Final answer:
The body's last-ditch defense mechanism is the cell-mediated immune response, which involves cytotoxic T cells attacking infected or cancerous cells, and is a part of the adaptive immune system.
Step-by-step explanation:
Your body's last-ditch effort to defend itself is your cell-mediated immune response.
The cell-mediated immune response is a critical component of the adaptive immune system, particularly when it comes to defending the body against viruses that have infected cells and cancers. This response is primarily controlled by T cells, which are types of white blood cells. There are several types of T cells, including helper T cells (TH), cytotoxic T cells (Tc), and regulatory T cells (Treg). Cytotoxic T cells are especially vital as they directly attack and destroy infected cells.
The adaptive immune response also includes B cells that differentiate into plasma cells, which produce antibodies. However, when these initial defenses fail to eliminate pathogens or abnormal cancer cells, the Tc cells step in as a last-ditch effort to protect the body. They specifically target and destroy the compromised cells, preventing the spread of infection or the growth of tumors. Memory T cells are also created during this process, which ensures a faster and more efficient response if the pathogen is encountered again.