Microbiology Practice Exam

Which of the following processes occurs after the binding of an antigen to a B-cell?

1. Clonal selection

2. Phagocytosis

3. Apoptosis

4. Antigen presentation

The correct answer is: Clonal selection

The process that occurs after the binding of an antigen to a B-cell is clonal selection. When a B-cell encounters its specific antigen, the binding of the antigen to the B-cell receptor (which is a membrane-bound immunoglobulin) triggers activation of the B-cell. This activation leads to proliferation and differentiation of the B-cell into a clone of cells that can produce antibodies specific to that antigen. Clonal selection ensures that only the B-cells capable of recognizing and responding to a specific antigen are activated and cloned, which is a crucial step in the adaptive immune response. This process allows the immune system to generate a tailored response to the invading pathogen by producing large quantities of antibodies that target the specific antigens present. Other processes mentioned, such as phagocytosis, apoptosis, and antigen presentation, play roles in the immune response but occur within different contexts or following different signaling events. Phagocytosis is primarily associated with immune cells like macrophages and neutrophils that engulf pathogens. Apoptosis refers to programmed cell death and is not a direct result of antigen binding in B cells. Antigen presentation typically involves the display of processed antigens on major histocompatibility complex (MHC) molecules by antigen-presenting cells (AP