Innate Immunology: Immune System Overview and Functions

What are the two main branches of the immune system?

Innate immune system and adaptive immune system.

What is the primary role of the innate immune system?

Acts as the first line of defense, responding quickly and non-specifically to pathogens.

How does the adaptive immune system differ from the innate immune system?

It has a slower response and is highly specific, recognizing distinct parts of pathogens.

What is a key function of inflammation generated by the innate immune system?

To recruit immune cells to sites of infection and facilitate communication.

Why is the innate immune system vital for survival?

Without it, effective host defense against pathogens is not possible.

What phrase summarizes the rapid response mechanism of the innate immune system?

Shoot first, ask questions later.

What is essential for effective immune responses among immune cells?

Communication between immune cells.

What are the types of communication in the immune system?

Direct communication via ligand-receptor interactions and indirect communication through soluble factors like cytokines.

What are cytokines?

Small, soluble proteins secreted by immune cells that play a key role in signaling.

Can you name an example of a cytokine important for immune responses?

Interleukins (e.g., IL-10) and interferons (e.g., IFN-ɣ).

What functions do cytokines serve in the immune response?

They induce pro-inflammatory responses, anti-inflammatory effects, and differentiation of cell populations.

What distinguishes chemokines from cytokines?

Chemokines primarily direct cell movement, while cytokines are involved in signaling and differentiation.

What are the major types of innate immune cells?

Granulocytes (neutrophils, eosinophils, basophils, mast cells) and monocytes/macrophages.

What is the role of neutrophils in the innate immune system?

They are the most abundant leukocytes and act as first responders to infection.

How do eosinophils contribute to immune defense?

They are important for defense against helminths and bacteria.

What role do mast cells play in the immune response?

They are involved in defense against parasites and allergic reactions.

What is the function of dendritic cells in immunity?

They serve as a bridge between the innate and adaptive immune systems, presenting antigens to T cells.

How do dendritic cells mature and what is their importance?

They mature upon encountering pathogens and secrete inflammatory cytokines, crucial for initiating adaptive responses.

What mechanisms allow innate immune cells to access infection sites?

Chemokine signaling and adhesion molecules.

What is the difference between homeostatic and inflammatory chemokines?

Homeostatic chemokines are constitutively expressed, while inflammatory chemokines are induced upon activation.

What is the main function of CXCL8 chemokine?

It primarily chemoattracts neutrophils to sites of infection.

What distinguishes leukocyte adhesion deficiency (LAD)?

Defects in the beta-2 subunit of integrins lead to impaired leukocyte migration.

What are adhesion molecules and their role in the immune response?

They are crucial for the migration of innate immune cells into tissues.

What is the first step in the leukocyte recruitment process?

Activation of the endothelium by inflammatory cytokines.

What happens during the rolling stage of leukocyte recruitment?

Selectins on the activated endothelium mediate initial rolling of leukocytes.

What is flow cytometry used for in immunology?

Analyzing physical and chemical characteristics of cells and can identify rare cell populations.

How does flow cytometry visualize cells?

Cells are labeled with fluorescent antibodies specific to surface proteins.

What is the purpose of gating in flow cytometry?

To separate populations based on specific surface markers stained with different fluorophores.

What are histograms used for in flow cytometry?

They provide a simple representation showing the distribution of cell populations.

What are dot plots used for in flow cytometry?

They allow for multiparametric analysis and display relationships between multiple markers.

What is fluorescence-activated cell sorting (FACS)?

A flow cytometry technique used for isolating specific cell populations.

What clinical relevance do cytokines have in immune responses?

They are important therapeutic targets for various diseases.

What is the primary function of chemokines in the immune response?

Act as traffic directors, guiding immune cells to sites of infection.

Why is chemokine signaling important during inflammation?

It creates concentration gradients that guide immune cell migration.

What is the role of integrins in leukocyte migration?

Integrins interact with ICAMs on endothelial cells, facilitating tissue infiltration.

How do inflammatory cytokines affect myeloid cell recruitment?

They mediate the immune response, primarily during inflammation.

What do CCL3 chemokines attract to the site of infection?

They attract macrophages, playing a role in the inflammatory response.

What is a characteristic of mature dendritic cells?

They present antigens to T cells and migrate to lymph nodes.

What results from ineffective immune response due to LAD?

Recurrent bacterial infections and poor wound healing.

What happens during extravasation in leukocyte recruitment?

Leukocytes move from the bloodstream into the tissue.

What is an essential characteristic of chemokines during inflammation?

They exhibit selective tissue expression.

What is the significance of multi-antigen specificity in the innate immune system?

It allows the innate immune system to respond to a wide range of pathogens.

How do inflammatory chemokines differ from homeostatic chemokines?

Inflammatory chemokines are induced upon activation, while homeostatic ones are always present.

What key chemokines are involved in attracting eosinophils and basophils?

CCL11 interacts with receptor CCR3.

What does the term 'extravasation' refer to?

The process by which leukocytes exit the bloodstream to enter tissues.

What is the importance of the communication between immune cells?

To coordinate their actions during immune responses effectively.

Why are chemokines important for homeostatic functions in immunity?

They play roles in the development and maintenance of immune cells.

What role does the expression of selectins on endothelium play?

It allows leukocytes to roll along the blood vessel wall.

How do immune cells respond to injury according to cytokine signaling?

Cytokines mediate actions to recruit and activate immune cells to the injury site.

What is the role of plasmacytoid dendritic cells (pDCs)?

They specialize in viral detection.

What do you understand by 'immunological memory' in the adaptive system?

It is the ability of the immune system to remember past infections for quicker response.

What is the role of the most abundant leukocytes during infection?

Neutrophils respond first to infections and are critical for initiating the immune response.

How do adhesion molecules contribute to inflammation?

They facilitate the migration of immune cells from the bloodstream to affected tissues.

What is the significance of cytokines in therapeutic interventions?

They are critical targets for developing treatments for various diseases.

What are interleukins?

A type of cytokine that plays an important role in immune responses.

What happens during the maturation of dendritic cells in response to pathogens?

They activate and start presenting antigens to T cells.

What characterizes the trafficking of immune cells guided by chemokines?

Chemokines create a gradient that directs immune cells towards infection sites.

What is the relationship between inflammation and immune cell recruitment?

Inflammation triggers the production of chemokines that recruit immune cells.