To distinguish between two possible functions of CD8a+ dendritic cells, first function is that CD8a+ needed for the cross-presentation of antigens and then to be presented to the MHC I; and the second...

To distinguish between two possible functions of CD8a+ dendritic cells,


_{first function
is that CD8a+ needed for the cross-presentation of antigens and then to be presented to the MHC I; and the
second function
is that the viral antigens are brought to the draining lymph nodes with the help CD8a+ dendritic cells.}
a set of wild-type and
Batf3^-/-

mice are immunized with 100 PFU of WNV in the left footpad. At day 7 post-infection, the left popliteal LN are isolated from the mice, and the CD4 T cells in these LN populations are tested for responses to a WNV peptide bound to MHC class II (peptide Y). As a negative control, an MHC class II-binding peptide from ova is used. These results are shown in the figure below.  Do these results rule in/out either of the two possible functions of CD8a+ dendritic cells indicated at the begining of this paragraph? Why or why not?