MHC presentation is a house keeping process. it seems that you can not control MHC to present just only one kind of peptide you want. But you can still feed the APC with your desired peptide for a period of time, and these APC could  predominantly present your specific peptide.

You can use the T2 or P815 cell lines to capture and present a peptide of interest.

Similarly, certain populations of dendritic cells, notably from CD34 + GM / TNF, can be used to present the selected peptide. But, if it is more efficient, it is also more delicate because some of these DCs will inevitably process the peptide after having captured it.

Otherwise you can increase the size of your peptide. This one will be captured by the DCs, then processed and finally presented on the surface of the DC. And if you're lucky you'll have two peptides presented: one for T cells and one for B cells, the perfect trilogy

I once wanted to load most MHC class II molecules on a cell with peptides from a single protein. But, I could not afford to buy enough of the antigen protein to get good loading.... So I made the antigen presenting cell produce the antigen for me. I did this by forcing an MHC class II positive B cell line to express the antigen protein on the cell surface by stable transfection. (I had to add a transmembrane domain and connecting stalk to the antigen protein).  The protein was produced, processed into peptides, and then presented on MHC class II by the B cell. In fact, most of the MHC class II on the B cell was loaded with peptides from the protein antigen. (see Proc Natl Acad Sci U S A. 1997 Jan 21;94(2):628-33).