Immuno - Tumor Immunity Review

drraythe's version from 2015-06-15 00:18


Question Answer
What are the three tumor-associated antigens?(1) Altered/new proteins
(2) Overexpression of a normal protein
(3) Express fetal protein
Which tumor-associated antigens are most likely to be immunogenic?Altered/new proteins are likely to be immunogenic, seen as foreign. Some fetal proteins may be seen as immunogenic
What is FOCMA?(Novel viral antigen - when starting to turn into cancer, shows this, Abs can find it) feline oncovirogenic assoc cell membrane Ag. On surface of T lympho cells of cats infected w/ FeLV. Coded by viral genome but NOT a part of virion
Innate response to tumor?**PRIMARY DEFENSE AGAINST TUMORS NK cells & macrophages
Acquired response to tumor cells? (3)(1) Cytotoxic T cell (sees MHC-1 of tumor + tumor antigenic peptide presentation)
(2) Antibody+Complement activation (leads to MAC & lysis of FREE tumor cells)
(3) ADCC (Antibody-Dependent Cell-Mediated Cytotoxicity) antibody alone provides little protection against solid tumor
Tumor invasion of the immune system - how does this happen? (In general)Tumor elim might select for tumor cells w/ immune system invading abilities making the condition worse in the future
Tumor invasion of the AQUIRED immune system - how does this happen?(1) Low immunogenicity
(2) Antigenic modulation/masking
(3) Tumor-induced immunosuppression
Explain low immunogenicity of tumor cellsDepressed MHC-1 expression/ costim molecules for T-cell activation might not be expressed
Explain antigenic modulation/masking of tumor cellsLoss of tumor antigen expression, degradation of antigen by antibody mediated endocytosis, blocking Abs may be produced (non-complement-activating-antibody may mask tumor antigens)
Explain tumor induced immunosuppressionTumor can produce factors that inhibit T-cells
Strategies to induce immunity to tumors(1) Nonspecific modulation of the immune response
(2) MoAbs (monoclonal antibodies)
(3) Expand (make more) antigen-specific T-cells
(4) Vaccination w/ tumor antigens
Explain nonspecific modulation of the immune responseActivate macrophages, stim cytokine release
Explain monoclonal antibodies (MoAbs) & how they induce immunity to tumors (3)(1) Make tumor-specific antibody, activates immune system
(2) Tumor specific antibody w/ toxin attached, when internalized kills cell
(3) Tumor specific antibody tagged w/ radionucleatide, binds to tumor & radiation kills it & its neighbors
Explain anti-tumor vaccines (3)(1) Vaccinate w/ tumor cells/antigens
(2) Vaccinate w/ plasmid/naked DNA transfected dendritic cells
(3) Vacc w/ cells transfected w/ genes for co-stim molecules/cytokines to enhance immune response to tumor antigens
When vaccinating w/ tumor cells/antigens, what are we hoping for?Cross-priming (CD4 & CD8 both primed)
If DNA injection, what is the DNA for?Tumor antigen
If injecting w/ transfected dendritic cells, what is important to know?MUST BE Pts DENDRITIC CELLS (MHC restriction)
If vacc with cells transfected with genes for co-stim molecules/cytokines to enhance immune response to tumor antigens, whats important to know?Has to be tumor cells from Pt
Explain nonspecific modulation. What do you do/what do we use?Nonspecific stim with BCG vacc. If you inject BCG into a tumor, it activates macrophages to release cytokines which then can bring in lymphocytes & NK cells
Explain the vaccine to treat canine melanoma. What kinda vacc is it?DNA VACC. Inject gene that codes to make human tyrosinase, which is similar to canine tyrosinase (enzyme expressed by replicating melanocytes). Human gene is expressed in dog & seen as foreign, then CROSS REACTION so dog immune system attacks the canine tyrosinase. NOT A CURE, just a delay, prolongs life of animal.
Does the canine melanoma vaccine cure them?Nope just extends time after tumor removal
Explain vaccine to treat canine non-Hodgkin’s lymphoma. What kinda vacc is it?"Cells based" vaccine, take pts B cells (APCs), load them with tumor proteins, inject them back into Pt