[limonade]

I know the  B cells use class II MHC proteins to present antigens, but they also contain MHC I proteins. What is the function of MHC I in these  B  immune system cells?

Thanks in advance

Evolutionary carryover? Usage of MHC I for recognition by cytotoxic T cells in case the B cells are somehow dysfunctional and need to be destroyed?

[Babcock_Hall]

I am not an expert in the immune system, but my understanding is that all cells have MHC I proteins.  My understanding is that class I and class II present peptides from different sources.  Class I peptides derive from (mainly?) cytoplasm, and Class II peptides derive from (mainly?) extracellular sources:  http://www.cryst.bbk.ac.uk/pps97/assignments/projects/coadwell/MHCSTFU1.HTM