Innate vs Adaptive Immunity - Anatomy and Physiology
- Which form of adaptive immunity is mediated by antibodies in body fluids?
- Humoral immunity. Antibodies are secreted by plasma cells, which develop from activated B cells.
- How do adaptive lymphocytes come to have millions of different antigen receptors?
- Random rearrangement of receptor gene segments during lymphocyte development gives each new clone a unique receptor.
- How does the specificity of adaptive immunity differ from that of innate immunity?
- Innate receptors recognize patterns shared by many microbes; each adaptive lymphocyte clone has a unique receptor for one specific antigen.
- Which form of adaptive immunity directly kills infected body cells?
- Cell-mediated immunity, carried out mainly by cytotoxic T cells.
- On a second exposure to a toxin, antibodies appear faster but neutrophil recruitment is unchanged. Which branch explains the unchanged part?
- Innate immunity. Because it lacks memory, neutrophil recruitment repeats with the same timing and intensity on each exposure.
- Why does a first (primary) adaptive immune response take several days to become effective?
- Rare lymphocytes specific for the antigen must first be activated and then multiply by clonal expansion before enough are available.
- Which branch of immunity responds within minutes to hours and reacts the same way on every exposure?
- Innate immunity. It has no memory, so its speed and strength do not improve with repeat exposure.
- What receptors do innate immune cells use to recognize broad classes of microbes?
- Pattern recognition receptors, such as Toll-like receptors, which bind conserved microbial molecules (PAMPs) like lipopolysaccharide.
- Which two types of lymphocytes carry out adaptive immunity?
- B lymphocytes and T lymphocytes. NK cells are lymphocytes too, but they belong to innate immunity.
- What feature of adaptive immunity produces a faster, stronger response to a second exposure?
- Immunological memory. Memory B and T cells left from the first response react quickly to the same antigen.
- Which cell is the main link between innate and adaptive immunity, presenting antigen to naive T cells?
- The dendritic cell. It captures antigen in tissues and carries it to lymph nodes to activate T cells.
- Classify the complement proteins as part of innate or adaptive immunity.
- Innate. Complement is always present in plasma and can act without prior exposure, although antibodies can trigger its classical pathway.