Adaptive Immunity and Immunization

These flashcards cover key concepts and definitions related to adaptive immunity, immunization, and the mechanisms involved in immune responses.

What are the two branches of adaptive immunity?

B cells and T cells.

What are the characteristics of adaptive immunity?

Discrimination, Diversity, Specificity, and Memory.

What is acquired, specific immunity also known as?

Adaptive immunity.

What is the role of antigen-presenting cells (APCs)?

They alert T-cells and/or B-cells by processing and displaying antigens.

What are the two forms of natural immunity?

Active immunity and passive immunity.

How do T-cell-dependent B-cell activation and T-cell-independent B-cell activation differ?

T-cell-dependent requires help from T-helper cells, while T-cell-independent does not.

What are the five classes of antibodies?

IgG, IgA, IgM, IgD, IgE.

What is herd immunity?

Protection from disease that occurs when a significant portion of a population becomes immune.

What is the primary response to an antigen?

The immune system produces IgM initially, followed by IgG.

What are the stages of adaptive immune function?

Lymphocyte development and clonal deletion, antigen presentation, challenge by antigens, and lymphocyte response.

What are the requirements for an effective vaccine?

Low side effects, protection against wild pathogens, stimulate both B and T-cell responses, long-lasting effects, not requiring numerous doses, inexpensive, and easy to administer.

What are the three phases of vaccine trials according to the FDA?

Phase I: safety testing with healthy volunteers; Phase II: effectiveness testing with a larger group; Phase III: comprehensive testing with thousands of volunteers.

What are the main types of T cells and their functions?

1. Helper T cells ($T_H$ cells): Coordinate immune responses by activating other immune cells.
2. Cytotoxic T cells ($T_C$ cells): Directly kill infected or cancerous cells.
3. Regulatory T cells ($T_{reg}$ cells): Suppress excessive immune responses to prevent autoimmunity.

How do antibodies protect the body?

Antibodies protect by:

• Neutralization: Blocking the binding of pathogens or toxins to host cells.
• Opsonization: Marking pathogens for phagocytosis.
• Agglutination: Clumping pathogens together, making them easier to clear.
• Complement Fixation: Activating the complement system to lyse cells or enhance inflammation.
• Antibody-dependent cell-mediated cytotoxicity (ADCC): Recruiting natural killer (NK) cells to destroy target cells.

What is natural active immunity?

Immunity developed after natural exposure to a pathogen, leading to the production of antibodies and memory cells by the individual's own immune system.

What is natural passive immunity?

Temporary immunity acquired by receiving antibodies from another person or animal, such as maternal antibodies transferred to a fetus or infant via the placenta or breast milk.

What is the secondary response to an antigen?

A faster, stronger, and more prolonged immune response upon re-exposure to the same antigen, characterized by a rapid production of mainly IgG antibodies due to the presence of memory cells.