Wh'Odilia? YOUdilia WHIINNNEEYYBURG Flashcards
Bacterial adherence is mediated by: (4)
pili, fimbrae, afimbrial adhesins, polysaccharide capsules
T/F: Antigenic variation in the surface structures of a pathogen is a form of immune evasion
TRUE: Allows pathogen to evade current specific immune responses by changing antigen being detected
T/F: Bacterial colonization of host mucosal surfaces by Shigella involves attachment and invasion
TRUE: contacts host surface and induces membrane ruffling –> internalization
T/F: NK cells are innate cells that engulf bacteria and kill them through release of granules containing perforin, granzymes and granulysin
FALSE: NK cells detect changes on cell surface of infected cells and kill infected host cells, not bacteria DIRECTLY
Phagocytosis:
Enhanced by opsonization
T/F: APC activate T and B lymphocytes
FALSE: APCs present antigens as peptides in MHC molecules recognised by T lymphocytes using T Cell receptors
CDF lymphocytes produce cytokines that help B to produce antibodies
B do not have a receptor that recognises MHC/peptide complexes presented on surface of APC and use antibody to recognise antigen
CD4 helper T cells
Provide help to B cells through CD40-CD40L interactions
Recognise MHC II
Mature into Th1 in lymphoid tissue
Do not express innate immune receptors
T/F: Antibodies are proteins that have multiple functions (3)
TRUE:
- Bind antigens through Fab fraction
- Bind complement using Fc fraction
- Bind to FcR through Fc fraction
CD4 helper 2 cells characterised by ability to produce:
IL4 and IL5
Leukocytes:
Stem cell:
- Common myeloid progenitor
a) Auxiliary cells: megakarocyte –> platelets, mast cell, basophil
b) Phagocytes: neutrophil, eosinophil, monocyte –>macrophage
c) dendritic cell - Common lymphoid progenitor:
a) NK cell
b) B cell –> Memory B, plasma
c) T cell –> effector T, Cytotoxic T, Memory T
PAMPS
Unique to microbes but shared within discrete taxonomic groups e.g. LPS
Recognised by special receptors of innate immune cells
TLR:
1&2, 2&6: surface lipoprotein 3: ds RNA 4: LPS 5: flagellin 7/8: ssRNA 9: CpG DNA 11: uropathogenic bacteria
NOD like receptors
Recognise peptidoglycan
Sensors of PAMPs and DAMPs
RIG like helicases
important in antiviral immunity
Collectins
proteins that bind carbohydrates
DAMPs
Can initiate and perpetuate immune response in noninfectious inflammatory response
Complement: (4)
- Opsonize
- mediate inflammatory responses
- activate B cell responses
- Kill through complement membrane attack
Cytokines: (2)
- Orchestrate immune responses
2. activate cells of adaptive immune system
Inflammasomes
Multiprotein oligomer: caspase 1, PYCARD, NALP and sometimes caspase 5(11)
Expressed in myeloid cells
Innate immune system
PROMOTES MATURATION OF INFLAMMATORY CYTOKINES IL1B, 1L-18
Shown to induce cell pyroptosis (programmed cell death associated with antimicrobial responses during inflammation)
NLRC4
Contains CARD domain + NBD + LRR to recruit procaspase-1 directly
Activated by bacteria e.g. Salmonella, legionella, pseudomonas
Inflammasome components:
NLR: sensor
NACHT: NLR oligomerisation
PYD: signal transduction, caspase recruitment
ASC domain: bridging or adaptor protein recruits pro-caspase 1