Immunology Overview

What type of hypersensitivity is characterized as delayed?

What triggers delayed hypersensitivity in some individuals?

Which of the following is an example of a substance that may cause a delayed hypersensitivity reaction?

What is a possible immune response to insect bites?

Which characteristic best describes delayed hypersensitivity?

What do antibodies in the recipient's plasma target during blood group incompatibility?

What is the relationship between Streptococcal bacterial cell wall antigens and blood group incompatibility?

What can occur if there is blood group incompatibility?

What is a potential consequence of the recipient's antibodies attacking the donor's RBCs?

How does blood group incompatibility relate to the concept of self-antigens?

Immune Response and Antibody Reaction

Streptococcal bacterial cell wall antigen can cross-react with self-antigens, leading to blood group incompatibility.
Recipient's plasma antibodies may attack donor red blood cells (RBCs), resulting in hemolytic reactions.
Type IV hypersensitivity is characterized by delayed immune responses, often involving T-cells rather than antibodies.

Autoimmunity and Hypersensitivity Mechanisms

Immune system may mistakenly identify substances (e.g., drugs, foods) as threats, triggering autoimmunity.
Antibodies (IgG or IgM) bind to target cell membranes via their Fab region, initiating an immune attack.
Complement activation leads to the formation of a membrane attack complex, damaging target cell membranes.
Opsonization occurs when complement proteins attract phagocytes to facilitate the destruction of target cells.

Therapeutics and Treatment Options

Cromolyn sodium is used to mitigate allergic reactions and asthma.
Bronchodilators are medications that relax and open airways.
Monoclonal anti-IgE antibody, such as omalizumab, helps reduce allergic responses by targeting IgE.

Clinical Examples of Hypersensitivity

Rheumatic fever exemplifies type II hypersensitivity, where antibodies form against Streptococcus pyogenes following untreated infections.
Autoimmune conditions arise from the immune system's faulty recognition of self versus non-self, leading to tissue damage and disease.

Role of Dentists in Autoimmunity

Dentists are crucial in identifying emerging autoimmune pathologies, often through oral examinations and patient history.

This quiz covers key concepts related to immune responses, including antibody reactions and mechanisms of autoimmunity and hypersensitivity. It discusses specific cases like blood group incompatibility and therapeutic options for treating allergic reactions. Test your knowledge on how the immune system interacts with self-antigens and the implications for health.