[LEC] MHC Flashcards
MOLECULES WITH THE GENETIC CAPABILITY TO MOUND AN IMMUNE RESPONSE
HLA
CLINICAL APPLICATION OF MHC
DETERMINE WHETHER TRANSPLANTED TISSUE IS HISTOCOMPATIBLE
BASIS OF ACCEPTANCE OR REJECTION OF TRANSPLANTS
DO MHC CELLS PLAY A ROLE IN HUMORAL OR CELLULAR IMMUNITY
BOTH
CAN MHC MOLECULES FUNCTION AS ANTIGENS
YES
FUNCTION OF MHC MOLECULES
TO BRING THE AG IN TO BODY TO THE CELL SURFACE FOR RECOGNITION BY T CELLS
WHEN WILL T CELL ACTIVATION OCCUR
WHN AG IS COMBINED WITH MHC MOLECULES ON THE SURFACE OF OTHER CELLS
GENES THAT ENCODE CELL-SURFACE MOLECULES
MHC
MOST POLYMORPHIC SYSTEM FOUN IN HUMANS
MHC
WHAT IS THE IMPORTANCE OF THE MHC’S POLYMORPHISM
ALLOWS FOR AN IMMUNE RESPONSE TO DIVERSE IMMUNOGENS
WHERE ARE GENES CODING FOR MHC MOLECULES LOCATED
SHORT ARM
CHROMOSOME 6
GENETIC LOCI OF THE CLASS I GENES
A
B
C
GENETIC LOCI OF THE CLASS II GENES
D REGION
DR
DQ
DP
HOW MANY GENES CODE FOR CLASS I MOLECULES
ONE
HOW MANY GENES CODE FOR CLASS II MOLECULES
1 FOR ALPHA CHAIN
1 OR MORE FOR BETA CHAIN
GENETIC LOCATION OF THE CLASS III GENES
BETWEEN CLASS I AND II ON CHROMOSOME 6
WHAT PROTEINS DO CLASS III GENES CODE FOR
C4A
C4B
C2
B COMPLEMENT
MHC CLASSES INVOLVES IN AG RECOGNITION
MHC I
MHC II
ALTERNATE FORMS OF A GENE
ALLELES
WHAT IS THE PROBABILITY OF ANY TWI INDIVIDUALS EXPRESSING THE SAME MHC MOLECULES
VERY LOW
[MHC CLASS I/II/III]
EXPRESSED ON ALL NUCLEATED CELLS
CLASS I
[MHC CLASS I/II/III]
EXPRESSED ON APCs
CLASS II
HIGHEST EXPRESSION OF CLASS I MHC ARE ON WHAT KIND OF CELLS
LYMPHOCYTES
MYELOID CELLS
LOWEST EXPRESSION OF CLASS I MHC ARE ON WHAT KIND OF CELLS
LIVER HEPATOCYTES
NEURAL CELLS
MUSCLE CELLS
SPERM
RATIONALE OF HLA MATCHING NOT BEING DONE IN CASES OF LIVER TRANSPLANTS
MHC CLASS I IS UNDER-EXPRESSED IN HEPATOCYTES
HLA AG THAT IS EXPRESSED IN LOW LEVELS
HLA-C
HLA AG MOST IMPORTANT FOR TRANSPLANTATION
HLA-A
HLA-B
POLYPEPTIDE CHAINS OF CLASS I MHC
ALPHA CHAIN
B2 MICROGLOBULIN
TRANSMEMBRANE DOMAINS OF THE ALPHA CHAIN
A1
A2
A3
LOCATION OF THE TRANSMEMBRANE DOMAINS
INSERTED INTO THE CELL MEMBRANE
CLASS I MHC CHAIN THAT DOES NOT PENETRATE INTO THE CELL MEMBRANE
B2 MICROGLOBULIN
CLASS I MHC CHAIN THAT PENETRATES INTO THE CELL MEMBRANE
ALPHA CHAINS
CONSTITUENTS OF THE CLASS I BINDING SITE
A1 AND A2 DOMAINS
They serve as the walls of the grove at the top of the molecule.
FUNCTION OF THE A1 AND A2 DOMAINS IN THE CLASS I MOLECULE
PEPTIDE-BINDING SITE
IN AG RECOGNITION
WHAT IS MORE SPECIFIC
A. Binding of peptides to T-cell receptors
B. Binding of peptides to Class I and II molecules
A. BINDING OF PEPTIDES TO T-CELL RECEPTORS
HIGHEST EXPRESSION OF CLASS II MHC ARE ON WHAT KIND OF CELLS
B LYMPHOCYTES
MONOCYTES
MACROPHAGES
DENDRITIC CELLS
THYMIC EPITHELIUM
MOST EFFECTIVE APCs
DENDRITIC CELLS
WHY ARE DENDRITIC CELLS THE MOST EFFECTIVE APCs
THEY HAVE THE HIGHEST LEVELS OF CLASS II MOLECULES ON THEIR SURFACES
MOST EXPRESSED CLASS II GENE
AND WHY
DR
IT ACCOUNTS FOR ABOUT 12 OF ALL THE CLASS II MOLECULES
AMOUNT OF MOST HIGHLY POLYMORPHIC CLASS II GENE
DR-BETA GENE
LEAST EXPRESSED CLASS II GENES
DP
WHAT IS THE FUNCTIONAL SIGNIFICANCE OF OPENED ENDS OF CLASS II PEPTIDE BINDING SITES
ALLOWS CLASS II MOLECULES TO CAPTURE LONGER PEPTIDES
(MORE THAN CLASS I MOLECULES)
NONCLASSICAL CLASS I GENES
HLA-E/F/G
NONCLASSICAL CLASS II GENES
DM/DN/DO
FUNCTION OF THE DM GENE
HELPS LOAD PEPTIDES ONTO CLASS II MOLECULES
FUNCTION OF DO GENES
MODULATES AG BINDING
FUNCTION OF DN GENES
UNKNOWN
MECHANISM OF AG PRESENTATION BY MHC MOLECULES
DEGRADED PEPTIDES WITHIN THE CELL ARE TRANSPORTED TO THE PLASMA MEMBRANE
T CELLS RECOGNIZE THE PEPTIDES AT THE PLASMA MEMBRANE WHEN COMBINED WITH MHC MOLECULES
WHY CAN THE BODY RESPOND TO MANNY DIFFERENT AG
EACH MHC MOLECULE CAN PRESENT A LARGE NUMBER OF DIFFERENT ANTIGENIC PEPTIDES TO T CELLS
TWO TYPES OF INFECTIOUS AGENTS
THOSE THAT ATTACK CELLS FROM THE INSIDE/OUTSIDE
WHAT T CELL DOES CLASS I MOLECULES PRESENT PEPTIDES TO
CD8 (CYTOTOXIC) T CELLS
WHAT T CELL DOES CLASS II MOLECULES PRESENT PEPTIDES TO
CD4 (HELPER) T CELLS
MHC MOLECULES THAT DEAL WITH ANTIGENS SYNTHESIZED WITHIN THE CELL
CLASS I
MHC MOLECULES THAT DEAL WITH ANTIGENS PRESENT OUTSIDE CELLS
CLASS II
REQUIREMENTS FOR A T-CELL RESPONSE TO BE TRIGGERED
ADEQUATE AMOUNT OF MHC MOLECULES
EFFECTIVE BINDING TO THE T CELL RECEPTOR
RECOGNITION BY THE T CELL RECEPTOR
EXAMPLES OF PATHOGENS THAT CAN BLOCK THE IMMUNE RESPONSE BY BLOCKING AG PRESENTATION
HERPES SIMPLEX VIRUS
ADENOVIRUS
CLASS III PROTEINS
COMPLEMENT
TNF-ALPHA AND BETA
OTHER PROTEINS NOT ASSOCIATED WITH MEMBRANE SURFACES
FUNCTION OF CLASS III MOECULES
COMPLEMENT ACTIVATION
OPSONIZATION
CHEMOTACTIC FACTOR GENERATION
