Phagocytes are big cells responsible for the innate immunity: they are the first line of defence of the body, and act "by eating" the foreign bodies: for example, a bacterium will be recognized by the phagocyte, incorporated ,and split up.
Their cytoplasm is constituted by pseudopodes which allow to surround the bacterium.
The second type of immunity is said "acquired", or "adaptive". it is due to the action of lymphocytes, which have a much more specific action than the phagocytes: they recognize specifically a molecular motive. When they are at the contact of this one, they are going to divide themselves a large number of time to increase their efficiency. Lymphocytes B are going to produce antibodies, T CD4 is going to facilitate the production of LB and the LT CD8. The LT CD8 are going to kill cells infected (by a cytotoxic action).
The lymphocyte NK (natural killer) are going to eliminate of the tumoral cells.