Effektorcellerna

Effektorcellerna are a crucial component of the adaptive immune system in vertebrates. They represent the final effector stage of lymphocyte differentiation, specifically T cells and B cells. Following activation by antigens and appropriate co-stimulatory signals, naive T and B cells undergo proliferation and differentiation into effector cells. These effector cells are specialized for eliminating pathogens or infected cells.

Effector T cells include cytotoxic T lymphocytes (CTLs) and helper T cells. CTLs directly kill target cells, such as virus-infected cells or tumor cells, through mechanisms like releasing perforin and granzymes. Helper T cells, such as Th1 and Th2 cells, do not directly kill but instead orchestrate the immune response. Th1 cells enhance cell-mediated immunity, while Th2 cells promote humoral immunity by activating B cells.

Effector B cells, also known as plasma cells, are primarily responsible for antibody production. Once activated, B cells differentiate into plasma cells that secrete large quantities of antibodies specific to the encountered antigen. These antibodies can neutralize pathogens, opsonize them for phagocytosis, or activate complement pathways.

The differentiation into effector cells is a transient state. Once the threat is cleared, most effector cells undergo apoptosis. However, a subset of these cells will survive and persist as memory cells, providing long-term immunity against future encounters with the same pathogen. This memory population is key to the efficacy of vaccination and secondary immune responses.