Infection and Immunity Wk 8 - Lesson 62

What cell do APCs present antigens to?

T-helper lymphocytes

What cell does host infected cells and tumor cells present antigens to?

cytotoxic T-lymphocytes

What cell is a pro APC?

Dendritic cells

What cells are semi-pro APCs?

macrophages and B-lymphocytes

What is an effector cell?

cell type/stage of activation/maturity that can do something

What are examples of effector cells?

plasma cells are effector B-cells, activated CTLs, activated T-helper cells

What is the function of the plasma cells?

make antibodies

What is the function of activated CTLs?

kill host infected and tumor cells

What is the function of activated T-helper cells?

make cytokines and help other cells

What is the difference between MHC and MHC molecule?

MHC is the gene complex that codes for the MHC molecules

Why do MHC molecules have broad specificity?

they can present multiple different peptides but only one at a time; peptide must fit into the groove

What does the T-cell receptor bind to?

both the peptide and the MHC molecule

Why do T-cell receptors have unique specificity?

T-cells express one type of TCR, but many of them; all the TCR on a T-cell recognize the same peptide

What type of MHC do normal nucleated cells have and its importance?

MHC-I molecules but no peptide in it; important with transplantation because recipient body could recognize the donor MHC molecule as a foreign antigen

What are the two types of MHC molecules?

MHC-I, MHC-II

Which MHC molecule presents to T-helper cells?

MHC-II

What presenting cells use the MHC-II molecule?

dendritic cells, macrophages, B-cells

What is the source of peptides for MHC-II molecules?

extracellular proteins

What is the result of the MHC-II pathway?

T-helper cell produces cytokines which help B-cells and CTLs; ensures full B-cell activation and antibody production

What MHC molecule presents to CTLs?

MHC-I

What presenting cells use the MHC-I molecule?

infected host cell and tumor cells

What is the source of peptides for the MHC-I molecule?

proteins made inside the infected or tumor cell

Which adaptive immunity pathway will operate with an infection/vaccination?

both will operate but one will dominate

What does it mean if an animal has more MHC genetic diversity?

they can produce a greater number of different MHC molecules and thus can respond to more different antigens

What are all autoimmune diseases linked to in humans?

certain MHC alleles which can increase the humans risk for that disease

What can play a role in population survival?

expression of a sufficient number of different MHC genes

What molecules on T-helper cell and APCs need to bind?

CD4 on T-helper cell binds to MHC-II molecule on APC

What molecules on CTLs and host infected/tumor cells need to bind?

CD8 on CTLs binds to MHC-I molecule on host infected/tumor cell

What do B-cells need to do before presenting the antigen to T-helper cells?

bind antigen with BCR then internalize and process antigen before presenting it via MHC-II molecules

What do B-cells need in order to become plasma calls?

cytokine help from Th-cells; to get this help they need to present their unique antigen

What is identical to the B-cell receptor?

the antibody the B-cell makes; they both recognize the same antigen

What are plasma cells?

terminally differentiated cells; do not express BCR thus cannot act as an APC

What do B-cells result in?

clonal expansion, memory B-cells, plasma cells

What are the steps of activation of CTL effector cell?

first TCR binds Antigen on infected/tumor cell now can receive cytokine help from activated Th-cell

When microbe is in an extracellular space what is the innate response?

neutrophils, complement activation

When microbe is in an extracellular space what is the adaptive response?

antibodies

When microbe infects/replicates in host cells what is the innate response?

Natural killer cells

When microbe infects/replicates in host cells what is the adaptive response?

CTLs