Figure 11.  The presence of IL4 during the later stages of NK cell development in vitro completely blocks the acquisition of CD94/NKG2 and Ly49 molecules, but has little effect on the expression of NKRP1 molecules

CD94

Ly49

NKRP1

IL2 alone

IL2 + IL4

Following primary culture of early thymic progenitors for 2 days in IL4+PMA, cells were

transferred to secondary cultures containing IL2 alone or IL2 + IL4, and stained 6 days later

with anti-CD94 mAb, the 4D12 anti-Ly49 mAb, PK136 anti-NKRP1C [NK1.1], or medium

[grey line on the NKRP1 graphs].

Conclusions

1.  Paradoxically, although IL4 is required in primary cultures for the efficient differentiation

of progenitor cells into NK cells, its continuing presence in IL2 containing secondary

cultures completely blocks the expression of CD94 and NKG2 [not shown] molecules

2.  By contrast, the continuing presence of IL4 has little effect on the expression of the NKRP1

molecules recognized by the anti-NK1.1 mAb PK136 [NKRP1C] or the 10A7 mAb [NKRP1B,

data not shown].

3.  Further studies showed that the CD94/NKG2 receptors acquired during 6 days culture in

IL2 alone were lost if cells were re-exposed to IL4 at that point.

4.  Even on established NK cell lines and clones the expression of CD94/NKG2 receptors

could be down-regulated by IL4 whereas the expression of the Ly49 molecules recognized by

4D12 and 14B11 mAbs was now resistant to IL4 down-regulation.