Now, what about the T lymphocytes? So this dendritic cell can also interact with T lymphocytes. There are four different types of T lymphocytes. We have helper T cells, cytotoxic T cells, depressor T cells and memory T cells. So helper T cells are a very important type of lymphocyte because they assist many other cells with a differentiation process. Helper T cells help B lymphocytes differentiating the plasma cells and memory B cells and they also help tillyphasize themselves differentiate into cytotoxic T cells.