Which type of hypersensitivity is not antibody mediated?
a. Type I hypersensitivities
b. Type II hypersensitivities
c. Type III hypersensitivities
d. Type IV hypersensitivities
e. Antibodies mediate all of these.

Verified step by step guidance

Step 1: Understand the classification of hypersensitivity reactions. There are four main types: Type I, II, III, and IV, each with distinct immune mechanisms.

Step 2: Recall that Type I, II, and III hypersensitivities are antibody-mediated. Specifically, Type I involves IgE antibodies, Type II involves IgG or IgM antibodies targeting cells, and Type III involves immune complexes formed by antibodies.

Step 3: Recognize that Type IV hypersensitivity is different because it is cell-mediated, primarily involving T cells rather than antibodies.

Step 4: Review the role of T cells in Type IV hypersensitivity, which leads to tissue damage through the activation of macrophages and cytotoxic T cells without the involvement of antibodies.

Step 5: Conclude that the hypersensitivity type not mediated by antibodies is Type IV hypersensitivity.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Types of Hypersensitivity Reactions

Hypersensitivity reactions are immune responses that cause tissue damage. They are classified into four types (I-IV) based on the immune mechanism involved, ranging from immediate allergic reactions to delayed cellular responses.

Antibody-Mediated Hypersensitivity (Types I, II, III)

Types I, II, and III hypersensitivities involve antibodies. Type I is IgE-mediated allergic reactions, Type II involves IgG or IgM antibodies targeting cells, and Type III results from immune complex deposition causing inflammation.

Cell-Mediated Hypersensitivity (Type IV)

Type IV hypersensitivity is a delayed-type reaction mediated by T cells, not antibodies. It involves sensitized T lymphocytes that release cytokines, leading to macrophage activation and tissue damage, typically occurring 48-72 hours after exposure.

Recommended video:

Guided course