Question

Neutrophils can sometimes kill human cells along with pathogens when they release the toxic contents of their granules into the surrounding tissue. Likewise, natural killer cells target human cells for destruction. Explain why it is advantageous for the immune system to have cells that can kill human cells as well as pathogens.

Answer 1

The immune system's ability to destroy human cells, through mechanisms involving neutrophils and natural killer cells, is essential for removing malfunctioning, infected, or cancerous cells, thereby protecting the body's health.

The immune system has mechanisms to target and kill human cells as well as pathogens. Neutrophils and natural killer cells play crucial roles in this process. Neutrophils, being highly active phagocytes, can sometimes destroy human cells inadvertently when releasing toxic granules aimed at pathogens. Similarly, natural killer cells target and induce apoptosis in human cells that are infected or cancerous. This ability to kill both pathogenic and human cells is critical because it ensures the removal of cells that are malfunctioning or pose a risk to the body's overall health, such as cancerous or virus-infected cells.

Natural killer cells are particularly important as a line of defense, recognizing cells with significantly low levels of MHC proteins—which could indicate infection or malignant transformation—and prompting those cells to undergo apoptosis. Afterward, phagocytic cells clear the cellular debris.

the capacity to destroy human cells when necessary is advantageous for maintaining the health and integrity of the organism by eliminating potential threats from within.

Answer 2

Because Neutrophils has many other functions like

• Neutrophils are the most abundant granulocytes that makeup about 40% of white blood cells and 60% of the immune cells in the blood.
• Neutrophils are the first responders to infection, and they phagocytose bacteria into phagosomes before hydrolyzing and destroying them.
• These cells also secrete a range of proteins that have antimicrobial effects as well as tissue remodeling potential.
• Neutrophils have a short lifespan and thus destroy themselves during the degradation of foreign invaders. New neutrophils are then produced continuously in the bone marrow.
• The neutrophils of another subpopulation, cager neutrophils, perform a transport function of delivering foreign particles to the target site for the action of killer neutrophils.

Like wise Natural killer (NK) cells are effector lymphocytes of the innate immune system that control several types of tumors and microbial infections by limiting their spread and subsequent tissue damage.