Lymphocytes are part of the adaptive (specific) immune system, which monitors and dispatches in response to specific threats. The adaptive immune response utilizes antibody secretions from B-lymphocytes to target specific pathogens for elimination.

In contrast, the innate immune system is largely designed to prevent entry and propagation of non-specific pathogens. It is composed of barriers (such as skin and mucus linings) as well as non-specific immune cells (such as macrophages and natural killer cells).

The innate immune system is the part of your immune system that responds to threats almost immediately. It contains all the aspects which react to all threats and is generally seen as less complex than the adaptive immune system. The adaptive immune system includes aspects that respond to specific threats and develop memory to fight threats later on.

Each B-lymphocyte cell is responsible for creating one specific antibody. If the B-lymphocyte's antibody matches to the right antigen, the lymphocyte will differentiate into a plasma cell. Plasma cells release free antibodies into the bloodstream. The transition process from B-cell to plasma cell is mediated by helper T-cells.

Adaptive immunity involves immune cells created due to previously experiencing an infection by a particular pathogen. T-cell lymphocytes mature in the thymus, and recognize a specific antigen. T-cells and B-cells work to produce antibodies against a specific antigen, making them highly specific. This specification is only found in the adaptive immune system

In contrast, the innate immune system can respond to any pathogen, regardless of previous exposure, Neutrophils, monocytes, and macrophages are all part of the innate immune response and help with phagocytosis and inflammation.

Memory B-cells are long-lived descendents of B-cells that "remember" their encounter with an antigen and can rapidly respond to reexposure to the same antigen. Helper T-cells stimulate the immune responses by B-cells and cytotoxic T-cells. B-cells produce antibodies. Macrophages destroy invading microbes via phagocytosis and alert other immune cells to the invasion. Effector molecules include histamine and the cell-destroying proteins of cytotoxic T-cells. 

In response to infection, white blood cells multiply so that they can make antibodies against whatever it is your body is fighting off.

B-lymphocytes are the immune system's "memory"—once the body is attacked by a certain virus or bacteria, the body produces B-lymphocytes that can specifically recognize that disease. When the B-lymphocyte comes in contact with the disease (recognized by antibodies) it signals killer T-cells and helper T-cells to attack, and creates more antibodies to signal additional T-cells.

Natural killer cells destroy any cells of the human body that have become infected by an attacker. 

Macrophages are a general clean-up cell that sweep up debris, old cells, and sometimes attackers via phagocytosis.

Killer and helper T-cells are both activated by B-lymphocytes

B cells make antibodies that are specific to antigens. Antibodies bind to antigens to tag them for destruction. Cytotoxic T cells recognize and bind antigens and destroy them immediately. Helper T cells recognize antigens presented by antigen-presenting cells such as dendridic cells, and bring them to the attention of B cells, stimulating the B cells to begin making lots of antibodies.