Question

Mutations of immunoglobulin genes can have major consequences for immune function. One rare mutation causes monomeric antibodies to become polymeric. Which of the following statements will be true for a pregnant woman with this mutation? She will have fewer infections than normal Her basophils and mast cells will release more histamine than usual Fewer antibodies will be found in breast milk Fewer antibodies will be available to protect a developing fetus

Answer 1

Answer: (D) Fewer antibodies will be available to protecct the fetus.

An antibody to cross the placenta, antobody should cross the syncytiotrophoblast cells from the intervillous space and the fetal vessel endothelium. Therefore, only monomeric IgG, the only antibody isotype to cross the placenta because of its specific receptors to facilitate passage through the human placenta, thereby providing protection to the fetus in utero.

Human breast milk express polymeric IgA.

Though release of more histamine by mast cells and basophills hold true, when it comes to pregnant woman, option D is appropriate.