Current Issues in Biology, Volume 6 Scientific American Your Cells Are My Cells Current Issues in Biology, Volume 6 Scientific American

Your Cells Are My Cells Concept Review Many people contain some cells from their mother Woman who have been pregnant often contain cells from children they have carried This condition of carrying some cells from others is microchimerism Microchimerism is likely to contribute to health and disease

Your Cells Are My Cells Concept Review The transfer of cells between mother and fetus during pregnancy was no surprise Given the limited lifetime of most cells, the surprise was that transferred cells could persist throughout a person’s life Stem cells are unusual because they can divide and survive indefinitely to produce specialized cell types Therefore, long term microchimerism suggests that at least some transferred cells are stem cells that take root in the body

Your Cells Are My Cells Concept Review The presence of maternal cells (cells from the mother) is maternal microchimerism Maternal microchimerism can cause autoimmune diseases Autoimmunity occurs when a person’s own cells are recognized as foreign by the immune system

Your Cells Are My Cells Concept Review With maternal microchimerism, some diseases thought to be autoimmune disorders may actually occur when the immune system recognizes and attacks maternal cells For example, in some cases of neonatal lupus, maternal cells integrated into the child’s heart are attacked by the fetal immune system, leading to heart failure

Your Cells Are My Cells Concept Review Maternal microchimerism may also be beneficial when maternal cells help repair damaged organs One example is when maternal cells in the pancreas of diabetics help to maintain insulin production

Your Cells Are My Cells Concept Review Fetal microchimerism occurs when fetal cells are transferred and take root in a mother Fetal microchimerism may be the cause of many diseases in woman traditionally thought to be autoimmune disorders Suggestive evidence is the higher rate of autoimmune diseases in woman than men Another line of evidence is that autoimmune diseases typically strike woman after child-bearing years

Your Cells Are My Cells Concept Review Scleroderma is an autoimmune disease characterized by hardening of the skin Some cases of scleroderma may not be caused by true autoimmunity Instead, scleroderma may occur when the maternal immune system attacks fetal cells residing in the mother Consistent with this idea, female scleroderma patients generally have high levels of fetal microchimerism

Your Cells Are My Cells Concept Review Fetal cells may benefit some mothers who suffer from rheumatoid arthritis, an autoimmune disease marked by chronic, painful joint inflammation In woman suffering from rheumatoid arthritis, the symptoms often improve during pregnancy This improvement is most pronounced in woman with high levels of fetal microchimerism

Your Cells Are My Cells Concept Review Woman who have been pregnant often harbor cells from three generations: from their mothers, their children, and themselves An intriguing question is whether these woman face unique consequences of their extreme microchimerism With microchimerism, our definition of self must be expanded

Your Cells Are My Cells Which of the following is unlikely? Testing Your Comprehension Which of the following is unlikely? a) maternal microchimerism in a man b) maternal microchimerism in a woman c) fetal microchimerism in a man d) fetal microchimerism in a woman

Your Cells Are My Cells Which of the following is unlikely? Testing Your Comprehension Which of the following is unlikely? c) fetal microchimerism in a man

Your Cells Are My Cells Testing Your Comprehension What was surprising about the discovery that maternal cells are transferred to fetuses? a) that it occurs at all b) that nearly half of a person’s cells come from their mother c) that some maternal cells are persistent d) that some maternal cells die

Your Cells Are My Cells Testing Your Comprehension What was surprising about the discovery that maternal cells are transferred to fetuses? c) that some maternal cells are persistent

Your Cells Are My Cells Testing Your Comprehension The persistence of some foreign cells suggests that: a) foreign stem cells were transferred and took root b) long-lived specialized cells were transferred and took root c) transferred cells escape limits to longevity when they grow in a new environment d) transferred cells rapidly become cancerous

Your Cells Are My Cells Testing Your Comprehension The persistence of some foreign cells suggests that: a) foreign stem cells were transferred and took root

Your Cells Are My Cells Autoimmunity occurs when: Testing Your Comprehension Autoimmunity occurs when: a) transferred cells are recognized as foreign b) transferred cells are not recognized as foreign c) a person’s own cells are recognized as foreign d) the immune system fails to recognize pathogens as foreign invaders

Your Cells Are My Cells Autoimmunity occurs when: Testing Your Comprehension Autoimmunity occurs when: c) a person’s own cells are recognized as foreign

Your Cells Are My Cells Testing Your Comprehension Some diseases thought to be autoimmune conditions may actually occur when the immune system: a) recognizes foreign maternal or fetal cells b) recognizes foreign pathogens c) fails to recognize foreign pathogens d) is suppressed by a person’s own cells

Your Cells Are My Cells Testing Your Comprehension Some diseases thought to be autoimmune conditions may actually occur when the immune system: a) recognizes foreign maternal or fetal cells

Your Cells Are My Cells Microchimerism is known to be helpful when: Testing Your Comprehension Microchimerism is known to be helpful when: a) maternal cells in the pancreas of diabetics make insulin b) maternal cells populate the heart of a developing fetus c) fetal cells populate the skin of the mother d) the symptoms of rheumatoid arthritis are relieved after pregnancy

Your Cells Are My Cells Microchimerism is known to be helpful when: Testing Your Comprehension Microchimerism is known to be helpful when: a) maternal cells in the pancreas of diabetics make insulin

Your Cells Are My Cells Testing Your Comprehension Woman who have been pregnant often harbor cells from ______ generation or generations a) one b) two c) three d) four

Your Cells Are My Cells Testing Your Comprehension Woman who have been pregnant often harbor cells from ______ generation or generations c) three

Your Cells Are My Cells Thinking About Science Which of the following cases of microchimerism would be easiest to detect experimentally? a) a female fetal cell in a mother b) a male fetal cell in a mother c) a maternal cell in a daughter d) a maternal cell in a son

Your Cells Are My Cells Thinking About Science Which of the following cases of microchimerism would be easiest to detect experimentally? b) a male fetal cell in a mother

Your Cells Are My Cells Biology and Society Since nothing can be done to control the degree of microchimerism and the extent of microchimerism in disease is not clear, government funds should not go to microchimerism research when there are known killers such as breast cancer and diabetes waiting for cures Strongly Agree Disagree A. E. C. B. D.

Your Cells Are My Cells Interpreting Charts and Graphs What conclusion can be drawn from this figure that shows the number of foreign cells in type I diabetes patients, their unaffected siblings, and unrelated non-diabetic individuals? a) all diabetics have foreign cells b) foreign cells cause diabetes c) there is a correlation between increased numbers of foreign cells and diabetes d) people without diabetes are not microchimeric From: Nelson et al. (2007) PNAS, USA 104:1637-1642

Your Cells Are My Cells Interpreting Charts and Graphs What conclusion can be drawn from this figure that shows the number of foreign cells in type I diabetes patients, their unaffected siblings, and unrelated non-diabetic individuals? c) there is a correlation between increased numbers of foreign cells and diabetes From: Nelson et al. (2007) PNAS, USA 104:1637-1642