The ordinary system:
The bone marrow makes millions of kinds of antibody producing immune-cells.
Each cell-type goes to immunological organs where they are waiting for its special infection that will trigger growth of clones from its few innate primed cells.
Within a few days after having been attacked by a new intruder the immune cells producing the actual antibodies will start growing until reaching a high number of cells necessary for combating the infection.
Discovery of an assumed special immune system:
2. Small local amounts of virus in the body after exposure or small local amounts after a viral disease are inactivated or killed.
3. Small local numbers of tumor cells transplanted, or small local numbers of spontaneously developed tumor cells left behind after anti-tumor treatment, or locally a few spontaneously and recently created tumor cells are inactivated or killed.