Intro to immunology Flashcards
Why do we need an immune system?
Protection against infectious organisms
Bacteria e.g. Staphylococcus, Streptococcus, mycobacteria
Viruses e.g. polio, influenza, HIV
Fungi e.g. Candida, aspergillus
Protozoans e.g. trypanosomes, malaria
Worms e.g. tapeworms, filaria
Protection against cancer
What are the 2 major systems of immunity?
- Innate immunity
- Adaptive immunity
What is innate immunity? (4)
“A first line of defence”
Present at birth
Responds rapidly
Has no specificity
Has no memory
compromises of barriers, cells, soluble factors
What are the 3 types of innate immunity barriers?
Physical barriers
- Impermeable outer surface
e. g. skin,epithelial cell layer lining mucosal surfaces - Cilia in nasal passages and bronchi
Chemical barriers
- Acidity in stomach
- Alkaline secretions
- Lysozyme in tears
Biological barriers
Competition with commensal organisms
What cells are involved in innate immunity?
Phagocytes - Monocytes, macrophages, neutrophils
NK cells - Kill tumour cells and virally-infected cells
Eosinophils - Attack and kill parasites
What are the soluble factors of innate immunity? (4)
Lysozyme
Complement
Cytokines particularly Interferons
Acute phase proteins
What is the Adaptive immune system?
Slow to start
Adaptive
Highly specific
Has memory
Recognition of self and non-self
Has Humoral and cellular components that work in concert
what is Humoral immunity ?
Humoral immunity is Antibodies (Immunoglobulins)
- Specific proteins produced against pathogens
- Produced by B lymphocytes
What is cellular immunity mediated by and what cells are involved?
Mediated by lymphocytes - which recognise antigens
cells involved:
B Lymphocytes
T Lymphocytes
Helper T cells (TH)
-help B cells produce antibodies
Cytotoxic T cells (TC)
-destroy own cells which have been
infected eg with virus
Graph showing primary and secondary immune response of disease
What are the 2 roles of the immune system?
Recognition function -
identifies a substance or body (antigen) as foreign (recognising self and non-self)
Effector function -
removes foreign invader
What is an antigen?
What is the portions of antigens recognised?
- Antigen = any substance which elicits an immune response
- Portion recognised = epitope or antigenic
determinant
What are Antigenic determinants are recognised by?
Antigenic determinants are recognised by:
Antibodies (humoral)
T cells (cellular)
but the two systems see different ones
What kind of molecules can antigens be?
(6)
Proteins
Carbohydrates
Nucleic acids
Lipids
Drugs eg penicillin
Inorganic molecules eg nickel
KEY POINT: ANTIGEN IS FOREIGN (non self)
