Video Transcript
What type of immune cells secrete
antibodies? (A) Memory cells, (B) T-helper
cells, (C) macrophages, (D) neutrophils, or (E) plasma cells.
Antibodies, also called
immunoglobulins, are globular proteins which help the body to fight against a
pathogenic infection. They do that by binding to a
specific complementary antigen.
But how are antibodies
produced? Antibodies are involved in the
specific immune response. This immune response is often
divided into humoral and cell-mediated immunity. Humoral immunity relies on the
action of B cells and is most effective against extracellular pathogens. Cell-mediated immunity on the other
hand relies on the action of cytotoxic T cells and is effective against
intracellular pathogens. Both types of specific immunity
work simultaneously to fight infections.
Antibodies belong to the humoral
immunity, so let’s go through the processes of this immunity type. As mentioned, humoral immunity
relies on the action of B cells. Immature B cells have antibody
receptors, also called B receptors. These B cell receptors are
antibodies attached to the cell membrane of B cells. When the B cell receptor binds with
a complementary antigen, the B cell becomes activated itself. Note that B cells may also require
additional signaling from helper T cells to become activated.
Once the B cells are activated,
they begin to proliferate. This creates a population of B
cells that all possess B cell receptors that recognize a particular antigen. The mature activated B cells then
differentiate into one of two cell types. Some become memory B cells, which
live for a long time in the immune system, ready to rapidly activate if stimulated
by the same antigen in the future. The majority differentiate into
plasma cells. Plasma cells are B lymphocytes
that, instead of surface-bound antibody receptors, generate large quantities of
soluble antibodies that they secrete into the bloodstream and other body fluids.
This means that the type of immune
cells that secrete antibodies is given by answer choice (E), plasma cells.
