Week 7 - Adaptive Immunity Flashcards
Advantages of the adaptive immune response
Specificity
Diversity
Memory
Self: non-self discrimination
Humoral immunity
Is mediated by B-lymphocytes and antibody associated with blood and body fluids
Targeting exogenous antigens produced by extracellular pathogens
Cell mediated immunity
Is mediated by t-lymphocytes targeting endogenous antigens in the intracellular space
Targeting viral infections and tumour cells
Active immunity
develops when host immune stystem generates the immune response to antigen challenge, it creates an immunological memory
Passive immunity
occurs when individuals receive preformed antibodies (artificially acquired) or from mother to child.
It only provides short term protection
What are the five major classes of antibodies
IgD, IgM, IgG, IgE, IgA
IgG
Persists for moths to years and is responsible for long term protection
IgM
First type of antibody produced after primary antigenic stimulation. Only lasts for short periods (weeks to months)
IgA
Found primarily in mucosal surfaces protection from invading pathogens
IgD
Present on the surface of B-cells and functions as an antigen receptor
IgE
Is involved in immunity to the helminth infections and allergic reactions
CD4+ T lymphocytes
T-helper cells - coach and trailer the immune response to a particular pathogen
They differentiate into distinct subtypes distinguished by the cytokines they produce
CD8+ T lymphocytes
Cytotoxic T cells - directly kill cells with viruses and intracellular bacteria and eliminate tumour cells
Mechanisms of CD8+
Granzyme - mediated killing
Fas-FasL - mediated killing
Primary immunodeficiency
Occurs when a part of the immune system is missing or functioning abnormally as a result of genetic change
Secondary immunodeficiency
Occurs as a result of infectious agents toxins or drugs
Examples of secondary immunodeficiency
HIV, diabetes, chronic kidney disease, leukaemia
Secondary immunodeficiency can be caused by
Acquired infections
Chronic diseases
Immunosuppressive therapy
Altered host physiology
Basic types of vaccines
Inactivated or killed
Live attenuated
Subunit
Toxoid
Inactivated or killed vaccines
Does not replicate in host - polio, influenza A, hepatitis A
Live attenuated vaccine
Replicates in host and stimulates immunity by does not cause disease - chicken pox, tuberculosis, measles, mumps, rubella
Subunit vaccine
Contains parts of microorganisms that are known to stimulate immunity - Hep B , Hib
Toxoid vaccine
Inactivated bacterial toxin that does not cause disease but stimulates immunity - diphtheria and tetanus
Immunological hypersensitivity reactions
Environmental substances
Infectious agents
Self antigens
Immediate hypersensitivity type 1
Allergy - mediated via mast cell degranulation and eosinophils in the innate immune system and IgE in the adaptive immune system
Antibody mediated hypersensitivity type 2
Cell bound antigen - mediated by complement and phagocytic cells in the innate immune system and IgG in the adaptive
Immediate
Immune complex disease (type 3)
Mediated by complement and neutrophils in the innate immune system and IgG in adaptive
Occurs within hours
Delayed hypersensitivity
Mediated via macrophages in the innate and T-lymphocytes in the adaptive
Onset 2-3days prior to exposure
What is the primary cause for autoimmune disease
Specificity for self-antigen
