Ch 13 Innate and Adaptive Immunity

small proteins that act as signaling molecules, facilitating communication among immune cells. They play a pivotal role in both the innate and adaptive immune responses

• Cytokines exhibit a wide range of functions, including cell signaling, cell activation, proliferation, differentiation, and regulation of immune responses.
• Many cytokines have pleiotropic effects, meaning they can influence different cell types and have diverse biological activities.

Chemokines regulate the migration and positioning of immune cells. They induce chemotaxis, guiding immune cells to specific locations in the body.

Chemokines are crucial for the inflammatory response, recruiting immune cells to sites of infection or tissue damage.

• CSFs are a group of cytokines that regulate the production and differentiation of white blood cells (leukocytes) in the bone marrow, a process known as hematopoiesis.
• CSF encourage bone marrow to produce immature cells, or grow stem cells.

innate immunity

• skin
• mucous membranes
• secretions of skin and mucous membranes

• phagocytic leukocytes
• antimicrobial proteins
• inflammatory response
• fever

• adaptive immunity 
• lymphocytes
• antibodies
• memory cells

Epithelial Barriers:

• neutrophils and macrophages
• dendritic cells
• natural killer cells and intraepithelial lympthocytes

• Recognition of Pathogen-Associated Molecular Patterns (PAMPs): Innate immune cells recognize conserved molecular patterns on pathogens, triggering immune responses.
• Rapid Response: Pattern recognition allows for a quick and non-specific response to a wide range of pathogens.

• Cell Surface and Endosomal Receptors: Toll-like receptors (TLRs) are a family of receptors that recognize specific PAMPs, activating signaling pathways.
• Induction of Inflammatory Responses: TLR activation leads to the production of inflammatory cytokines and interferons.

• opsonins
• inflammatory cytokines
• acute phase proteins

• Complement Activation: The complement system consists of a series of proteins that, when activated, enhance immune responses by promoting phagocytosis, inflammation, and cell lysis.
• Opsonization and Membrane Attack Complex: Complement proteins can opsonize pathogens for phagocytosis and form the membrane attack complex, leading to the lysis of certain microorganisms.
• Chemotaxis
• It helps identify, target, and eliminate pathogens by promoting opsonization, inflammation, cell lysis, and the clearance of immune complexes.

• It is characterized by its specificity, memory, and ability to mount targeted responses against a wide array of pathogens. B cells, T cells, and the coordination of their activities with other immune cells play a central role in this highly specialized defense system.
• antigens

Antigens are molecules that can be recognized by the immune system, triggering an immune response.

Types: Antigens can be proteins, carbohydrates, lipids, or nucleic acids, often derived from pathogens or abnormal cells.

• lymphocytes
• major histocompatibility complex
• antigen presenting cells

• . Immunoglobulins:
• Antibodies: B cells produce immunoglobulins (antibodies) that recognize and bind to specific antigens.
• Classes of Antibodies: IgM, IgG, IgA, IgD, and IgE have distinct functions in immune responses.
• Humoral Immunity:

Antibody-Mediated Defense: Humoral immunity involves the production of antibodies that neutralize and eliminate extracellular pathogens.

• T Lymphocytes and Cellular Immunity:
• Helper T Cells and Cytokines in Adaptive Immunity:
• CD4+ T Cells: Helper T cells assist B cells(antibody) and cytotoxic T cells in immune responses.
• Cytokine Production: Helper T cells release cytokines to regulate immune cell activities.
• Regulatory T Cells:

• Immune Regulation: Regulatory T cells control immune responses, preventing excessive reactions and autoimmune responses, suppressing immune response.
• Cytotoxic T Cells:

• CD8+ T Cells: Cytotoxic T cells recognize and destroy infected or abnormal cells directly.
• Cell-Mediated Immunity:

Defense Against Intracellular Pathogens: Cellular immunity involves the direct action of immune cells, particularly against intracellular pathogens.

• thymus
• lymph nodes
• spleen
• secondary lymphoid tissues

• Active Immunity: Immunity acquired through exposure to an antigen, resulting in the production of memory cells.
• Passive Immunity: Temporary immunity conferred by receiving pre-formed antibodies or immune cells.

• Immune Tolerance: Mechanisms prevent the immune system from attacking the body's own cells (self-tolerance).
• Regulatory Cells: Regulatory T cells help maintain immune balance and prevent excessive responses.

primary and secondary antibody responses; activates complement; includes antibacterial, antivirals, and antitoxins; crosses placenta, creates passive immunity in newborns

primary antibody responses; activates complement; forms natural antibodies; involved in blood ABO incompatibility reactions

found in secretions such as tears and saliva, in mucous membranes, and in colostrum to provide protection for newborns

binds to mast cells in skin and mucous membranes; when linked to allergen, causes release of histamine and

: attached to B cells; activates B cells

• maternal antibodies
• b reast milk 
• colostrum

• immosenscence: aging
• thymic involution
• decreased immune vigalence
• vaccination
• inflammaging 
• adaptive immune memory