22 Questions
What is the initial response to microbes to prevent, control, or eliminate infection?
Innate immunity
Which of the following substances stimulate innate immune responses and are recognized by pattern recognition receptors (PRRs)?
Pathogen-associated molecular patterns (PAMPs)
What type of receptors on immune cells bind to PAMPs?
Pattern recognition receptors (PRRs)
Which of the following is NOT a function of cytokines?
Binding to PAMPs
Which type of pattern recognition receptor is involved in the response to bacterial DNA?
TLR9
Which of the following is a principal effector cell of innate immunity?
Natural killer (NK) cells
What is the role of neutrophils in the innate immune response?
Phagocytosing and destroying microbes
Which of the following best describes the function of macrophages in innate immunity?
Long-lived cells that can differentiate and undergo cell division
Which of the following is NOT a step in the process of phagocytosis?
Antibody production
Which type of cell is specialized in responding to viral infections by secreting type-I interferons?
Dendritic cells
What process is involved in the recruitment of leukocytes to sites of infection?
All of the above
Which of the following bacteria can live within the phagolysosome?
Rickettsia species
Innate immunity is always sufficient to eradicate the microbe completely.
False
Pattern recognition receptors (PRRs) of the innate immune system are encoded in germline DNA.
True
Toll-like receptors (TLRs) are an evolutionary conserved family of PRRs expressed on many cell types.
True
Neutrophils are long-lived cells that can differentiate and undergo cell division.
False
Defensins are cysteine-rich peptides with antimicrobial properties.
True
Natural killer (NK) cells can kill microbe-infected cells without the need for antibodies.
True
Complement proteins are involved in promoting inflammation and lysing microbes.
True
Chronic granulomatous disease is characterized by the inability to generate reactive oxygen intermediates.
True
Chemokines are small peptides that stimulate leukocyte movement and regulate migration from the blood to tissues.
True
Inflammation is beneficial unless unregulated.
True
Study Notes
Innate Immunity
- The initial response to microbes to prevent, control, or eliminate infection is Innate Immunity.
- Pattern recognition receptors (PRRs) recognize Pathogen-associated molecular patterns (PAMPs), stimulating innate immune responses.
- PRRs on immune cells bind to PAMPs, including Toll-like receptors (TLRs), an evolutionary conserved family of PRRs expressed on many cell types.
- Cytokines activate other cells, amplify innate and adaptive responses, and trigger inflammatory responses, but do not bind to PAMPs.
Cells Involved in Innate Immunity
- Neutrophils phagocytose and destroy microbes.
- Macrophages are long-lived cells that can differentiate and undergo cell division, and are involved in phagocytosis and the response to bacterial DNA.
- Natural killer (NK) cells are principal effector cells of innate immunity and can kill microbe-infected cells without the need for antibodies.
Phagocytosis
- The process of phagocytosis involves adhesion/recognition, internalization, and fusion with lysosomes, but not antibody production.
- Defensins are cysteine-rich peptides with antimicrobial properties.
Leukocyte Recruitment and Inflammation
- Chemokines stimulate leukocyte movement and regulate migration from the blood to tissues, promoting inflammation.
- Inflammation is beneficial unless unregulated, and involves the recruitment of leukocytes to sites of infection through rolling adhesion, chemokine-mediated increase in integrin affinity, and stable integrin-mediated adhesion.
Specialized Cells and Pathogens
- Dendritic cells are specialized in responding to viral infections by secreting type-I interferons.
- Some bacteria, such as Mycobacteria species and Rickettsia species, can live within the phagolysosome.
- Chronic granulomatous disease is characterized by the inability to generate reactive oxygen intermediates.
Test your knowledge on immunology and immune responses with these multiple-choice questions. Learn about the different types of immunity, receptors, and responses to microbes.
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