2 Material and Methods
3.2 KIR expression pattern in primates
3.2.7 Expression of individual KIR by NK cells
An antibody with a broad KIR specificity (pan‐KIR) was used. (a) Dot plot examples of the analysed γδ T cell population of different animals using the pan‐KIR antibody. Gates for KIR positive cells were defined referring to the control without anti‐KIR antibody. (b) Comparison of the percentage and (c) mean fluorescence intensity (MFI) of all tested animals using 1C7.
3.2.7 Expression of individual KIR by NK cells
KIR3DL05 Expression
KIR3DL05 expression was analysed using 2H5‐DyLight633 antibody. Between 0.9 to 15.6 % of all NK cells did express this KIR in eight tested animals (Figure 19). The MFI of expressed KIR3DL05 varied between 167 and 662 for the tested animals. For some animals, there was only background signal detected with 2H5 (Bibbi, Gerdi, Kalle and Happy). Therefore, all eight animals were genotyped for KIR3DL05 and two out of eight (Gerdi and Happy) were KIR3DL05 negative. Transcript analysis showed KIR3DL05 mRNA expression for five animals (Kalle, King, Benno, Jogi and Franz) (Table 4). Clear surface expression was only observed for King and Benno (12.1 and 15.6 %). All other animals showed only low numbers of KIR3DL05 positive NK cells (less than 3 %).
Comparison with the total number of KIR‐positive NK cells (3.2.2) it is seen that not all KIR‐expressing NK cells did express KIR3DL05. Therefore, KIR3DL05 is expressed in a clonal pattern. In addition, the variance in the MFI of different animals showed differences in the amount of expressed KIR3DL05. No correlation between the
positive NK cells did not automatically have the highest amount of this KIR.
Furthermore, the presence of the gene or mRNA did not always lead to detectable cell surface expression of KIR3DL05 in these animals.
Figure 19. Flow cytometry analysis of expression of specific KIR by NK cells.
Three different antibodies were used. Shown is the number of KIR‐expressing NK cells (%, left panel) and the level of KIR expression (MFI, right panel) for KIR3DL05 (2H5), KIR3DLW03/KIR3DS05 (2H9), and KIR3DSW08/KIR3DS07/KIR3DL07 (2H3) (n=8 for 2H5 and n=7 for 2H9 and 2H3).
KIR3DLW03/KIR3DS05 Expression
The expression of KIR3DLW03/KIR3DS05 was observed for six out of seven animals using 2H9‐DyLight633 antibody (Franz was so far not analysed with this antibody). Jogi did not show any KIR3DLW03/KIR3DS05‐positive NK cells (Figure 19). The range of positive NK cells for the other animals was between 4.3 to 26.9 %, with a varying amount of KIR surface expression between animals (MFI 271‐2204) (Figure 19).
Genotyping identified KIR3DLW03/KIR3DS05 in all animals. Transcripts of KIR3DS05 were observed for all animals except Jogi and KIR3DLW03 mRNA was only found for Happy and Jogi (Table 4). Jogi did not show any surface expression of KIR3DLW03 and for Happy it was not possible to distinguish between KIR3DLW03 and KIR3DS05 expression using 2H9. For all other animals the detected expression was due to KIR3DS05 because of the absence of KIR3DLW03 transcripts. As for KIR3DL05, the expression pattern of KIR3DLW03/KIR3DS05 was observed to be clonal with a varying amount of KIR for different animals. No correlation between the two values was found (Pearson r=0.4069, p=0.4233).
Table 4. Summary of genotyping, transcript and protein surface expression of certain KIR for eight analysed rhesus macaques.
Shown are the data for the KIR genotyping, where + indicates the presence and – the absence of a gene. The transcript data were derived from 454 amplicon sequencing analysing cDNA from total mRNA of PBMCs (data provided by Christina Albrecht, Abteilung Primatengenetik, DPZ). The percentage of the total read number is shown. – indicates the absence of any transcript. Protein expression was analysed by three different antibodies (2H5, 2H9 and 2H3) labelled with DyLight633.
Shown are the percentage of positive cells and the MFI for NK cells, CD8+ αβ T cells and γδ T cells.
KIR3DS05 3.78 8.51 8.72 33.41 8.20 7.14 ‐ 18.10
mRNA (% of total reads)
KIR3DL07 ‐ 1.87 27.77 ‐ 11.00 10.45 21.76 2.30
NK cells 0.9/167 1.1/205 2.8/189 1.7/250 12.1/229 15.6/662 1.5/377 2.8/310 CD8+ T cells 0.7/62 0.6/122 1.3/85 1.8/140 4.1/42 2.7/267 1.7/264 0.8/267 2H5
γδ T cells 2.2/112 4.1/218 3.4/122 3.5/186 2.0/27 14.6/690 8.2/505 19.4/727 NK cells 7.3/271 11.6/359 4.3/283 18.9/860 26.9/925 11.2/2204 0.8/330 ‐ CD8+ T cells 0.8/118 1.7/110 1.3/139 4.4/196 4.9/217 0.6/127 1.7/275 ‐ 2H9
γδ T cells 2.7/182 13.8/476 2.7/215 10.4/331 34.1/1575 1.9/167 7.7/528 ‐ NK cells 2.2/163 3.7/233 9.2/416 55.9/1725 31.4/1525 20.9/1677 7.2/546 ‐ CD8+ T cells 1.2/118 2.9/158 5.2/233 11.1/372 5.98/289 2.7/244 16.2/688 ‐
Protein (%/mean) 2H3
γδ T cells 4.9/245 17.5/665 6.8/317 14.8/559 35.9/1863 17.7/625 26.1/1155 ‐
KIR3DSW08/KIR3DS07/KIR3DL07 Expression
The expression of these KIRs was analysed for seven animals (all except Franz) and observed for 2.2‐55.9 % of all NK cells with a varying amount (MFI 163‐1725) using 2H3‐DyLight633 (Figure 19).
The KIR3DS07 gene was detected in genomic DNA of Happy, King, Benno, Franz, and Jogi but no mRNA of this KIR gene was observed for any of the animals (Table 4). The
KIR3DL07 was negative for Bibbi, King, and Benno, respective mRNA was detected (Table 4). The DNA genotyping might miss the detection of certain KIR3DL07 alleles;
therefore, this method needs to be optimised. Happy, the animal with the most positive NK cells for KIRs as measured with 2H3 (Figure 19), did not show transcripts for any of the three analysed KIRs (Table 4). Therefore, either the amplicon sequencing needs to be improved, or 2H3 might detect KIR proteins that are not known or not covered by any of the methods applied here. In those cases where the specific gene was typed as
“present” and mRNA was not detected, the respective KIR is either not expressed or only on very low levels that preclude detection by 454 amplicon sequencing. This might be the case for the KIR3DSW08 gene, which is obviously present in all animals analysed, but only Jogi showed KIR3DSW08 transcripts (Table 4).
For the expression of the KIR molecules detected by 2H3 a significant correlation of the frequency of KIR3DSW08/KIR3DS07/KIR3DL07 positive NK cells and the amount of expressed KIR was observed (Pearson r=0.8468, p=0.0334).
3.2.8 Expression of individual KIR by different T cell subsets
Different T cell subsets were also analysed for their expression of individual KIR using the antibodies 2H5, 2H9, and 2H3. All CD8+ αβ and γδ T cells were characterised for their expression of KIR3DL05, KIR3DLW03/KIR3DS05 and KIR3DSW08/KIR3DS07/KIR3DL07, respectively. The animals included in this analysis were the same as for the NK cells in the chapter before.
KIR3DL05 is expressed by 0.5‐4 % of CD8+ αβ T cells and by 2‐20 % of γδ T cells (Figure 20). 1.5‐16 % of all CD8+ αβ T cells were positive for KIR3DSW08/KIR3DS07/
KIR3DL07 with the 2H3 antibody and 5‐37 % of the γδ T cells. KIR3DLW03/KIR3DS05 was detected on 0.3‐5 % of CD8+ αβ T cells and on 2‐35 % of γδ T cells using the 2H9 antibody. Comparison of the detected percentages for certain KIRs with the total KIR expression of both CD8+ αβ and γδ T cells (3.2.4, 3.2.6) showed similar to NK cells a clonal expression pattern of certain KIRs for these cell subsets. Furthermore, the amount of expressed KIRs differs between animals.