OSMT (Ontario Society of Medical Technologists) Practice Exam

Which lymphocyte stimulates activity in antigen encounters?

1. Memory cell

2. Killer T cell

3. Helper T cell

4. Suppressor T cell

The correct answer is: Helper T cell

The Helper T cell plays a critical role in the adaptive immune response by stimulating and enhancing the activity of other immune cells during antigen encounters. Upon recognizing antigens presented by antigen-presenting cells, Helper T cells release cytokines that serve as signals to activate and proliferate other lymphocytes, such as B cells and cytotoxic (Killer) T cells. This activation is essential for orchestrating a coordinated immune response, allowing the body to effectively combat pathogens. Memory cells, on the other hand, are specifically involved in the long-term immunity following an initial response, enabling a quicker and stronger response upon re-encountering the same antigen. Killer T cells are responsible for directly attacking and destroying infected cells but are not responsible for stimulating the activity of other immune cells. Suppressor T cells function to regulate and down-modulate immune responses to prevent overactivity, which helps maintain immune tolerance and prevent autoimmune reactions. Their role is more about tempering the immune response rather than stimulating activity.