Post-midterm Flashcards
Sulfamethoxazole
Blocks Dihydropteroate synthetase (PABA –> Dihydrofolic acid)
Cyclines (Tetra)
Inhibitors of protein synthesis.
Bind 30s and prevent attachment of aminoacyl tRNA unable to bind
eg. Doxycycline, tetracycline, minocycline
Aminoglycosides
Interfere with formation of 30S initiation complex, IRREV.
eg. “Mean” (amino) GNATS caNNOT kill anaerobes.
Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin
Bactericidal
Macrolides
Bind to 23 S component of 50S rRNA, blocking exit of peptide chain (translocation) (macroSLIDES). Bacteriostatic
eg. Azithromycin, clarithromycin, erythromycin
HLA haplotype associated with Graves, Addisions, and Sjogren’s syndrome
DR3. Increases RR of having the disease
HLA haplotype associated with rheumatoid arthritis
DR4, increases RR By 6
HLA haplotype associated with Type I diabetes
DQ2+DQ8, DQ6, DQ8 - 1 and 8 together has RR of 20.
HLA haplotype associated with ankylosing spondylitis
B27 (Class I HLA associated). RR of 87.4
HLA haplotype associated with Myasthenia Gravis
B8 (Class I HLA asosciated). RR of 3.
MHC Restriction
T cells can only recognize antigens on MHC class I and II if originate from same person. Peptides on foreign MHC molecules are not recognized.
CD 1
Family has 5 known members, located on chromosome 1. Closely related (looks like) to MHC I. CD1a, CD1b, CD1c - expressed on APCs and present lipid antigens to CD-1 specific T cells.
CD1d is expressed on wide spectrum of cells, and presents to NK-T cells
What cytokine can induce expression of Class II MHC molecules?
IFN y - can induce expression of MCH II on other cell types.
Cross presentation
One type of cell, DC, can present antigens of other, infected or dying, cells or cell fragments, and prime (or activate) naïve T lymphocytes specific for these antigens. Present on MHC I, and once CD8 T cells to CTLs, they kill infected host cells tumour cells without need for DCs.
Virus Evasion of MHC class I presentation - EBV Mechanism
EBV: proteasomal process inhibitors, and inhibits TAP-mediated peptide transport (both in MHC I process)
Virus Evasion of MHC Class I Presentation (HCMV, Human Cytomegalovirus mechanism)
Binds TAP in ER and inhibits peptide translocation, Competes for B2m and peptide (B2m is a subunit on MHC I, that is just there to maintain the 3d structure), Delays MHC class I egress from the ER, Binds MHC class I in the ER and prevents its egress, Ejects MHC class I molecules into the cytoplasm.
Viral Evasion of MHC CLass I Presentation - Herpesvirus
Ibhibits TAP mediated peptide transport.
LFA-1
Leukocyte function associated antigen 1 (integrin on T cell) - ligand on APCs is ICAM 1.
Is the major T cell integrin involved in APC binding.
CD28
Receptor on T cells, recognizes co-stimulatory protiens B7-1 (CD80) and B7-2 (CD86). Binding generates signals that work together with signals from TCR recognition of antigen presented by MHC on same APCs.
ICOS (inducible costimulator)
Related to CD28, also expressed on T cells – important in development and function of follicular helper T cells in GC responses. Costimulator molecule in T cell activation
CD 40 L (CD 154)
CD40L on antigen stimulated T cells binds CD40 on APCs and activates APCs to express more B7 co-stimulators and to secrete cytokines –> IL-12 –> enhance T cell differentiation
Ie CD40L-CD40 interaction, promotes T cell activation by making APCs better at simulating cells.
CTLA-4
LIke CD28, recognizes B7-1 and B7-2 on APCs. Induced in activated T cells, functions to terminate responses of these cells. Also important in suppressive function of Treg.
PD-1
Induced on activated T cells, recognizes different but structurally related ligands on many cell types. Function to terminate processes of activated T cells.
Cyclosporine
Inhibits calcineurin’s phosphatase activity, thus suppressing the NFAT-dependent production of cytokines by T cells. Widely used as an immunosuppressive drug to prevent graft rejection.
Rapamycin
Inhibits mTOR protein. mTOR stimulates protein translation, cell survival and growth of T cells. Related/similar to PI-3 kinase path. Used to treat graft rejection