Final answer:
The cell-mediated immune response is a vital part of the immune system's ability to target and eliminate intracellular pathogens, abnormal body cells, such as those found in cancers, and respond to specific endogenous antigens. The final answer, encompassing all these aspects, is 'd. all of the above'.
Step-by-step explanation:
The body mounts a cell-mediated immune response for a variety of reasons, each unique to the pathogenic challenge it encounters. This response is essential for targeting and eliminating not just pathogens that have infected cells but also for engaging with and destroying abnormal or rogue cells within the body, such as cancer cells.
a. To fight intracellular pathogens: Once a pathogen has entered a cell, it is often shielded from humoral immunity, which consists of antibodies circulating freely in the body. The cell-mediated response, however, utilizes T lymphocytes, which can recognize infected cells and initiate their destruction.
b. To fight abnormal body cells: Sometimes, cells within the body become abnormal, as is the case with cancer. These abnormal cells may present different antigens on their surface that are recognized by the immune system, prompting a targeted attack by T cells.
c. In response to specific endogenous antigens: A cell-mediated response can also be provoked by antigens that are internal and not associated with a foreign pathogen. This includes the presentation of self-antigens in a non-physiological context, as seen in autoimmune diseases.d. all of the above. This is because the cell-mediated immune response is multifaceted, dealing with intracellular pathogens, abnormal body cells, and specific endogenous antigens that may pose a threat to the body's integrity and health.