ALFS, L7: Innate Immunity

Given definition, answer w/ term

Innate immunity

1 of the 2 Main Arms of Immune Response:

• Defining Characteristics:

  • Non-specific

  • Very rapid

  • Broad recognition

  • In all animals

  • No memory

• Components:

  • Physical barriers – skin, ciliated mucous membranes, saliva, flushing action of urine and tears, and stomach acid

  • Humoral mechanisms: secretions, for example…

    • Enzymes

    • Irone chelaters

    • Anti-microbial peptides

    • Complement cascade

  • Factors which regulate species specificity – receptors for pathogens, nutritional requirements, temperature, and pH

  • Cellular mechanisms – phagocytosis and granules

Enzymes

1 of the 4 Humoral Mechanisms of Innate Immunity:

Examples include :

• Lysosome – present in tears, saliva, milk, and mucus break down bacterial walls

• Proteases

Iron chelaters

1 of the 4 Humoral Mechanisms of Innate Immunity:

Examples include :

• Lactoferrin – present in milk, sequesters iron from bacteria

• Lactoperoxidase

Anti-microbial peptides

1 of the 4 Humoral Mechanisms of Innate Immunity:

Examples include :

• β-defensins – found in gut mucosa that insert themselves in microbial membranes and punch holes in it; very species specific

• Bctenicin

Complement cascade

1 of the 4 Humoral Mechanisms of Innate Immunity:

• Proteins that link together to remove pathogens, particularly bacteria

Haematopoiesis; myeloid or lymphoid cells

Immune cells arise through _______ in the bone marrow, and based on growth factors such as colony stimulating factors and interleukins (cytokines), will become either _______ or _______ cells

Neutrophils

1 of the 6 Cells of the Innate Immune System:

• Function: :

  • Killing intracellular pathogens via phagocytosis (uptake)

  • Killing extracellular pathogens by releasing extracellular traps (NETs)

• Clinical Significance:

  • Easily seen in blood smears, identifiable segmented nuclei

  • Numbers increase massively during disease/inflammation processes

Eosinophils

1 of the 6 Cells of the Innate Immune System:

• Function:

  • Key in immune response to parasites, especially nematode worms

  • Central to the damaging inflammatory processes that occur during allergic reactions

  • Release cytotoxic molecules for direct killing

• Clinical Significance:

  • Easily seen in blood smears (stain pink with eosin), identifiable segmented nuclei

  • Numbers increase massively during allergic reactions or worm infestation

Basophils

1 of the 6 Cells of the Innate Immune System:

• Function:

  • Histamine release lead to:

    • Increase in vascular permeability

    • Smooth muscle contraction

  • IL-4 and IL-13 release lead to:

    • Th2 lymphocyte differentiation

    • IgE production

• Clinical Significance:

  • Dark cytoplasm filled with granulesNumbers increase during allergic reactions

Mast cells

1 of the 6 Cells of the Innate Immune System:

• Function:

  • Active during parasitic infections and allergic reactions

  • Release wide variety of inflammatory mediators by allergens, pathogens, and physiological mediators

• Clinical Significance:

  • Don’t circulate in blood, stay within a tissue

Monocytes

1 of the 6 Cells of the Innate Immune System:

• Function: “sentinel cells”

  • Circulate through tissues where they may be retained and further differentiate into macrophages or dendritic cells during infection/inflammation

  • Link the adaptive and innate immune response

• Clinical Significance:

  • Characteristic kidney shaped nucle

Natural killer cells

1 of the 6 Cells of the Innate Immune System:

• Function:

  • Release cytotoxic granules that kill infected cells and can affect extracellular parasites

  • Release cytokines to influence adaptive immune response

  • Able to recognize self from non-self via complex set of receptors

  • Link the adaptive and innate immune response

Pattern recognition receptors (PRRs)

Pathogen associated molecular patterns (PAMPS) are recognized by _______. Recognition triggers intracellular signaling cascades, which leads to altered gene expression and downstream functions of the specific cell that has recognized the PAMP