Answer:
Step-by-step explanation:
The primary immune response involves several steps when an invader that the body hasn't yet encountered enters body tissue. Here's an explanation of the key steps in the primary immune response:
1) Recognition: Specialized cells of the immune system, such as macrophages and dendritic cells, recognize the presence of the invader, known as an antigen. These cells engulf the antigen and process it into smaller fragments for presentation.
2) Antigen Presentation: The processed antigen fragments are displayed on the surface of the antigen-presenting cells (APCs) to activate other immune cells. This presentation helps alert the immune system to the presence of the invader.
3) Activation of Helper T cells: The displayed antigen fragments bind to specific receptors on helper T cells. This interaction stimulates the activation of helper T cells, triggering their division and differentiation into effector cells.
4) Activation of B cells: Some helper T cells activate B cells, which produce antibodies. The activation of B cells occurs when their specific surface receptors bind to the antigen or when helper T cells provide signals.
5) Antibody Production: Activated B cells differentiate into plasma cells, which produce and release large amounts of antibodies. Antibodies are proteins that specifically recognize and bind to the antigen, marking it for destruction.
6) Destruction of Invader: Antibodies bind to the antigen on the surface of the invader, neutralizing it and facilitating its elimination. Antibodies can also activate other immune cells, such as macrophages and natural killer cells, to destroy the invader directly.
7) Memory Cell Formation: During the primary immune response, some activated B and T cells differentiate into memory cells. These memory cells persist in the body and provide long-term immunity. If the same invader enters the body again, memory cells can quickly recognize and mount a faster and more efficient immune response, known as the secondary immune response.
Overall, the primary immune response involves the recognition of the invader, antigen presentation, activation of helper T cells and B cells, antibody production, destruction of the invader, and the formation of memory cells. This response helps the body eliminate the invader and establishes long-term immunity against future encounters.