16. Immunology part 1 Flashcards
What is the immune system?
a network of specialised cells, tissues and soluble factors that co-operate to kill and eliminate cancer cells
What does the immune system do?
it can identify and eliminate microorganisms and other harmful substances as well as abnormal cancer cells
How does the immune system protect us from harmful substances/ cells?
- distinguishing self cells from ‘non-self’
- by identifying ‘danger’ signals e.g. from acute inflammation
- or via combination of the two
How is the immune system modulated for the basic of major advancements in the treatment of disease?
- vaccinations
2. immunosuppressants/ anti-inflammatory drugs
How do vaccines work?
by deliberately introducing of material derived from a pathogen to generate a tricked immune response to develop immunological memory so that in real life, if the pathogen was to invade, it would be recognised quickly
What do immunosuppressants do?
- essential for treatment in auto-immune diseases
2. key for preventing rejection of donor tissue in transplant recipients
How do we manipulate the immune system to prevent disease?
- immunisation
- anti-inflammatory and immunosurpressant drugs designed to suppress disease
- cancer immunotherapy
What does cancer immunotherapy allow?
enables the immune system to recognise, target and eliminate cancer cells, eking it a potential ‘universal answer’ to cancer
Why is there still an emergence of new disease?
- global village (travelling)
- population growth so more crowded environments
- changes in human behaviour (social environments contribute to spread of disease)
- changes in dynamics of other infections
- loss of natural habitat
- interactions with pathogens and humans
- zoonotic transfer e.g. COV-19 from animal to human host
What are the 2 types if immunity?
- innate immunity
2. adaptive immunity
What is innate immunity?
- first line of defence
- immediate
- non specific
- no memory
What is adaptive immunity?
- secondary
- needs time (days)
- specific
- memory
What are features of innate immunity?
- have natural/physical barriers
- soluble factors e.g. cytokines, acute phase proteins, inflammatory mediators, complement proteins
- immune cells; macrophages, mast cells, natural killer cells, neutrophils
What are features of adaptive immunity?
- soluble factors e.g. cytokines and antibodies
- immune cells e.g. T cells and B cells
What are innate immunity points of pathogen entry?
- digestive system
- respiratory system
- urogenital system
- skin damage
What are some routes of attack in innate immunity?
- circulatory system
- lymphatic system
What is the major innate immunity barrier? and what does it serve to do?
skin- a protective physical and chemical barrier which has an outer tough surface which is impermeable to micro-organisms
How does the respiratory epithelium act as a barrier?
is an inner surface bathed continuously in moving secretions e.g. mucous and acid
- goblet cells secrete mucous which trap pathogens and removes them from the body by cilia
What are commensal organisms?
have symbiotic relationship with host and usually at epithelial surfaces where they complete with pathogenic micro-organisms for resources
How important are commensal organisms?
- key in eradication of the normal flora with broad spectrum antibiotics commonly results in opportunistic infection
- organisms rapidly colonise an undefences ecological niche
e. g. - oral candidiasis after oral antibiotics
- vaginal candidiasis after oral antibiotics
- clostridium difficile infection after intravenous antibiotics
When are constitutive barriers less effective?
when breached or attenuated
How does our immune system protect us if barriers fail?
by specialised cells e.g.
- phagocytes (tissue and circulation)
- orchestrate initiation of response
- recognise, ingest and kill bacteria and yeasts - Degranulating cells (tissue and circulation)
- orchestrate initiation of response
- damage and kill multicellular parasites and viruses - Secreted proteins
- complement (induced)
- chemokines
- cytokines
Give some examples of phagocytic cells
- neutrophils, monocytes and macrophages, dendritic cells
Give some examples of degranulating cells
- mast cells, eosinophils and basophils
What happens in early innate immune responses?
- Tissue-resident innate immune cells recognise pathogens as ‘non-self’ and dangerous
- macrophages and mast cells come together to kill the pathogen and acute, local inflammation by sending out chemokine signals
What are features of macrophages?
- phagocytosis
- pro/ anti-inflammatory
- bacterial killing mechanisms
- antigen presentation
- wound healing/ tissue repair
What are features of mast cells?
- pro-inflammatory
- parasitic killing mechanisms
- linked to allergy and asthma
What do wound sites allow?
for pathogens to evade and establish infection
How do these cells recognise pathogens?
pathogens express PAMPS (pathogen associated molecular patterns) which are recognised by specific pattern recognition receptors (PRRs) that are expressed by immune cells
How do macrophages located and ingest extracellular bacteria?
by migrating through tissue to hunt down invading pathogens
