Plasma cells are those white blood cells that produce antibodies specific to that invading antigen. And these antibodies are released into our blood, our lymph, and our tissue. And when the antibodies bind onto that antigen, they label that antigen for destruction by other wide blood cells. And so that calls upon macrophages, natural killer cells, cytotoxic, T cells and many other different types of white blood cells to that area and that destroys that pathogen along with its antigen. Now, this is basically how our immune system defends and protects our body from these invading pathogens. Now, following our infection, our body develops something called active immunity.