Cellular immune effectors Flashcards
how long lived are alveolar macrophages?
LONG-LIVED CELLS
where are alveolar macrophages found?
- resident within the lung
- specifically, in the LUMEN OF THE BRONCHI & ALVEOLI
what roles do alveolar macrophages have?
1) phagocytic
= white cells actively ingest & kill invading microbes
2) microbicidal functions
3) secrete inflammatory mediators
4) present microbial antigens to lymphocytes
how long lived are neutrophils?
SHORT-LIVED CELLS
what type of cells are they?
they are circulating white cells
what type of nucleus do neutrophils have?
multi-lobulated nucleus
what are neutrophils main function?
phagocytosis
- main role is to kill invading microbes, especially extracellular bacteria
what does the bone marrow do during an infection?
they reduce a large number of neutrophils, hence why the blood’s white cell count is increased
where do neutrophils migrate from and to during infection & inflammation?
they migrate from the blood to the site of infection/inflammation
what is the size of monocytes like compared to other circulating white cells?
monocles are the LARGEST CIRCULATING WHITE CELL
what is the nucleus of monocytes like and what function does the nucleus have?
- bean shapes/notched
- the nucleus replenishes & supports tissue macrophage populations
where do monocytes migrate to dying infection or inflammation?
they migrate to the lungs
what does the process of migrating to the lungs stimulate?
stimulates monocytes to mature into phagocytic macrophages or into dendritic cells
where are dendritic cells found?
within the MUCOSA OF THE LUNGS
what is their main role?
- NOT TO KILL MICROBES but to stimulate an adaptive immune response to infection
why do dendritic cells have long cellular extensions?
to sample airway content
where are mast cells found?
lung mucosa
what do mast cells bind to their surface?
they bind IgE antibodies to their surface
IgE = antibody central to allergic reactions
what is mast cells primary function?
central role in allergic reactions
what molecules do mast cells respond to and how do they recognise them?
- they respond to molecules that induce allergic responses
- they are recognised by cell-surface bound IgE
give 2 examples of inflammatory mediators that are released.
1) histamine
2) interleukin-2
what does the release of these mediators cause?
1) vasodilation
2) lymphocyte recruitment to the affected area
how common are eosinophils?
they are very uncommon white cells
where are eosinophils found?
found within the blood, lymph nodes, lymph tissue
in what way are eosinophils similar to mast cells?
they release histamine & Interleukin 4 when activated by antibodies
= degranulation
how else are eosinophils activated?
activated by chemokine eotaxin and RANTES
what is eosinophils central role?
killing parasites
- also have a central role in pathogenesis of asthma
what is the size of lymphocytes like?
they are relatively small
what is the nucleus and cytoplasm of lymphocytes like?
large nuclei
thin Layer of cytoplasm
where are lymphocytes found?
- blood
- spleen
- lymph nodes
- lymphoid associated tissue such as bronchus associated lymphoid tissue (BALT) bronchus
- sites of inflammation
what are 2 type of lymphocytes?
1) B cells
2) T cells
what do B cells differentiate into when activated?
- they differentiate into plasma cells & produce antibodies
what are T cells essential for?
they are essential for cell-mediated adaptive immunity & also many anitbody responses
what are the 2 main types of T cells?
1) CD8+ T cells
2) CD4+ T cells
what are CD8+ T cells?
cytotoxic cells that kill virus infected & tumour cells
what are CD4+ T cells?
they re further subdivided into Th1, Th2, Th7 subsets
what type of cells are natural killer cells & what do they do?
- they are lymphocytes
- they kill cells infected with viruses or other intracellular pathogens & tumour cells
