General Items - Immunology - First Aid Flashcards
Purpose of medullary Sinus in LN?
Communicates with efferent lymphatics and contains reticular cells and macrophages
Where are the high endothelial venules in LN? What is their purpose?
In the paracortex. Its how T/B cells enter the LN from the blood.
Pathophysiology of Splenic dysfunction?
Decreased IgM –> decreased compliment activation –> decreased C3b opsonization –> increased susceptibility to encapsulated organisms
Encapsulated organisms?
SHiN SKiS: Strep. pneumoiae Influenzae Meningitidis Salmonella Klebsiella pneumoniae Group B Strep
Postsplenectomy a/w?
Howell-Jolly bodies (nuclear remnants, target cells, thrombocytosis
Hassall’s corpuscles
In medulla of Thymus
MHC I subtypes?
HLA-A, HLA-B, HLA-C
MHC antigen presentation mech?
Ag is loaded in RER with mostly intracellular peptides
MHC I and II molecular components?
1: alpha chain and b2-microglobulin
2: alpha chain and beta chain
MHC II subtypes?
HLA-DR, -DQ, -DP
MHC II antigen presentation mech?
Ag is loaded following release of invariant chain in an acidified endosome
How do NK cells function to kill?
Use perforin and granzymes to induce apoptosis in virally infected and tumor cells
What enhances NK cells?
IL-2, IL-12, IFN-B, IFN-a
When are NK cells induced to kill?
when exposed to nonspecific activation signal on target cell and/or to an absence of class I MHC on target cell surface
What is special about dendritic cells form other APCs?
Its the only one that can activate a naive T cell
Two signals required for Naive T cell activation?
MHC-TCR and B7-CD28
Two signals required for B cell activation and class switching?
MHC-TCR and CD40-CD40L
What proteins are in the cytotoxic granules of CD8 T cells? What is there function?
Perforin - Delivers contents of granules to target cell
Granzyme - activates apoptosis
Granulysin - antimicrobial
What surface markers are on Treg cells?
CD3, CD4, and CD25 (alpha chain of Il-2 receptor)
What do activated Treg cells secrete?
IL-10 and TGF-B
What region of Antibodies does complement bind to?
CH-2 (IgG and IgM only)
What are the mechanisms that generate Antibody diversity?
- Random recombination of VJ (light chain) and VDJ (heavy chain)
- Random combination of heavy and light chains
- Somatic hypermutation (following antigen stimulation)
- Addition of nucleotides to DNA during recombination by terminal deoxynucleotidyl transferase
What are the 3 mechanisms by which antibodies act?
Opsonization (–> phagocytosis), neutralization, and complement activation (–> opsonization, MAC)
What are thymus independent antigens?
Antigens that lack a peptide component –> cannot be presented by MHC to T cells –> stimulate release of Antibodies and do not result in immunologic memory
