Identification of subtypes of human DC and comparing them to mouse DC
The wealth of new knowledge on the mouse DC system has been difficult to translate to the human DC system. One problem is that most studies on human DC use blood as the available DC source, whereas most studies on mouse DC use lymphoid tissues such as spleen. Another problem is that many of the markers used for segregating mouse DC, such as CD8, are not expressed by human DC. Our solution is to directly compare DC from equivalent tissues, and we have began work on human spleen samples. In addition, our search for novel DC surface molecules has revealed many molecules that are common to mouse and human DC, and can be used as common markers of DC subtypes. An example is Clec9A, on the mouse CD8-bearing DC subtype, and apparently marking a similar DC subtype in humans. The human DC subtypes are being isolated and compared in function to the mouse DC subtypes.