Introduction to the Immune System

This set of flashcards covers key concepts from an introduction to the immune system, including various immune responses, types of immunity, roles of different cell types, and important clinical correlations.

What is immunity?

Defense mechanisms that protect the host against infectious pathogens.

What can immune responses target besides pathogens?

Harmless environmental antigens and self antigens, leading to allergies and autoimmunity.

What is immunology?

The study of immune system structure and function.

What are therapeutic manipulations enabled by an accurate understanding of the immune system?

Vaccines and monoclonal antibodies.

What is the major function of the immune system?

Preventing and eradicating infections.

What does vaccination stimulate?

Protective immunity.

What is herd immunity?

Immunity that requires vaccination or natural infection within a population.

What is autoimmunity?

When the immune response mistakenly targets self antigens.

What is tumor immunity?

The immune response against tumors.

What are the two types of adaptive immunity?

Humoral immunity and cell-mediated immunity.

What is the role of phagocytes?

To engulf and destroy pathogens.

What mediates humoral immunity?

Antibodies produced by B lymphocytes.

What do CD4⁺ Helper T lymphocytes do?

Activate phagocytes via cytokines.

What do CD8⁺ Cytotoxic T lymphocytes do?

Kill infected host cells directly.

What is active immunity?

Induced by exposure to an antigen, generating an immune response and memory.

What is passive immunity?

Transfer of antibodies from an immune individual to a naive individual.

What is the function of memory lymphocytes?

To provide rapid responses to previously encountered antigens.

What is the purpose of clonal expansion?

To rapidly proliferate antigen-specific lymphocytes after recognition.

What characterizes innate immunity?

Immediate response and present in all individuals at all times.

What is the first line of defense in innate immunity?

Epithelial barriers and antimicrobial peptides.

What do antigen-presenting cells do?

Capture antigens and present them to lymphocytes in secondary lymphoid organs.

What is self-tolerance?

Prevention of immune responses against self antigens.

What is the clinical importance of understanding immune dysregulation?

It is key for developing novel treatments for autoimmune diseases.

What triggers the activation of B lymphocytes in the adaptive immune response?

Antigen recognition.

What is the role of effector cells in the immune response?

To eliminate pathogens and aid in recovery.

What happens to effector lymphocytes after the antigen is cleared?

They undergo apoptosis to prevent excess inflammation.

Which cells are primarily responsible for cell-mediated immunity?

T lymphocytes.

What happens to lymphocytes in secondary lymphoid organs?

They encounter antigens and may become activated.

What do maternal antibodies provide to a fetus?

Protection against infections.

How does the immune system return to its resting state after a response?

Through contraction and self-limitation.

What is a clinical correlation of failure in immune system contraction?

It contributes to chronic inflammatory diseases.

What is a crucial element of vaccination strategies?

Immunologic memory.

What marks the difference between naive and memory T cells?

Memory T cells respond rapidly upon re-exposure to antigens.