in the non-classical monocytes and 300 of these genes show an elevated expression in non-classical monocytes compared to the other 17 cell types (see figure below).

Figure 3. The distribution of all genes across the five specificity categories based on transcript abundance in non-classical monocyte cells as well as in the other 17 cell types.

Table 5. Number of genes in the subdivided categories of elevated expression in non-classical monocyte cells.

Table 6. The genes with the highest level of enriched expression in non-classical monocyte cells. "pTPM" shows the transcript level as protein-coding transcripts per million. Specificity-score corresponds to the score calculated as the fold change of non-classical monocyte cell expression to the second highest cell type.

Intermediate monocytes

The intermediate monocyte has high level expression of CD14 and low level expression of CD16 (CD14++CD16+ monocytes).

In the Blood Atlas we have 15 intermediate monocyte enriched genes and 4 of these genes has the highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed. In addition, 360 genes are cell type group enriched and an additional 142 genes are enhanced in this cell type. Altogether, 517 genes are elevated and among these 117 also show highest expression in blood or lymphoid tissues when comparing all tissues and organs analysed.

The intermediate monocytes were isolated from PBMCs. Debris, cell aggregates and most of lymphocytes were eliminated based on scatter profiles. The remaining NK, T- and B-cells were eliminated by selecting CD3neg/CD19neg/CD20neg/CD56neg cells. The intermediate monocytes were sorted as CD14+/CD16+ cells and 2,000 – 5,000 cells were sorted per sample for transcriptomic analysis by mRNA-sequencing. The transcriptome analysis shows that 51% (n=9980) of all human proteins (n=19,670) are expressed in the intermediate monocytes and 360 of these genes show an elevated expression in intermediate monocytes compared to the other 17 cell types (see figure below).

Figure 4. The distribution of all genes across the five specificity categories based on transcript abundance in intermediate monocyte cells as well as in the other 17 cell types.

Table 7. Number of genes in the subdivided categories of elevated expression in intermediate monocyte cell.

Table 8. The genes with the highest level of enriched expression in intermediate monocyte cell. "pTPM" shows the transcript level as protein-coding transcripts per million. Specificity-score corresponds to the score calculated as the fold change of intermediate monocyte cell expression to the second highest cell type.