Natural killer cells, B cells, and cytotoxic T lymphocytes (NK cells, B cells, and CTLs)

Natural killer (NK) cells, B cells, and cytotoxic T lymphocytes (CTLs) are essential components of the human immune system, providing both innate and adaptive defense mechanisms. NK cells are innate lymphoid cells that identify and destroy virally infected or tumor cells through the release of perforins and granzymes without prior sensitization (StatPearls, 2023). B cells are the mediators of humoral immunity, differentiating into plasma cells that secrete highly specific antibodies to neutralize pathogens (NIH, 2022). Cytotoxic T lymphocytes (CTLs), typically characterized by the expression of CD8, recognize specific antigens presented by MHC class I molecules and execute targeted cell death (PubMed, 2021). While these are distinct cell populations rather than single molecular targets, they are the primary effectors or targets of many modern immunotherapies, such as checkpoint inhibitors (e.g., Pembrolizumab) and B-cell depleting agents (e.g., Rituximab) (FDA, 2023). Therapeutic strategies often aim to enhance the activity of CTLs and NK cells against cancer or suppress B-cell activity in autoimmune conditions.

Other names

LymphocytesImmune effector cellsWhite blood cells

Therapeutic agents interact with these cells by targeting specific surface antigens (e.g., CD20, CD19) or checkpoint receptors (e.g., PD-1) to either deplete the cell population, stimulate effector functions, or release inhibitory signals.