B lymphocytes, antibodies, immunoglobulins, T lymphocytes, MHC, HLA.

The immune system consists of two main classes of cells: B lymphocytes and T lymphocytes. The effector B lymphocytes, plasma cells, are specialized for producing large amounts of a protein known as an antibody. Antibodies bind to specific antigens, leading to the destruction of the antigens and pathogens bearing the antigens. Immunoglobulins are just antibodies, categorized according to specific details of their structure and function. T lymphocytes are specialized for destroying cells that bear antigen within a self molecule known as MHC. MHC stands for major histocompatibility complex, which is a group of cell surface proteins essential for triggering the immune response. HLA stands for human leukocyte antigen, and is just an alternative name for MHC.