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