But we have a pretty good idea. Well, since these T cells do not actually bind onto the MHC class one or the MHC class two regions of these antigen presenting cells such as macrophages dendritic cells and B lymphocytes, that implies that gamma delta T cells do not actually depend on these antigen presenting cells to carry out their immune defensive response. So, although their function and mechanism of action is still not very well understood, they are believed to be part of the first line of defense and team to react faster at a quicker rate than our AlphaBeta T cells do. In fact, these gamma delta T cells are believed to be involved with immuno surveillance. And what that means is basically swimming around the epithelial tissue of our body and making sure that everything is working correctly and no pathogen is found inside those regions of the body. So we see that the antigens to which these gamma delta T cells actually bind to are not only found on the actual pathogen, for example, our bacterial cell, but they are also found on infected cells of our body.