Question

other cells called _____ cells, patrol your blood and lymph looking for pathogens and are unique because they can kill ______ cells if they are infected. Normal healthy cell has protein on surface called MHC1, infected ones do not have them, so the cells detect it, poke it with an enzyme and trigger _____ (programmed cell death)

Answer 1

Natural killer (NK) cells target and kill virus-infected cells that lack MHC class I molecules on their surface by inducing apoptosis, a type of programmed cell death.

Step-by-step explanation:

The cells that patrol your blood and lymph looking for pathogens are natural killer (NK) cells. These cells are unique because they can kill virus-infected cells that have altered or absent major histocompatibility complex (MHC) class I molecules on their surface. Normal, healthy cells have MHC class I proteins that present fragments of proteins from within the cell to T cells. When cells are infected with viruses, they often display an altered MHC class I complement or may not have these molecules at all, which is a signal to NK cells to take action. NK cells detect infected cells and deliver enzymes that induce apoptosis, which is a form of programmed cell death, effectively destroying the pathogen-infected cells.

Natural Killer (NK) cells are a type of lymphocyte that patrols the blood and lymph to identify and kill cells that are infected with pathogens. They are unique because they can recognize cells that do not have major histocompatibility class (MHC) I proteins on their surface, which are usually present on healthy cells. When NK cells detect an infected cell, they use an enzyme to poke and trigger programmed cell death, a process known as apoptosis.