Lymph nodes and spleen have the best expression.

https://www.proteinatlas.org/ENSG00000102245-CD40LG/tissue

The following are mouse and human cell lines expressing CD40L. I am unsure whether they express the transmembrane or the soluble form though.

https://www.kerafast.com/product/2291/cd40l-expressing-feeder-cell-line-el-4-b5

http://bpsbioscience.com/cd40-hek293-cell-line-71257

If you just need a recombinant CD40L trimer, I have had success stimulating B cells using Mega-CD40L

http://www.enzolifesciences.com/ALX-522-120/megacd40l-soluble-mouse-recombinant/

http://www.enzolifesciences.com/ALX-522-110/megacd40l-soluble-human-recombinant/

Hi Michael and Julie,

That's very helpful, thank you so much.

I'll appreciate more input from the community on murine cell lines that might be expressing CD40L.

David