MICR Lecture 1 PDF

Chapter 1: Overview of the Immune System  A historical perspective of immunology What is immunity? Immunity is the state of protection against foreign pathogens or substances (antigens) Latin term immunis, meaning “exempt,” is the source of the English word immunity...

Chapter 1: Overview of the Immune System  A historical perspective of immunology What is immunity? Immunity is the state of protection against foreign pathogens or substances (antigens) Latin term immunis, meaning “exempt,” is the source of the English word immunity toknow need don't dates Observations of immunity go back over 2000 years Thucydides, an ancient historian, wrote in 430 BC of a plague in Athens where those who had recovered could safely nurse the currently ill  A historical perspective of immunology Can we generate immunity without inducing disease? YES…through vaccination gets immune system prepared Vaccination prepares the immune system to eradicate an infectious agent before it causes disease Widespread vaccine use has saved many lives immunesystemprimedbyvaccinesnsecondaryresponseisfasterstronger Examples: israbies vaccine and eradication of asmallpox, anthrax, aCOVID-19 What are other diseases that could be eradicated with a vaccine?  Practice question Herd immunity is: rate lower odisease loads f spread ofbeinginfected A) Vaccination of cows B) Vaccination or protection of a critical mass of people 0 C) Another term for innate immunity  Measles in the media Herd immunity: acquiring protective immunity in a critical mass of people through vaccination or recovery from infection, serves as a buffer for everyone elseprotectsothers  factors many in considered vaccine d evelopment Delivery? COVID-19 vaccine (2021) Global response Phase 3 Host response? Antibodies? Phase 1 Priority? Efficacy? Prolonged protection? Phase 2  A historical perspective of immunology Tcells Tlymphocytes BcellsBlymphocytes A portion of immunity involves both humoral and cellular components Humoral immunity combats pathogens via antibodies Bodies censsisarwayscantibodiesirunnycnumourai Antibodies are produced by ______ Bcells Passive _________ immunity vs. Active _________ immunity Cell-mediated immunity involves primarily ____________ ye These can eradicate pathogens, clear infected self-cells, or aid other cells in inducing immunity  Important concepts for understanding the mammalian immune response Humoral and cell-mediated immunity relies on surface receptors (B- and T-cell receptors) Receptors are randomly generated by gene segment rearrangements in B and T cells aka antigen p eptides that smh makes immune respond system B cells that encounter an Antigen _______ produce an _________ specific to the antigen Antibody T-cell receptors bind antigens or specific peptides presented by Antigen _________________ presentingcellsAPCs  bebacteriafungus could allergen  premature armor antibody anantigenibecomesaponesecretes antibodies d son surface asecreteacas aresuitor activation sequestered antigen oestrogen  r anana engursantigen anacesiton its s urface presents antigento anana transported passively response recognize antigens immune response over storm cytokine www.n.name cen m ediated numoura T-cell receptor Cytokine secretion Passive immunity Thymus Cell-mediated immunity B-cells Antigen B-cell receptor Lymphocyte Active immunity Antibodies T-cells Humoral immunity Bone marrow Serum  serumpiasmawitnoutcens Both Gresponsibierorantiboanatorinetransport Humoral immunity lymphocyte antigen Cell-mediated immunity serum Bcells atcells B cenreceptor icen receptor Bone marrow thymus antibodies secretion cytokine passive immunity active immunity  Important concepts for understanding the mammalian immune response pcanbeanantigeniencitsaresponse Pathogens fall into four major categories Viruses HBacteria yFungiFun Microbe vs. Pathogen? na r a me Parasitespottery responds todifferentpathogens differently Immune responses are quickly tailored to the type of organism involved and depend on the structure of the pathogen and itsAlocation, i.e., intra- or extra-cellular  Important concepts for understanding the mammalian immune response __________________ Pathogenrecognition : interaction between foreign organism and recognition molecule expressed by host cells Ligands _______ include whole pathogens,aantigenic fragments of pathogens, or products secreted by foreign organisms Ligand binding outcome = extra- or intracellular cascade of events leading to labeling and destruction of pathogen (immune response!) Cells that recognize and kill or engulf pathogen = ____________________ Cellularimmunity exantibody Soluble proteins for labeling and destruction of invaders = ____________________ Humouralimmunity  Important concepts for understanding the mammalian immune response Immune responses rely on recognition molecules Encoded in genomic DNA and always expressed (_________________________) Patternrecognitionreceptors Pres These bind to _________________________________ Pathogenassociatedmolecularpatterns (PAMPs)―generic molecules found on many different types of pathogens (e.g., peptidoglycan) Gmay toevade evolve immune system Randomly generated (B- and T-cell receptors) anairferentaantested These bind to very specific antigens, rather than generic molecules found on many pathogens  A historical perspective of immunology cel more ismade cen selected from p Clonal selection and generation of diversity Individual B and T cells each have an individual specificity for a single antigennanreceptorsonasinglebitcencodeforthesameantigeninapswibinaing This is due to each cell having many copies of a receptor on the surface that only binds to one type of antigen When a B or T cell interacts with its specific antigen, it is selected and becomesaactivated Activation results in a proliferation, producing a large number of clones Each clone is reactive against the antigen that initially stimulated the original lymphocyte  eoccurswnenareceptorisnotidea proliferation Borice Borton receptor Laoneamanaime Borton Gasnabeenactivateaget Borice bodycanprotectitsereveneurtner Can you think of any problems associated with generating random recognition receptors? autoimmuneresponses weak responses wasteofenergy  Important concepts for understanding the mammalian immune response ___________ Tolerance ensures that the immune system avoids destroying host tissue (_______________________) Selfnonselfrecognition Many of the random rearrangements used to create B- and T-cell receptors could be anti-self Tolerance helps to keep these anti-self recognition molecules/cells from circulating in the bloodstream Self-tolerance prohibits immune responses to host tissue maintained through elimination or inhibition of cells