List the applicable hypersensitivities (type I, II, III, IV) as they relate to the description. Note, more than one type of hypersensitivity may be listed for a given description.


IgG antibodies can mediate type _________________hypersensitivities.
T cells mediate type _________________ hypersensitivities.
Type _________________ hypersensitivities may be generated in response to pharmaceutical drugs.
Type _________________ hypersensitivities may be associated with autoimmunity.
Type _________________ hypersensitivities require a sensitizing exposure.
IgE antibodies can mediate type _________________hypersensitivities.

Verified step by step guidance

1. Identify the role of IgG antibodies in hypersensitivity reactions. IgG antibodies are primarily involved in Type II and Type III hypersensitivities.
2. Determine which hypersensitivity is mediated by T cells. T cells are responsible for Type IV hypersensitivity reactions.
3. Consider the hypersensitivity types that can be triggered by pharmaceutical drugs. Both Type I and Type II hypersensitivities can be drug-induced.
4. Explore the association of hypersensitivity types with autoimmunity. Type II, Type III, and Type IV hypersensitivities can be linked to autoimmune conditions.
5. Understand the requirement of sensitizing exposure in hypersensitivity reactions. Type I hypersensitivity requires an initial sensitizing exposure to the allergen.

Key Concepts

Types of Hypersensitivity

Hypersensitivity reactions are classified into four types (I-IV) based on the immune mechanism involved. Type I hypersensitivity is mediated by IgE antibodies and is associated with allergic reactions. Type II involves IgG or IgM antibodies that target specific cells, leading to cytotoxicity. Type III is characterized by immune complex formation, while Type IV is mediated by T cells and is delayed in nature, often seen in contact dermatitis.

Role of Antibodies

Antibodies, particularly IgG and IgE, play crucial roles in mediating hypersensitivity reactions. IgG antibodies are primarily involved in Type II and Type III hypersensitivities, where they can lead to cell damage or inflammation. In contrast, IgE antibodies are central to Type I hypersensitivity, triggering allergic responses upon binding to allergens and activating mast cells and basophils.

T Cell Mediation

T cells are essential components of the adaptive immune response and are specifically involved in Type IV hypersensitivity reactions. Unlike antibody-mediated hypersensitivities, Type IV reactions are delayed and occur when sensitized T cells respond to previously encountered antigens. This type of hypersensitivity is often associated with autoimmune diseases and can manifest as skin rashes or other inflammatory responses.