Chapter 21 - Section 21.5 - Humoral Immunity - Before You Go On - Page 837: 21

B cells and plasma cells are both types of immune cells involved in the adaptive immune response, specifically in humoral immunity. While they share a common lineage, they have distinct functions and characteristics. Here's the difference between B cells and plasma cells: **B Cells:** 1. **Maturation and Activation:** B cells develop and mature in the bone marrow. Upon encountering an antigen that matches their B cell receptors (BCRs), they become activated. 2. **Antigen Recognition:** B cells express BCRs on their surface, which are membrane-bound antibodies that can bind to specific antigens. BCRs are unique to each B cell and determine the B cell's antigen specificity. 3. **Functions:** Activated B cells can differentiate into two main types of cells: plasma cells and memory B cells. 4. **Plasma Cell Differentiation:** In response to an antigen, some activated B cells differentiate into plasma cells. This differentiation involves the expansion of the endoplasmic reticulum and increased production of antibodies. **Plasma Cells:** 1. **Function:** Plasma cells are specialized antibody-producing cells. They secrete large amounts of antibodies (also known as immunoglobulins) into the bloodstream and body fluids. 2. **Antibody Production:** Plasma cells produce and release antibodies that are specific to the antigen recognized by the original B cell. These antibodies have the same antigen-binding specificity as the BCRs of the parent B cell. 3. **Short Lifespan:** Plasma cells have a relatively short lifespan and are considered terminally differentiated. They are highly specialized for antibody production. 4. **Immune Response:** The antibodies produced by plasma cells circulate in the bloodstream and body fluids, where they can neutralize pathogens, opsonize them for phagocytosis, or activate complement proteins to promote pathogen destruction. In summary, B cells are immune cells that can differentiate into plasma cells among other types, while plasma cells are specialized cells that produce and secrete antibodies. B cells play a role in recognizing antigens through their BCRs, while plasma cells play a central role in the production of antibodies that contribute to the immune response against infections and other threats.

B cells and plasma cells are both types of immune cells involved in the adaptive immune response, specifically in humoral immunity. While they share a common lineage, they have distinct functions and characteristics. Here's the difference between B cells and plasma cells: **B Cells:** 1. **Maturation and Activation:** B cells develop and mature in the bone marrow. Upon encountering an antigen that matches their B cell receptors (BCRs), they become activated. 2. **Antigen Recognition:** B cells express BCRs on their surface, which are membrane-bound antibodies that can bind to specific antigens. BCRs are unique to each B cell and determine the B cell's antigen specificity. 3. **Functions:** Activated B cells can differentiate into two main types of cells: plasma cells and memory B cells. 4. **Plasma Cell Differentiation:** In response to an antigen, some activated B cells differentiate into plasma cells. This differentiation involves the expansion of the endoplasmic reticulum and increased production of antibodies. **Plasma Cells:** 1. **Function:** Plasma cells are specialized antibody-producing cells. They secrete large amounts of antibodies (also known as immunoglobulins) into the bloodstream and body fluids. 2. **Antibody Production:** Plasma cells produce and release antibodies that are specific to the antigen recognized by the original B cell. These antibodies have the same antigen-binding specificity as the BCRs of the parent B cell. 3. **Short Lifespan:** Plasma cells have a relatively short lifespan and are considered terminally differentiated. They are highly specialized for antibody production. 4. **Immune Response:** The antibodies produced by plasma cells circulate in the bloodstream and body fluids, where they can neutralize pathogens, opsonize them for phagocytosis, or activate complement proteins to promote pathogen destruction. In summary, B cells are immune cells that can differentiate into plasma cells among other types, while plasma cells are specialized cells that produce and secrete antibodies. B cells play a role in recognizing antigens through their BCRs, while plasma cells play a central role in the production of antibodies that contribute to the immune response against infections and other threats.