Immunity & Inflammation Flashcards
Features of AIDS?
Pneumonia, nausea, diarrhoea, weight loss, meningitis, encephalitis, brain abscesses, neurological deteriroration, skin eruptions, lymphadenopathy, tumours
How is HIV spread?
Contaminated needle, sexual contact, mother-child ( placenta, childbirth, breast feeding)
WHat is AIDS?
HIV - RNA virus - enzyme reverse transcriptase inside host cells - transfroms viral RNA to DNA - new DNA (provirus) incorporated into host DNA - new copies of virus into tissue fluid & blood - infect Helper T cells - suppression of antibody mediated & cell mediated immunity - infections
What are the 2 classes of immunodeficiency?
Primary - genetically mediated
Secondary - acquired - protein deficiency, AIDS, bone marrow diseases, splenectomy, infection
What is myasthenia gravis?
Antibodies bind to & block acetylcholine receptors of neuromuscular junction - transmission of nerve impulses to muscle blocked - progressive muscle weakness - eyelid muscle, neck, limbs
What is autoimmune haemolytic anaemia?
Antibodies to antigens on RBC, destruction of RBC
What is Grave’s disease?
Antibodies to thyroid cells - stimulates glands - increased BMR, anxiety, restlessness, palpitations, warm sweaty skin, heat intolerance, diarrhoea
What is Hashimoto’s disease?
Antibodies against thyroglobulin & cells of thyroid - prevent T3 & T4 synthesis - hypothyroidism - decreased BMR, weight gain, depression, lethargy, dry cold skin, constipation
What is rheumatoid arthritis?
Antibodies to synovial membrane in ball & socket, hinge, & condyloid joints - Ig detected in blood - Ig + rheumatoid factor -chronicallly inflames joint , stiff, painful, swollen
What are examples of autoimmune disorders?
Rheumatoid arthiritis, Hashimoto’s disease, Grave’s disease, autoimmune haemolytic anaemia, myasthenia gravis
What are the stages of hypersensitivity?
- anaphylactic
- cytotoxic
- immune complex mediated
- delayed type
What is delayed type hypersenitivity?
Overreaction of T lymphocytes - antigen detected by memory t lymphocytes causes clonal expansion & large numbers of cytotoxic T lymphocytes released to eliminate antigen - damge to normal tissue e.g. skin graft rejection
What is immune complex mediates hypersensitivity?
Ag-Ab form insoluble complexes -usually bacterial toxins - broken down by complement and transported to spleen for destruction - problems iwth pagocytes - complexes deposited in tissue - kidneys, skin, joints, eye causin inflammation & tiisue damage - block glomeruli in kidney causing glomerlurinephritis
What is cytotoxic hypersensitivity?
Antibody reacts with antigen on cell surface - marked for destruction via complement activation, phagocytosis, antibody dependent cell mediated cytoxicity - usual process for bacteria, HDNB, transfusion reaction - ocuurs with IgM & IgG antibodies
What is anaphylactic hypersentivity?
Overproduction of IgE in response to allergen - mast cells & basophils have receptors for IgE - release granules of histamine (constricts smooth muscle - vasodilation & increased vascular permeability) - heart under severe pressure, bronchoconstriction & shock - eosinophils have a late response
Progression of hypersensitivity (Hay Fever).
IgE - mast cells -histamine
What is hypersensitivity?
Allergy - powerful immune response to allergen (non-harmful) - immune response = harmful
1st exposure - sensitised - subsequent exposure - exaggerated immune response
What are the 3 types of abnormal immune function?
Hypersensitivity, autoimmune disease, immunodefiency
What is latency?
M/O infect and remain dormant for many years - mycobacterium tuberculosis resides in macrophages in granulomas resume replication if immune system is compromised or repressed
HIV - dormant for up to 15 years
What is replication inside the host cells?
Plasmodium falciparum replicates in RBCs
Trinchinella replicates inside cysts
What is shedding of surface antigens?
Plasmodium parasite (malaria) - shed large quantities of surface antigens that bind to antibodies - block interaction with parasite
What is antigen masking?
Parasite worms coat themselves in host molecules - not recognised as foreign
What is antigenic variation?
HIV, influenza, & rhinovirus change surface antigens due to mutations - new strains - large changes result in pandemics as T & B memory cells don’t recognise antigens
What are examples of viruses that infect & destroy immune cells?
HIV - infects T cells
Epstein Barr virus - infects B cells
What are example of toxins that kill or inhibit immune cells?
Streptococcus - streptolysin kills neutrophils & inhibits chemotaxis
Leishmania prevents cytokine production by T cells
Viruses - toxin that downregualte inflammation
Examples of substances that degrade proteins of the immune system?
Menigococcus - enzymes that destroy antibodies
Herpes simplex virus & leishmania parasite - proteins that degrade complement
How do microorganisms evade the immune system?
Suppress immune system & evasion
How does the innate immune system recognise pathogens?
Viruses - nucleic acid in genome
Bacteria - flagellin
Fungus - mannan (oligosaccharide in cell wall)
How can past infection/immunity be tested?
Viral peptides - test antibodies in blood - agglutination (positive result) - DNA sequencing
What is passive artificial acquired immunity?
Antibodies processed in biopharma plants/ inoculated animals - prophylaxis to prevent worsening of disease
What can be given to preterm babies to raise their immune system?
Frozen (avoid immunoglobulin denaturation) breast milk donated - provides antibodies & nutrition (underdeveloped digestive system)
What is passive natural acquired immunity?
Via placenta & breast milk - lymphocytes not stimulated - immunity short lived until exposure
What is active artificial acquired immunity?
Vaccination - dead, live artificially weakened microbes, toxoids (inactive toxins) - retain antigens
What is active natural acquired immunity?
Illness (memory B cells formed) - subclinical infection (sufficient response for immunity but asymptomatic)
What is passive immunity?
Given antibodies - broken down - brief immunity
What is active immunity?
Individuals responds to antigen- lymphocytes activated - memory cells formed
What are the types of acquired immunity?
Active & passive (natural & artificial)
What are memory b cells?
Long-lasting - rapid response to repeat infection - stimulate plasma cells
What are plasma cells?
Secrete immunoglobulins - carried to tissue via blood - only react to one antigen - binds to target cell (neutalisation/agglutination) - binds to toxins, activate complement, attracts cytotoxic t cells & macrophages
What are the 2 type of B cells?
Plasma cells & Memory B cells
How does antibody mediated immunity differ from cell mediated immunity?
Don’t need APC - produce antibodies to detect & bind antigens
Where are B lymphocytes stored?
lymphoid tissue e.g. spleen & lymph node
What type of immunity do B lymphocytes cause?
Antibody Mediated/Humoral Immunity
What type of immunity do T lymphocytes cause?
Cell mediated immunity
What are helper T cells?
Produce cytokines (interleukins & interferons) which call immune cells - enable B cells to produce antibodies
What are suppressor T cells?
Inactivate T & B lymphocytes after initial immune response
What are cytotoxic T cells?
Inactivate cells carrying foreign antigens - attach & release toxins
What are memory T cells?
Long living cells - survive after infection - more rapid response to repeat infection
What are antigen presenting cells?
Macrophages that engulf foreign material and transport antigen fragments to T lymphocytes, APC destroyed & T lymphocytes sensitised to antigen
What are the 4 types of T lymphocytes?
Memory T cells, Cytotoxic T cells, Helper T cells, Suppressor T cells
What are B lymphocytes
Mature in bone marrow - produce immunoglobulins which bind to antigen - Antibody Mediated Immunity
What are T lymphocytes?
Mature in the thymus gland with a hormone called thymosin - 1 specific antigen - elicit specific immune response - Cell Mediated Immunity
What is the abundance of each type of lymphocytes?
70-80% T lymphocytes
20-30% B lymphocytes
How does the adaptive immunity differ from innate immunity?
Slower, specific, controlled by lymphocytes
What is SCID/ “Bubble Boy Syndrome”?
Absence of functional T-lymphocytes - defective antibody response - B&T lymphocytes don’t function due to non functional helper T lymphocytes
What are the effects of fibrosis?
1) Adhesions - fibrous tissue, may affect movement (peristalsis, loops of bowels)
2) Fibrosis of Infarcts - thrombi block blood vessels - infarction (tissue death due to starvation of blood supply) - varying degrees of organ damage
3) Tissue shrinkage - aging of fibrous tissue - may cause restriction of air passages, ureters, blood vessels
What is fibrosis?
Scar formation - fibrous tissue formed from granulation tissue - new capillaries & inflammatory material removed leaving behind collagen fibres (fibroblasts secrete this)
What disease can cause granulomas?
Tuberculosis (mycobacterium tuberculosis) - resistant to body’s defence - granulomas form in lungs
What cells are active in chronic inflammation?
Lymphocytes mainly - fibroblasts activate & lay down collagen (fibrosis) - inflamed site may be walled off to form granulomas (collection of immune cells)
What is chronic inflammation?
Causative agent cannot be removed - immune deficiency, m/o’s that evade initial immune response - similar symptoms to acute inflammation without resolution - wider scale tissue damage
What are the outcomes of acute inflammation?
Resolution (damaged cells removed - healthy tissue/scar tissue) & chronic inflammation
What is suppuration?
Pus formation - pus = dead phagocytes, dead cells, cell debris, fibrin, living & dead microbes - pyogenic (pus forming) bacteria = streptococcus pyogenes & staphylococcus aureus - small amounts form boils & large amounts form abscess
What is pain in inflammation?
Local swelling compresses sensory nerve endings - exacerbated by bradykinin & prostaglandins (chemical mediators that potentiate the sensitivity of the sensory nerve endings to pain stimuli) - promotes healing
What is pyrexia in inflammation?
Body temp rises - interleukins released from macrophages & granulocytes in response to infection - increase metabolic rate - increase need for oxygen & nutrients
What is pyrexia?
Increased core body temperature
What is chemotaxis?
Chemotaxins released from damaged cells, WBCs attracted to site of injury
Describe the migration of leucocytes in inflammation.
Neutrophils adhere to blood vessel linings via binding to adhesion molecules & squeezing between endothelial cells - phagocytosis
Macrophages - persist if issue not resolved (chronic) - live longer than neutrophils
Describe increased tissue fluid in inflammation.
Swelling of tissue (oedema) - leaking of fluid from blood vessels & enter interstitial spaces - prevents spread of infection - harmful (obstruct breathing & pain) & helpful (cushion joints & limit movement)
Describe increased blood flow in inflammation.
Arterioles & capillaries near the injured site dilate - dilatation caused by release of chemicals (histamine & serotonin) from damaged cells - provide more O2 & nutrients - increased temperature, redding, oedema
What are the overlapping actions of inflammation?
Increased blood flow, accumulation of tissue fluid, migration of leucocytes, increased core temp., pain & suppuration
What is acute inflammation?
Immediate response to cell injury - short duration - mild/severe reactions
What are the signs of acute inflammation?
- Redness
- Heat
- Pain
- Swelling
- Loss of function
What causes inflammation
Microbes & their toxins, physical agents (heat, cold mechanical injury, UV, radiation), & chemical agents ( weed killers, poisons, acids, alkalis)
What is the inflammatory response
Non-specific response to tissues damage - series of local events at cellular & tissue level - protective (isolates, inactivates & removes causative agent & damaged tissue) - removes causative agents, microbes, toxins, dead tissue & replaced with scar tissue or healthy tissue
What suffix indicates inflammatory disease?
Itis
Immunodeficiency disorders?
Severe combined immunodeficiency (SCID), temporary acquired immunodeficiency, & AIDS (HIV infection(
Limitations of innate immunity?
Pathogens can evade phagocytes & complement, immune response starts afresh if repeat infection occurs
What is immunological surveillance?
NK cells constantly patrol the body for abnormal cells - malignant/infected cells have unusual markers on membrane recognised by NK cells (reduction is major histocompatibility complex) - attempt to kill it - non-specific
What are examples of acute phase proteins?
Complement, C reactive protein, serum amyloid A, fibrinogen, anti-trypsin, caeruloplasmin, haptoglobins
What are acute phase proteins?
Liver produces in response to cytokines - causes fever & leucocytosis (increased WBC)
What is complement?
Plasma protein - binds to bacterial cell wall & stimulates phagocytosis & attract more phagocytes by chemotaxis
What are cytokines?
Proteins secreted by macrophages & T lymphocytes
What are interferons?
Produced by T lymphocytes & viral infected cells - prevent viral replication within infected cells & spread of virus to healthy cells
What is saliva?
Slightly acidic substances - antibacterial
What is lysozyme?
Bactericidal enzyme in mucous, sweat, tears
Where is HCL found?
Gastric juices
What are some natural antimicrobial substances?
HCL, lysozyme, saliva, interferons, cytokines, complement, acute phase proteins
What are eosinophils?
WBC - defence against parasites - granules of major basic protein (damage outer surface of parasite), cationic protein (neurotoxin affects parasite), peroxidase (produces hydrochlorus acid) - allergic reaction
What are basophils & mast cells?
Basophils (WBC) in blood & mast cells in tissue - discharge granules of histamine, heparin, chemotactic factors, & peroxidase - allergic reactions (asthma & peanuts)
What are macrophages?
Last for many years - phagocytose - secrete cytokines, hydrolytic acid & bactericidal substances into extracellular space - act as antigen presenting cell (APC)
What are monocytes?
Largest WBC - circulate in blood for 8 hours - enter tissue and differentiate into macrophages
What are neutrophils?
Arrive quickly at the site of infection - kill pathogens - move via chemotaxis - phagocytes allow neutrophils to engulf specific materials - dead neutrophils found in pus
What are phagocytes?
Macrophages in tissue, monocytes & neutrophils in blood
What is phagocytosis?
Cell eating - phagocytes move to infection/inflammation site via chemotaxis - pseudopodia engulf foreign substances - enzymes destroy invading organism - cytokines released to attract other cells
What cells are involved in innate immunity?
Neutrophils, eosinophils, basophils, tissue mast cells, monocytes in blood/macrophages in tissue, NK cells
How does sweat cause immunity?
Contain antibacterial and antifungal substances
How does nasal hair cause immunity?
Coarse filter - cilia in respiratory tract moves mucous containing microbes out of the throat via the mouth
How does mucous cause immunity?
Traps microbes
How does skin and the mucosa cause immunity?
Physical barrier to entry of substances
What defences exist at the body surface?
Skin, mucous, sweat, nasal hair
What are 5 types of non-specific immunity?
Defence at body surfaces, phagocytosis, natural antimicrobial defences, NK cells, inflammatory response
What is the specific immune system?
Specific to 1 invader - long term immunity against specific antigen - adaptive immunity
What is the non-specific defence system?
1st line of defence - prevents entry & inhibits further passage of microbes & foreign substances (proteins & chemicals) - quick & non-specific - innate immunity
What are the 2 types of defence mechanisms?
Specific & non-specific
What are the threats to the body?
Bacteria, viruses, parasites, fungi, protozoa, cancer cells, non-self cells (blood transfusion & transplantation)
What is the function of the immune system?
Protect the body from infection (caused by pathogens) & non-self bodies