Ellie Wonders Whether She Has Fully Understood What You Have

Multiple Choice

Ellie wonders whether she has fully understood what you have told her, so she tells you what she knows but she makes one mistake. Which statement made by your friend is INCORRECT?

A) When a person is exposed to an antigen, B cells get activated by TH cells, proliferating and differentiating to form populations of plasma cells and memory cells.
B) Plasma cells produce antibodies which are specific proteins that bind to the antigens, tagging them for elimination by other immune cells such as macrophages and neutrophils.
C) On first exposure to an antigen, a person makes IgM followed by IgG. On second exposure to that same antigen, memory cells produce large amounts of IgG.
D) If a woman experiences a primary exposure to a particular while pregnant, she makes IgM in response. This antibody crosses the placenta and protects her fetus from that pathogen.
E) If a woman experiences a secondary exposure to a particular pathogen while pregnant, she makes IgG that crosses the placenta and protects the fetus from that antigen.