17. Development of the immune response. Recognition of antigens. The role of APC and MHC molecules. Dynamics of the immune response – primary and secondary immune response. Genetic control of the immune response. Humoral regulation of the immune response. Allergy – definition and types. Immediate allergic reactions – anaphylaxis, atopy, clinical significance. Cytotoxic allergic reactions. Allergic phenomena due to immune complexes – serum sickness, Arthus phenomenon, clinical significance. Delayed type hypersensitivity – tuberculin skin test (Mantoux), contact dermatitis. Clinical significance of hypersensitivity in Dental medicine.

Immune response - dynamics of the immune response. Humoral immunity.

• The immune response is the collective, coordinated response of immune cells and molecules to defend the host from infectious disease and preserve genetic/antigenic integrity.
• It involves recognizing and tolerating self, while recognizing and rejecting non-self foreign agents.

Dynamics of the Immune Response

• The immune response develops after a latent period of 1-2 weeks following initial exposure to an inducing antigen.
• There are two main phases or types of immune response dynamics:
• Primary Immune Response: Occurs upon the first encounter with an antigen
• Characterized by a latent phase (1-2 weeks) before antibodies are detectable. During this phase, B cells are activated and differentiate
• IgM is typically the first antibody produced and is effective in the early phase of infection
• Antibody levels rise, but often reach a lower peak and decline relatively quickly compared to the secondary
• Secondary Immune Response: Occurs upon subsequent encounters with the same specific antigen.
• Results from the development of immune memory after the primary response
• Characterized by a faster and stronger response.
• The latent phase is shorter
• Antibody levels rise sooner, reach a higher level, and are sustained longer.
• Often involves a switch from IgM production to predominantly IgG production, mediated by memory B cells. IgG is the most abundant antibody in the secondary response.