Final answer:
The false statement about type 1 reactions is they involve T helper cells. Type 1 hypersensitivity reactions are primarily characterized by the involvement of IgE antibodies, mast cells, and histamine release.
Step-by-step explanation:
The false statement about type 1 reactions is: A) they involve T helper cells. Type 1 hypersensitivity reactions, also known as immediate hypersensitivity reactions, primarily involve IgE antibodies and not T helper cells directly. These reactions are characterized by symptoms that occur rapidly upon secondary exposure to an antigen due to the presence of IgE antibodies bound to mast cells and basophils.
The symptoms are largely due to the release of histamine and other inflammatory molecules from mast cells, which occurs after the IgE antibodies on these cells bind to the antigen. Hence, statements B), C), D), and E) are all true characteristics of type I hypersensitivity reactions. Unlike type I, type II hypersensitivity reactions involve antibodies that can cause cell lysis (cytotoxicity) and are characterized by strong antibody reactions against cell surface or matrix antigens.