Immunology- intro Flashcards
what is immunology?
the study of the immune system and its responses to various insults
give 6 reasons why immunology is important/applicable
- defense against pathogens
- herd health (via serodiagnostics and vaccination)
- exaggerated or deficient responses (immune-mediated disease and immunodeficiences)
- cancer therapy
- grafts
- research tools
what are 5 hallmarks of the adaptive immune system?
- timing (activated later than innate)
- specificity
- diversity
- memory
- self vs nonself discrimination
what is the innate immune system?
the part of the immune system that is in place at birth, somewhat non-specific, and responds immediately to an offense, and is present in all animals
what are the 3 components of the innate immune system?
- physical/physiologic barriers
- antimicrobial molecules
- sentinal/phagocytoc cells
what are the 4 physical/physiologic barriers of the innate immune system?
- epithelium
- mucus/tears/sebum
- flushing/peristalsis
- commensal flora
how does epithelium act as a physical barrier in the innate immune system?
the stratified squamous epithelial layer has tight junctions to keep out pathogens from skin and is constantly sloughing old cells to remove potential pathogens
how do mucus/tears/sebum function in innate immunity?
- pH
- lysozyme
- bile
- pancreatic enzymes
how does flushing/peristalsis function in innate immunity?
cilia beat to clear the respirator tract of pathogens and the GI tract moves pathogens out via peristaltic contractions
what are two examples of antimicrobial substances and what are they produced by?
- defensins
- cathelicidins
produced by epithelial cells and leukocytes
describe how defensins and cathelicidins work
they are amphipathic and insert themselves into one half of the lipid bilayer, forming a pore that results in cell death bc cells don’t like having holes
what are 4 functions of the antimicrobial substances of the innate immune system?
- direct toxicity to bacteria, fungi, viruses, protozoa, enveloped viruses, and tumor cells
- activate/recruit leukocytes
- bind/neutralize lipopolysaccharides and microbial toxins
- stimulate wound healing and vascularization
what are opsonins?
extracellular molecules that bind to microbes and make microbes more susceptible to phagocytosis; an intersection of adaptive and innate immunity
give 2 types of opsonins
- complement proteins
- mucosal antibodies from IgM, IgA, and IgG
what are the 3 sentinel cells?
- mast cells
- macrophages
- dendritic cells
what do mast cells do? where are they located
located at blood vessels in tissues, secrete granules to initial inflammation
where are macrophages located? what do they do?
located in tissues, also kickstart inflammation (like mast cells) but also do phagocytosis
what do dendritic cells do?
process antigen to start adaptive response, basically pick up/phagocytose and then leave to coordinate additional efforts in the response
where do immune cells come from?
hematopoiesis that occurs in the bone marrow
what are the 3 categories of cells produced by hematopoiesis in the bone marrow?
- erythroid
- myeloid
- lymphoid
what are erythroid cells?
red blood cells
what are myeloid cells? (4)
- granulocytes
- mast cells
- monocytes/macrophages
- myeloid dendritic cells
what are lymphoid cells? (2)
- T and B cells
- natural killer cells (NK)
what is the ONLY self-renewing cell in bone marrow?
multipotential hematopoietic stem cells/ hemocytoblasts
at what point are cells committed to their path in bone marrow?
when they differentiate from multipotential hematopoietic cells to either common myeloid progenitor cells or common lymphoid progenitor cells
what cells comprise the major of innate immune cells as well as other cells?
those derived from common myeloid progenitor cells
what 11 cells derive from common myeloid progenitor cells?
- megakaryocytes
- thrombocytes
- erythrocytes
- mast cells
- myeloblasts
- basophils
- neutrophils
- eosinophils
- monocytes
- macrophages
- myeloid dendritic cells
what cells derive from common lymphoid progenitor cells? (4)
- natural killer cells (large granular lymphocytes)
- small lymphocytes (T and B cells)
- plasma cells
- lymphoid dendritic cells
describe where maturation of monocytes takes place
these cells are born in the bone marrow, and differentiate into monocytes, then migrate to lymphoid tissue or peripheral tissue where they are either activated to macrophages or differentiated to other cells
what are 4 cells types that monocytes can differentiate into?
- microglia
- kupffer cells in the liver
- alveloar macrophages in the lungs
- osteoclasts
describe maturation of dendritic cells
common dendritic cell precursors leave the bone marrow and migrate to the blood where they differentiate into either preconvential DCs or plasmacytoid Dcs, which will then enter lymphoid tissue or peripheral tissue and differentiate into conventional DCs or plasmacytoid DCs
where do lymphocytes develop?
bone marrow
where do lymphocytes mature?
the generative lymphoid organs
B cells: Bursa of Fabricius (bird), bone marrow (mammals)
T cells: thymus for everyone