COPY: Types of Immune Response: Hyperreactivity Types III & IV

It is mediated by IgG and IgM antibodies against soluble antigens, leading to the formation of immune complexes.

Type III reactions occur 3-8 hours after exposure, whereas Type IV reactions begin 24-72 hours later.

Serum sickness is a systemic disease caused by Type III hypersensitivity.

<p>The Arthus reaction is characterized by a localized immune response causing tissue necrosis at the injection site.</p> Signup and view all the answers

<p>T lymphocytes mediate the destruction of cells in Type IV hypersensitivity, often along with macrophages and cytokines.</p> Signup and view all the answers

<p>necrotizing vasculitis and fibrinoid necrosis are key features of tissue injury in Type III hypersensitivity.</p> Signup and view all the answers

<p>Renal glomeruli are a favored site for immune complex deposition in autoimmune diseases.</p> Signup and view all the answers

<p>Type IV hypersensitivity reactions typically have a latency period of 24 to 72 hours after antigen exposure.</p> Signup and view all the answers

<p>Inflammatory infiltrate typically includes neutrophils in tissues affected by Type III hypersensitivity.</p> Signup and view all the answers

<p>One distinguishing feature is that Type III reactions involve soluble antigens and immune complexes, while Type IV reactions are mediated by T cells.</p> Signup and view all the answers

<p>Type IV hypersensitivity is cell-mediated and involves a delayed reaction, unlike the antibody-mediated responses of the first three types.</p> Signup and view all the answers

<p>CD4+ T-helper cells activate macrophages and release inflammatory mediators, leading to delayed hypersensitivity reactions.</p> Signup and view all the answers

<p>The Mantoux test involves injecting a mycobacterial antigen into the skin, resulting in a detectable reaction within 24 to 48 hours, indicating prior exposure to tuberculosis.</p> Signup and view all the answers

<p>Granuloma formation is the aggregation of epithelioid cells due to persistent intracellular antigens that stimulate T cells unable to eliminate the pathogen.</p> Signup and view all the answers

<p>Epithelioid cells are transformed macrophages with abundant, large, and pink cytoplasm, resembling epithelial cells.</p> Signup and view all the answers

<p>CD8+ T cells mediate cytotoxicity by inducing apoptosis in antigen-bearing cells.</p> Signup and view all the answers

<p>Examples include cytotoxic reactions against virus-infected cells, transplant rejections, and Type 1 diabetes.</p> Signup and view all the answers

<p>Chronic graft-versus-host disease arises from the activation of T cells against host tissues post-transplant, leading to prolonged immune responses.</p> Signup and view all the answers

<p>Allergic contact dermatitis represents a specific type IV hypersensitivity reaction triggered by environmental chemicals causing skin inflammation.</p> Signup and view all the answers

<p>The skin shows epidermal necrosis, inflammation, rashes, and blisters during allergic contact dermatitis.</p> Signup and view all the answers