Genetics 9: Immunogenetics Flashcards
Complement System
Complement proteins perforate microbial cell membranes and attracts phagocytes/ immune cells
Immune system recognizes _______ in gram negatives
Lipopolysaccharides
Immune system recognizes _______ in gram positives
Peptidoglycan
T cells come from
Thymus
B cells come from
Bone marrow
Helper T cells
Stimulate killer T cells and B cells
Antigen presenting cells
Dendritic cells and macrophages
Engulf pathogens and then present them on their peptides on cell surfaces
MHC class II
Molecule that transports foreign peptide to surface. Carries it on specialized groove.
Co-stimulatory molecules
Presented on cell surface along with MHC class II to signal that foreign pathogens have been encountered
Cytokines
Signaling proteins that mediate cell communication
Immunoglobulin
Cell surface receptors of B cells that binds to peptides of pathogens
Somatic hypermutation
B cells that have succesful immunoglobulin binding produce more with DNA mutations to get even better binding
Plasma cells
B cells that bind to antigens for a long time rapidly divide and become plasma cells. Plasma cells secrete immunoglobulins to float around in blood stream.
MHC Class 1
Found on almost all human cells, binds with small peptides and displays to killer T cells. If the small peptide is foreign, it is not recognized and then the cytotoxic cell signals it to kill itself
Memory cells
Remain ready to fuck shit up should the antigen present itself again
Immunoglobulin composed of
Two heavy and two light chains
Immature b cells produce Ig__
IgM
Class switching
As B cells mature they begin producing IgG, IgA, IgE and IgD
Constant region of immunoglobulin is at ________ terminal
(C) Carboxyl-terminal
Variable region located at ___________ terminal
(N) amino-terminal
Constant region determines
Class of Ig moleculte (e.g IgA, IgM, IgE etc)
Recombinase
Initiate double strand DNA breaks at specific DNA sequences flanking V and D segments. This leads to different combos of Ig molecules
Somatic recombination
Recombination of DNA to produces different Ig molecules
Affinity maturation
When Ig molecules cells recognize antigen, the cells producing them replaces cytosine with uracil to cause errors to DNA so new, slightly mutated antigens can be produced
Natural Killer cell immunoglobulins mhc activity
Inhibit natural killer cells when binding to MHC class 1 but activate when MHC 1 is missing
Cross reaction immune response
After infection, antigens from invaders (E.g. klebsiella) are similar to human antigens and are recognized by immune system which then causes self recognizing cells to proliferate and cause damage
Adenosine deaminase (ADA) deficiency
Autosomal recessive disorder of purine metabolism resulting in metabolites toxic to immune cells. Causes SCID
Chronic granulomatous disease
Phagocytes ingest bacteria and fungi but dont kill them. Results in granulomas
Wiskott-Aldrich syndrome
X-linked recessive disorder that causes progressive T-cell dysfunction.
SCID treatment
Bone marrow transplant, gene therapy
X-linked agammaglobulinemia (XLA)
Lack B cells. Initially due to maternal antibodies have immune response but when supply dwindles, treament is needed. Treated with large amounts of Gamma globulin
SCID biggest cause
x-linked recessive mutation that encodes gamma chain found in cytokine receptors. Without these, T cells cannot mature
