Type I hypersensitivity is due to release of inflammatory mediators from_____, and type IV hypersensitivity is due to the actions of_____.

a. TH cells; macrophages

b. neutrophils; TH cells

c. B cells; TC cells

d. mast cells; TH cells

Video transcript

Hi, everyone. Let's take a look at this practice problem together. A tuberculin skin test could produce a type four hypersensitivity reaction, which of the following cells is responsible for the reaction. The answer options are a mast cells, bt cells, C basophils and DB cells. So, a tuberculin skin test is a tool that is used to test whether a person has tuberculosis and a type four hypersensitivity reaction is a delayed allergic reaction. So there's an excessive immune response and it can take a day or more to develop a type four hypersensitive sensitivity reaction is self mediated, meaning that the antibodies are not necessary. So, taking a look at the answer options. Option. A mast cells, mast cells are important for the inflammatory response. So they enhance inflammation by releasing histamine and heparin. However, they're not responsible for producing a hypersensitivity reaction. So option A is incorrect option. C basophils, basophils are similar in both size and function to mast cells. So they also enhance inflammation by again releasing heparin and histamine. So option C is incorrect. Option DB cells, the role that B cells have in an allergy response is to produce the IgE antibodies. They are not responsible for producing the whole hypersensitivity reaction. So option D is also incorrect. The correct answer is option BT cells. So in type four hypersensitivity reactions, the T cells produce the whole inflammatory response. So the correct answer is option BT cells. All right, everyone. I hope you found this helpful and I'll see you soon for the next practice problem.