Immunology/immunotherapy Flashcards
Describe the 3 phases of immunoediting.
- Elimination: removal of immunogenic tumor cells by immune system but less immunogenic cells can survive
- Equilibrium: tumor growth and immune destruction are equal
- Escape: tumor growth ensues due to decreased immunogenicity, immune suppression, and rapid tumor growth
Name 7 co-inhibitory checkpoint molecules.
- PD-1
- CTLA-4
- Lag3
- TIM-3
- VISTA
- BTLA
- B7-H3
Name 8 co-stimulatory checkpoint molecules.
- GITR
- CD28
- CD27
- OX40
- ICOS
- CD137
- CD122
- CD40L
PD-1 and CTLA-4 are expressed primarily on ________ and ______ while PD-L1 are expressed on _____ and ______.
- T cells and NK cells
- myeloid cells and some tumor cells
_____ is a monoclonal antibody that targets CTLA-4 and is used to treat ________.
Yervoy (Ipilimumab)
melanoma
Pembrolizumab (a.k.a. Keytruda) targets _______ and is used to treat _______.
PD-1
melanoma
Nivolumab (a.k.a. Opdivo) targets ______ and is used to treat ______.
PD-1
melanoma
Atezolizumab (a.k.a. Tecentriq) targets _______ and is used to treat _______.
PD-L1
urothelial cancer
Responses to patients with advanced, heavily pretreated tumors to checkpoint targeted therapies are reported in approximately ____% of patients.
20%
Monoclonal antibodies targeting checkpoint inhibitors are used for treatment of _____, _______, _____, and ______.
melanoma, head/neck cancer, bladder cancer, Hodgkin LSA
When ____ is expressed on tumors, it creates a local microenvironment rich in adenosine, which is immunosuppressive.
CD37
Indoleamine deoxygenase is a _______ molecule expressed locally by tumors and tumor-infiltrating myeloid cells.
highly immunosuppressive
Reduced expression of MHCII has been correlated with poor outcome in dogs with ________.
B cell LSA
MDSCs are released from bone marrow in response to cytokines released in inflammation, such as ____ and ______.
GM-CSF and IL-3
MDSCs can be recruited to TME by multiple chemokines, many of which are produced by the tumor during times of hypoxia, which is regulated by ______ production.
HIF-1a
MDSCs mechanism of immune suppression is through T-cell suppression through production of ____, ______ and ______ deprivation; production of ___ and _______ which stimulate Tregs and TAMs; downregulation of ________ production by TAMs which is a cytokine involved in T-cell activation; and _____ anergy.
- ROS
- arginase
- cysteine deprivation
- TGFB and IL-10
- IL-12
- NK cell
What is the classic Treg phenotype and other surface markers used for identification?
- classic: CD4+CD25+FoxP3+
- CTLA-4, GITR, Lag3, and folate receptor 4 (FR-4)
_____ and _____ are cytokines that can convert CD4+ T cells to Tregs.
IL-6 and TGFB
_____ is a chemokine that can recruit Tregs and ___ is a chemokine that can convert T cells to Tregs.
- CCR5
- CCL-1
______ and _____ can deplete canine Tregs.
Palladia and Cytoxan
A study showed the IDO1 expression in the tumor microenvironment led to _________ apoptosis.
increased DC apoptosis
Study in dogs with TVT showed that the tumor environment caused downregulation of _____ surface markers of activation and _____.
- DC and MHC
Possible mechanisms causing DC dysfunction include overexpression of the protein _____, accumulation of _______ in the DCs leading to decreased capacity to present antigen, and downregulation of ______ expression.
- S100A9
- triglycerides
- TLR9
______ and _____ are factors that negatively affect DC function.
IL-10 and VEGF
How can TNFa promote tumor progression?
- promotes tumor cell survival via induction of anti-apoptotic proteins
- promotes angiogenesis
- promotes metastasis
- hampers cytotoxic T-cell and macrophage responses
TGFB is what type of cytokine? How does it promote tumor progression?
- immunosuppressive cytokine
- stimulates Tregs and TAMs
- converts CD4+ T cells to Tregs
- inhibits effector T cells and activation of macs
What type of cytokine is IL-10? How does it promote tumor progression?
- immunosuppressive cytokine
- promotes Treg production/function
- stimulates TAMs
- Decreases DC and macrophage function
- inhibits production of inflammatory cytokines, IL-1, TNFa, and IL-12
How does IL-2 contribute to anti-tumor immunity?
- growth factor for T cells (including Tregs)
- enhances CTL and NK cytotoxicity
- produces LAK cells
- induces B cell proliferation
How does IFN-gamma contribute to anti-tumor immunity?
- promotes differentiation of naive CD4+ T cells to Th1 phenotype
- activates macrophages
- Increases MHCI/MHCII expression
IL-4 ______ MHCII expression.
upregulates
Currently, there are clinical trials looking at use of antibodies targeting other inhibitory checkpoint molecules, such as ___ and _____.
Lag3 and Tim3
There are studies evaluating costimulatory checkpoint molecules, such as ____, ____, and ____.
OX40, CD28, ICOS
What therapeutics can be used to deplete or inhibit MDSCs? There’s 10
- liposomal clodronate
- gemcitabine
- 5-FU
- sunitinib
- docetaxel
- COX-2 inhibitor
- KIT-specific Ab
- Vitamin D
- CXCR2 antagonist
- CXCR4 antagonist
What therapeutics can be used to promote maturation of MDSCs? There’s 5
- zoledronate
- ATRA
- docetaxel
- sunitinib
- decitabine
What therapeutics can be used to inhibit recruitment of MDSCs? There’s 2
- cFMS kinase inhibitor
- NSAIDs
What therapeutics can be used to block interactions of MDSCs? There’s 2
- anti-CD40 ab
- anti-PD-1/PD-L1 Ab
What therapeutics can be used to block function of MDSCs? There’s 4
- nitroaspirin
- arginase 1 inhibitor
- sildenafil
- triterpenoid
______ is the most well known and clinically used BRM.
BCG
BCG is derived by what bacteria?
Mycobacterium bovis
______ is a BRM that is instilled into bladder to treat non-invasive bladder TCC in people. Its MOA relates to the ability to elicit _____ inflammatory cytokines, a profile associated with inducing cytolytic cells to kill target tumor cells. This is in contrast to ____ response, which is anti-inflammatory.
- BCG
- Th1
- Th2
BCG has limited clinical use in dogs but has been evaluated in ______ and _______.
TVT and MCTs
In human and dog _______, Corynebacterium parvum has displayed anti-tumor activity as an adjunct to surgery.
melanoma
Using a mouse melanoma model, what species of Salmonella was able to slow tumor growth and specifically target primary tumor and metastatic lesions, independent of B and T cells?
Salmonella typhimurium
In a phase 1 clinical trial, VNP20009 (Salmonella typhimurium) was administered to dogs with a variety of malignant tumors. What were the DLTs and ORR?
- fever and vomiting
- 37%
MTP-PE is a __________ that when encapsulated (L-MTP-PE) can efficiently activate monocytes and macrophages to produce pro-inflammatory cytokines. Name the cytokines.
- NOD2 receptor agonist
- IL1b and IL1a, IL-6, IL-7, IL-8, IL-12, TNFa
Dogs treated with L-MTP-PE after limb amputation for appendicular OSA had improved survival time of ____ compared to placebo dogs of _____.
- MST w/ L-MTP-PE: 7 months
- MST w/ placebo: 3 months
Dogs treated with L-MTP-PE after limb amputation and cisplatin had a MST of _____ with ___% developing metastasis compared to dogs that received cisplatin alone with a MST of _____ and ___% developing metastasis.
L-MTP-PE after cisplatin:
- MST: 14 mo
- 73% developed mets
Cisplatin alone:
- MST: 10 mo
- 93% developed mets
Dogs treated with L-MTP-PE with splenectomy and chemotherapy for HSA had a MST of ____ compared to group receiving splenectomy and chemotherapy alone with a MST of _____.
L-MTP-PE + adjuvant chemo:
- MST: 9 mo
Adjuvant chemo alone:
- MST 6mo
Only dogs with stage I _____ that received L-MTP-PE had an increased survival over placebo treated dogs. No differences were observed with more advanced disease.
oral melanoma
CLDCs stimulate the immune system largely through induction of _____ activity and release of ____ and stimulation of the production of _____.
- NK cell
- IFN-gamma
- type 1 IFN
IV administration of modified CLDCs that encode IL-2 was performed in dogs with stage IV OSA. Treated dogs developed _______ and __________, indicating immune stimulation. Treatment was associated with increased survival times compared to historical controls.
- fevers and changes in leukogram
The ORR of dogs with STS treated with CLDC for 6 weeks was ____.
15%
The use of CLDCs has been evaluated in ______ and ______ in dogs.
metastatic OSA
STS
Modified adenovirus has been evaluated in dogs with _____.
OSA
Canine distemper virus has been evaluated for treatment in canine ________.
B and T cell LSA
Attenuated strain of Newcastle disease has been evaluated in vitro in human and canine ____ cells. When comparing cell death to PBMCs, they reported a ___% increased in cell death in canine cancer cells when compared to normal PBMCs.
- lymphoma
- 34%
Recombinant form of _______ (oncolytic virus) that expressed IFN-b and sodium iodide symporter (NIS) has been evaluated in dogs with various types of cancer, including LSA.
vesicular stomatitis virus (VSV)
CLDC contains CpG DNA, which can bind to ____.
TLR9
LPS is a ligand for _____.
TLR4
Imiquimod is a ______ agonist.
TLR7
IL-2 functions to induce clonal expansion of ____ cells in an antigen-specific fashion and activate ____, ____ and ____ cells. It also stimulates ____ cells.
- T-cells
- macs, DCs, and B cells
- NK cells
A study demonstrated the ability of IV recombinant human IL-2 to activate canine lymphocytes. What were the AEs?
mild GI toxicity despite high doses
A study evaluating an aerosolized formulation of IL-2 in dogs with primary lung cancer and with lung metastasis was performed. Complete regression was seen in ____% with pulmonary metastases. Assessment of lymphocytes obtained from BAL showed ________ 15 days after therapy.
- 50%
- increased cytolytic activity
IL-2 gene therapy using viral vectors has been evaluated in _____ and _____ and was shown to be safe and effective.
feline FSA and canine melanoma
IL-12 therapy has been evaluated in canine _____, ______, and ______.
head/neck tumors, TVT, MCTs
A study evaluating IL-12 electrogene therapy in dogs with mast cell tumors found a reduced tumor volume in ____% of patients and increases in intratumoral ____ and ______ effects.
- 82%
- IFN-gamma
- antiangiogenic
Explain why IL-15 therapy holds more promise over IL-2.
- Does not cause death of CD4+ T cells after prolonged periods of exposure but rather sustains T-cell proliferation
- play a critical role in CD8+ T cell memory formation and maintenance
- Does NOT play role in development of Tregs
IL-15 safety study was performed in non-human primates, and the DLT was ______.
neutropenia
Type 1 IFN’s affect cellular proliferation through interactions with cell cycle proteins ______ and ____ as well as induction of _____. They also have antiangiogenic properties through downregulation of _____ and _____.
- c-myc and Rb
- apoptosis
- VEGF and bFGF
Type 1 IFN’s are used successfully to treat _____, ______, and _____ in humans. In veterinary medicine, use is limited to _______.
- pediatric hemangiomas, RCC, and melanoma
- feline viral diseases
IFN-gamma (type 2 IFN) is an activator of _____ leading to increased antigen presentation, increased lysosomal function, and NO production. It can also increase __________ expression on a variety of cells, including tumors. IFN-gamma role in anti-tumor immunity is characterized by __________ and ______.
- macrophages
- MHC I and MHC II
- increased tumor cell lysis
- increased tumor antigen presentation to adaptive immune response
A safety study in cats with _____ using triple gene therapy that included IFN-gamma, IL-2, and GM-CSF was performed and found to be tolerable.
FSA
Whole tumor cell and tumor lysate vaccines have been evaluated in canine _____, _______, ________, and _____.
- HSA, melanoma, STS, B-cell LSA
A phase I/II study evaluating use of allogeneic HSA tumor lysate vaccine in combination with doxorubicin in dogs was performed. What were the AEs? The overall survival time of dogs receiving combo treatment were ___________ than chemo only treated historical controls.
- moderate diarrhea and anorexia
- sig better
Clinical trial of 16 dogs with _____ or ____ treated with autologous whole cell vaccine transfected with human GM-CSF was performed. Objective responses was seen in 3 dogs.
- melanoma or STSs
A study using human GM-CSF adjuvanted autologous vaccine looked at efficacy with B-cell LSA. Dogs in remission after a 19-week CHOP protocol were randomized to placebo or vaccine treatment groups. What were the findings?
no improvement in length of remission or overall survival
A phase II study investigating the use of an allogeneic melanoma vaccine in combo with xenogeneic melanoma protein, hpg100 was performed. The ORR was ___% and tumor control rate > 6 weeks was ___%.
- 17%
- 35%
The unmethylated dinucleotide CpG motifs present in high frequency in bacterial DNA (plasmid DNA vaccines) provide stimulation of _____, triggering them to induce ___-type immune response.
- DCs
- Th-1
ONCEPT for malignant melanoma in dogs uses ________ plasmids that contain the gene encoding _______.
- xenogeneic DNA plasmids
- human tyrosinase
A DNA plasmid vaccine against the dog _____ protein for use in B-cell LSA has demonstrated positive results when added to conventional chemotherapy.
- TERT
The most commonly used viral vaccine platform for both human and dog studies is the _______ family. This family is highly immunogeneic allowing strong immune responses against weak tumor antigens, such as _________.
- Poxviridae
- carcinoembryonic antigen (CEA)
In humans, one of the most commonly used viral vaccine platform is the ________.
canarypox virus ALVAC
Vaccination against tumor antigens using DCs can only be used ______.
autologously
The potency of DCs produced ex vivo for vaccination depends on the combination of cytokines used. DCs generated with ____ and ____ or ___ and ___ display potent priming of T-cell mediated immune responses in vitro,
- GM-CSF and IFNa or GM-CSF and IL-15
Immature DCs induce immune tolerance via expansion of ____ secreting T cells.
IL-10
A study in dogs with _____ showed that bone marrow derived DCs transduced with adenovirus expressing gp100 could be safely used.
oral melanoma
A recent study looked at the safety of using DC- ______ tumor cell fusion hybrid vaccine.
mammary
For monoclonal antibodies, -omab indicated ____ based, -ximab and zumab indicate _____ , and -umab indicates _____.
- omab: murine based
- ximab and zumab: chimeric
- umab: humanized
Cytopoint, a.k.a. ________, is a canonized antibody that targets canine ______.
- Lokivetmab
- IL-31
Immunocytokines target ________ and are linked to ____.
necrotic areas of tumor and linked to IL-12
A dose escalation study of an immunocytokine linked to IL-12 was performed in dogs with _______. It was found to be safely administered. IL-12 measured in serum correlated with an increase in systemic ____ levels. Increased ____ levels correlated with AEs.
- melanoma
- IL-10
- IFN-gamma
Transfer of lymphokine-activated killer cells is done by culturing PBMCs in high concentrations of ____, which selects for a population of cells with potent tumor cell lysis ability.
IL-2
When expanded with IL-2, _____ cells exhibit cytolytic activity that is many folds higher than LAK cells againist tumors.
TILs
______ is considered the best source of T cells for ACT.
TILs
A phase II canine clinical trial using autologous NK cells that were activated ex vivo for treatment of ____ is ongoing.
appendicular OSA
The use of _______ therapy has been used to eliminate MDSCs to enhance the tumor response to chemotherapy in dogs with _________.
- liposomal clodronate
- malignant histiocytosis
What is the key function that differentiates DCs from other APCs?
DCs can activate naive T cells
What are the 2 main types of MHC molecules and where are they expressed?
MHC class I molecules
- expressed on almost all cells
MHC class II molecules
- expressed primarily on APCs, such as macrophages, DCs, and B cells or can be induced to be expressed on cells only in case of inflammation
MHC I class molecules bind to what type of T cells?
CD8+ T cells
MHC class II molecules bind to what type of T cells?
CD4+ T cells
The exogenous antigen presenting pathway is the predominant pathway for _______ loading and occurs primarily in _______ cells.
- MHC class II molecule
- APCs
In the exogenous antigen presenting pathway, ______ acquires material from outside the cell by phagocytosis or receptor mediated endocytosis. The material is processed in an ________ by proteases and fuses with newly formed _________.
- APC
- endosome
- MHC II molecules
MHC class II molecules are produced in the _____. A chaperone protein (invariant chain) occupies the peptide binding groove, and as the complex leaves the Golgi apparatus, the invariant chain targets the complex to enter endosomal pathways where _________ digest the invariant chain to a small fragment, known as _____, which remains in the binding cleft. This complex then associates with proteins that release ____ allowing the groove to be occupied by foreign peptide. After peptide exchange, the complex shuttles to the cell membrane to be recognized by ________.
- endoplasmic reticulum
- proteases (cathepsins)
- CLIP
- CLIP
- CD4+ Th cells
_________ loading occurs in the endogenous antigen presenting pathway and occurs in ____ cells.
- MHC class I
- most cells
The endogenous pathway is responsible for immune recognition of _____ and ____ peptides.
- viral and self peptides
In the endogenous antigen presenting pathway, intrinsic protein is digested by _______ in the cytoplasm. These short fragments then enter the endoplasmic reticulum via _____ complex and are loaded onto empty MHC class I molecules held close to complex by ________. These molecules are then shuttled to the cell surface to be recognized by ________.
- proteosome
- TAP
- Tapasin
- CD8+ T cells
_________ is the term used when the structure of a proteosome is altered when exposed to inflammatory cytokines, such as IFN-gamma or TNF-alpha. It is more efficient at processing peptides with high binding efficiency to __________ peptide-binding cleft.
- Immunoproteosome
- MHC class I
Tumor proteins are processed and loaded onto MHC class I via the _______ pathway.
cross presentation
________ loading occurs in the cross presentation antigen presenting pathway and occurs primarily in _____ cells.
- MHC class I
- APCs
What antigen presenting pathway is critical for T cell activation?
Cross presentation pathway
The cross presentation antigen presenting pathway is same as endogenous pathway expect for what?
peptides come from environment
Maturation of APCs occurs by specialized cell surface receptors or intracellular receptors that recognize ______________.
pathogen associated molecular patterns (PAMPs)
TLR ligands include ______, _____, and _________.
viral/bacterial DNA, bacterial lipids, and endogenously derived molecules that alert immune system to tissue damage
TLR9 recognizes/binds to _______ which leads to production of ______ and ______.
- unmethylated CpG motifs
- IL-12 and TNFa
TLR7 is activated by what medication and leads to production of _______?
- imiquimod
- IFNa
Upon encounter with a maturation signal such as ligands for _____ family of molecules or ligation of the _______ molecule, immature DCs increase levels of costimulatory molecules and MHC and migrate to _______ where they can interact with and activate _______.
- TLR
- CD40
- local draining lymph node
- T cells
NOD-like receptors (NLRs) detect presence of _____ while RIG-like receptors (RLRs) detect presence of ______.
- bacteria
- viruses
NLR proteins sense bacterial products in the cytoplasm by interacting with C-terminal ________. This leads to a conformational change in NOD proteins which activates them and results in the recruitment of ____ through binding to caspase recruitment domains (CARDs). Activation results in de novo cytokine transcription via activation of _____ and ____ transcription factors and activation of IL-1 through _____ activity.
- leucine-rich repeats (LRR)
- CASP1
- NF-kB and AP1
- CASP1
Detection of viral RNA by RLRs leads to activation of _____ and ____, which induces inflammatory cytokines and ______ production by infected cell.
- NF-kB and interferon regulatory factor 3 (IRF3)
- type-1 interferon
Activated or mature DCs migrate out of peripheral tissue to _____. Monocytes and macrophages migrate in opposite pattern where they enter _______ and help in repair/clearance and activate _____ locally.
- LNs
- infected/damaged tissue
- T cells
B-cell receptor (BCR) binds in native form so that they detect _____________.
unprocessed antigens
T-cell receptor (TCR) can be composed of _____ and ____ chains or ____ and ____ chains.
- alpha and beta
- delta and gamma
alpha-beta TCR is present on ______ cells in the ______ and _____ organs whereas gamma-delta TCR is present in _____ and _____.
- majority of mature T cells in blood and lymphoid
- skin and intestines
Genomic splicing of TCR genes is dependent on ________.
recombinant activation gene recombinase (RAG recombinase)
The TCR alpha chain is comprised of ____ rearranged gene segments whereas the beta chain is comprised of ____ rearranged gene segments.
- 2
- 3
There is a large number of possible combinations of ___ in alpha chain and ____ in beta chain creating diversity among T cell population.
- VJ
- VDJ
The specificity of the TCR for a defined peptide bound in the groove of an MHC molecule is determined by regions of the TCR called __________. Interactions of this with peptide/MHC complex are a result of the combination of ___ chains expressed as well as the diversity generated by pairing ___ and ___ gene segments.
- complementary determining regions (CDRs)
- V
- VJ and VDJ
The TCR is associated with the dimeric proteins ____, ____ and ____, and together with alpha-beta TCR, they comprise the TCR complex.
- CD3δε
- CD3γε
- TCRζζ
The T cell response is divided into 3 phases, _____, ____, and ____.
activation (priming), expansion, and contraction
During priming (apart of the T cell response), a DC acquires antigen and matures at the site of infection then travels to a LN where it enters T-cell area and interacts with T-cell residents. An integrin receptor-ligand interaction occurs between ____ on T cell and ___ on DC. This interaction slows migration of DC past the naive T cells and helps bring the 2 cell membranes close together allowing MHC/TCR interaction.
- leukocyte function-associated antigen (LFA) - 1 and LFA-2
- ICAM
_____ is a molecule on T cells that leads to their activation and expansion via its interaction with its ligands expressed on mature DCs, ____ and _____.
- CD28
- CD80 (B7-1) and CD86 (B7-2)
Once CD28 on T cells bind to its ligand, it sends a signal to produce ____, which is a cytokine critical for T cell proliferation and survival.
IL-2
T-cell activation leads to increased expression of ____, which is expressed on CD4+ T cells. This is a ligand for the TNF family member ____ that’s present on surface of DCs. Binding of these molecules leads to upregulation of costimulatory molecules, cytokines, and increased DC surivival.
- CD154
- CD40
What are the 2 categories of memory T cells. Where are they found and what markers do they expression?
- T effector memory (T-EM) and T central memory (T-CM)
- T-EM are in nonlymphoid tissues, contain cytolytic granules and their expression is CD8+ CD62 low and CCR7-
T-CM cells are in secondary lymphoid tissues, do not contain cytolytic granules, and their expression is CCR7+ CD62L+
______ are specialized T cells left behind after a T-cell response has been cleared and the pathogen is gone.
Memory T cells (CD8+)
Maintenance of memory CD8+ cells is dependent on 2 cytokines: ____ and ____.
IL-7 and IL-15
Cytolytic granules contain molecules Perforin and proteases of the Granzyme family. ____ forms pores in target cell membrane allowing ____ to enter and cleave proteins inside the cell leading to apoptosis.
- Perforin
- Granzymes
The cytokine ____ induces a Th1 phenotype, which expresses the TF ____ leading to release of cytokines _____, ____, and ____. This leads to what type of response? Th1 cells also induce ___ production by APCs.
- IL-12
- T-BET
- IFN-gamma, TNF-alpha, and IL-2
- CTL response (cell mediated immunity)
- IL-12
The cytokine ____ induces a Th2 phenotype, which expresses TF ___, leading to release of cytokines ____, ____, ____, and ____. This leads to what type of response?
- IL-4
- GATA3
- IL-4, IL-5, IL-6, and IL-10
- humoral immunity, immunosuppressive
The cytokines ___ and ____induce a Th17 phenotype, which expresses TF _____, leading to release of cytokine ____. This leads to what type of response?
- IL-6 and TGFB
- ROR-gamma-t
- IL-17
- Tissue inflammation, autoimmunity
The cytokines ______ and ____ induce Tregs which express TF ____, leading to release of cytokines ____ and ___. This leads to what type of response?
- IL-10 and TGFB
- FoxP3
- IL-10 and TGFB
- Suppression of immunity
What are the 2 major sources of Tregs?
- nTreg: develops during thymic selection
- iTreg: originates from mature peripheral CD4+ T cells
What are the 2 inhibitory molecules that suppress T-cell activation?
CTLA-4 and PD-1
CTLA-4 is ______ after TCR engagement on T cells. It is constitutively found on ______ and competes with _____ for binding with ____ and _____.
- upregulated
- Tregs
- CD28
- CD80 and CD86
Clustering of CD80/86 on surface of APCs secondary to CTLA-4 sends signal to APC to activate ____, which metabolizes and depletes ___, inhibiting T-cell proliferation.
- IDO
- tryptophan
PD-1 is expressed on activated CD4+ and CD8+ T cells but is always expressed on ______. It has 2 known ligands. ______ has broad expression and is found on many nonhematopoietic cells and immune cells. It is also found on many tumors and correlates with ___ prognosis. ____ is mainly expressed on ____. Signaling through PD-1 blocks function and survival of ____.
- Tregs
- PD-L1 (B7-H1)
- Poor
- PD-L2
- effector T cells
Binding of PD-1 to its ligand leads to recruitment of SHP3 phosphatases which inactivate ____ cascade, blocking the production and secretion of molecules required for cytotoxic response.
- PI3k
List 5 ways Tregs suppress immune responses.
- directly kill T cells and APCs by producing Granzyme B
- Inhibit killing by CTLs by impairing granule exocytosis
- High levels of CTLA-4 on Tregs bind to CD8- and CD86 on APCS which causes increased intracellular levels of tryptophan metabolizing IDO which causes depletion of tryptophan and inhibits T cell proliferation
- Tregs express high levels of IL-2 receptor CD25, which bind to IL-2 more rapidly than other T cells limiting their growth
- Tregs secrete anti-inflammatory cytokines, such as IL-10 and TGFB
A low _________ ratio has been shown to be a negative prognostic factor for dogs with OSA.
- CD8/Treg ratio
A prospective study in 22 dogs with metastatic OSA were treated with Palladia. Circulating ____ increased with Palladia treatment but there was no effect on ____. ___% achieved stable disease. The PFS was _____, and the MST was ____.
- VEGF
- Tregs
- 18%
- PFS: 2 months
- MST: 3 months
T cells with high avidity to self peptides are either ____, undergo _____, or differentiate to ____.
- deleted
- anergy
- Tregs
______ are a type of TAA that harbor a mutation unique to an individual patient, but some mutations are common to a subset of patients. Give an example of this type of TAA.
- Mutation antigens
- BRAF mutation in melanoma
___-___% of human melanoma express a mutant form of BRAF where there is a ____ to ___ amino acid substitution at position ____.
- 40-60%
- valine to phenylalanine
- 600
Expression of cancer-testis TAA is restricted to tumor cells and normal _____ and _____ cells. Name some examples of this TAA.
- Placental trophoblasts and testicular germ cells
- MAGE-A3 in melanoma
- BAGE, GAGE, and NY-ESO-1 as well
______ are a type of TAA that are expressed on normal tissues and tumors derived from a particular tissue. Name some examples.
- Differentiation antigens
- Melan-A/MART-1 in melanoma
- gp100 (melanoma)
- tyrosinase (melanoma)
- CEA (colonic carcinoma)
- PSA (prostatic carcinoma)
______ are a type of TAA that are expressed on various normal tissues but have higher expression on tumor cells. Name some examples.
- Overexpressed TAAs
- Wilms tumor-1 (WT-1): breast and lung cancer
- HER2/neu in breast cancer
______ are a type of TAA expressed by tumors that are influenced by viral transformation.
Vital TAAs
Give an example of a post-transcriptionally modified TAA.
- MUC-1 protein is hypoglycosylated in ovarian cancer
_____ induces tolerogenic phenotype in DCs via downregulation of MHC class II, CD40, CD80, and CD86 and inhibition of IL-12, IFNa, and TNFa.
TGFB
TGFB signaling results in suppression of ____, ____, and ___ ligand on CTLs, and generation of iTregs.
granzyme A, granzyme B, and FAS ligand
List 4 mechanisms by which anti-tumor immunity can be inhibited.
- T cell deletion
- T cell anergy
- Negative regulatory cells/molecules
- Loss of TAA, downregulation of antigen-presenting molecules
FOXP3+ T cells are a negative prognostic factor in dogs with _________,
B cell LSA
What markers have been identified as MDSCs in the blood of dogs with cancer?
CD11b+CD14-MHCII-
BCG, IFNa, IL-2, imiquimod, and anti-CTLA-4 blockade are all examples of _______ immunotherapy.
non-specific
Vaccination with tumor-associated proteins, tumor-associates peptides, and irradiated tumor cells are all examples of _____ immunotherapy.
specific
Dendritic cell vaccines, Sipuleucel-T, T-cell clones, and TILs are all examples of ______ therapies.
adoptive cell
Describe 5 mechanisms of action of monoclonal antibodies.
- Bind specifically to target protein and block its function
- Trigger signaling downstream of target proteins
- Deliver toxins to cells expressing target protein
- Target cell lysis
- Bind to antigens expressed on apoptotic bodies eliciting T ell response through antigen presentation
Alemtuzumab targets _____ in CLL. What type of mAb?
CD52
Humanized IgG1
Bevacizumab targets _____ in colorectal cancer and lung cancer. What type of mAb?
VEGF
Humanized IgG1
Cetuximab targets _____ in colorectal cancer. What type of mAb?
EGFR
Chimeric IgG1
Gemtuzumab targets ____ in AML. What type of mAb?
CD33
Humanized IgG4
Ibritumomab tiuxetan targets ____ in NHL. What type of mAb?
CD20
Mouse
Ofatumumab targets ____ in CLL. What type of mAb?
CD20
Human IgG1
Panitumumab targets ____ in colorectal cancer. What type of mAb?
EGFR
Human IgG2
Rituximab targets ____ in NHL and CLL. What type of mAb?
CD20
Chimeric IgG1
Tositumomab targets ____ in NHL. What type of mAb?
CD20
Mouse
Trastuzumab targets _____ in breast cancer. What type of mAb?
HER2/neu
Humanized IgG1
A _____ antibody is generated by immunization of mice with human proteins and isolation of specific antibodies.
mouse
Chimeric antibodies are engineered to contain the variable Fv region from a ____ antibody and ____ constant Fc regions.
mouse
human
A humanized antibody derives its hypervariable region of the Fv from the _____ and the rest of the Fv and entire Fc from the _____.
mouse
human
______ antibodies are isolated from mice that have been engineered to express only human antibodies.
Human
Monoclonal antibodies can lead to lysis of cells via ______________ or _______________.
activation of complement protein cascade or antibody-dependent cell mediated cytotoxicity (ADCC)
Monoclonal antibodies initiate the complement cascade by binding to the ___ domain of IgG to _____ protein. This leads to cascade of cleavage of various complement system proteins which leads to formation of ______ on target (tumor cell) resulting in _____ formation and lysis of target cells.
- Fc
- complement protein
- membrane attack complex (MAC)
- pore
ADCC is initiated upon binding of ___ region of antibodies by _____ receptors. These receptors are expressed on various innate immune cell types, including ____ cells and activation leads to cytotoxic activity against target cells. What mAb has been shown to mediate antitumor activity via ADCC?
- Fc
- Fc receptors (FcRs)
- NK cells
- Trastuzumab
______ is a bispecific antibody that mediates regression of NH B cell LSA. It is specific for CD19 and CD3 (to recruit T cells)
Blinatumomab
Name 3 modified antibodies that deliver toxic molecules to tumor cells. Name the toxins.
- gemtuzumab: fused with ozogamicin
- Ibritumomab tiuxetan: fused with yttrium-90
- tositumomab: fused with I-131
IFNa can directly inhibit proliferation of ____.
T cells
IFNa has >90% response in _____. High-dose associated with severe toxicities in humans, including ____, ____, ___, and ____.
- hairy cell leukemia
- hypotension, vomiting, fever, and diarrhea
IFNa promotes _____ survival.
CD8+ T cell survival
High dose IL-2 in humans is associated with substantial toxicities, including _______,________, ______, and _____.
cardiac arrhythmia, capillary leak syndrome leading to hypotension, CNS toxicity leading to confusion, and GI toxicity (diarrhea)
The natural ligand for TLR7 is _____, which is present on some _____.
single stranded RNA
Viruses
TLR7 is expressed by many cell types including _____ and ______.
macrophages and DCs
Imiquimod is approved for use in __________ with a clearance rate of ___%.
basal cell carcinoma
75% or higher
Imiquimod induces proinflammatory mediators, such as ____, _____, and ____.
IFNa, TNFa, and IL-6
Imiquimod upregulates costimulatory molecules and chemokine receptors on ______, enhancing their function.
DCs
Name toxicities of imiquimod.
GI, avoid cat licking it off, immunosuppression (neutropenia), local erythema, elevated liver enzymes
High dose IL-2 therapy is an approved treatment for renal cell carcinoma and melanoma but clinical response for this therapy is only about ___% for both cancers
15%
An Oncept IL-2 for feline _____ was developed, which combined IL-2 with _____ virus.
- FSA
- Canarypox virus
Cats with FSA were treated with a combination of RT, surgery, and IL-2 recombinant canarypox virus vaccine. The median time to tumor recurrence was _____ compared to controls at _____. This treatment reduced the risk of relapse in the period from 6 months after start of treatment to after one year by ___% and after 2 years by ____%. What were the side effects?
- median time to recurrence w/ vaccine: 24 months
- without: 10 months
- 56%
- 65%
Side effects: short-lived apathy, hyperthermia, moderate skin reaction at the injection site
A CD40-B autologous cell-based vaccine was evaluated in dogs with B cell lymphoma in remission following induction chemotherapy. What were the findings?
- chemo + CD40-B vaccination did NOT improve TTP or lymphoma specific survival
- vaccination did potentiate effects of salvage therapy and improved rate of durable second remission
- vaccine was safe and found to synergize with chemo to improve outcome
CD40-B cells from healthy humans, healthy dogs and tumor-bearing dogs express increased levels of immune molecules such as ____ and _____. RNA-loaded CD40-B cells induce functional, antigen-specific ____ from healthy dogs and dogs with lymphoma.
- MHC and CCR7
- T-cells
In dogs, ___% of total lymphocytes in the blood are CD3+ cells, ____% are CD4+ cells, ___% are CD8 cells with equal distribution between CD8a and CD8b, and ___% are CD21 cells.
- CD3: 75%
- CD4: 44%
- CD8: 40%
- CD21: 28%
What is the most abundant lymphocyte in normal dog?
CD3+CD4+
What is the most abundant lymphocyte of the blood in normal human?
CD4+ T cells
What is the most abundant B cell in normal human? Which is followed by ____ then ____ B cells.
CD19+ B cells
Follicular B cells
Marginal zone B cells
Tregs represent ___% of lymphocytes in lymph node and spleen.
10%
IL-10 activates the JAK/STAT pathways. Upon binding, it recruits ____ and ___ to receptor complex and induces phosphorylation of receptors leading to transcription of IL-10 regulated genes.
- Tyk2 and JAK1
Maintenance of ____ signaling through STAT6 is important for FoxP3 mRNA expression and protein production in natural Tregs. This cytokine also induces the formation of iTregs from naive CD4+ T cells
IL-4
______ stimulates production of IgA antibodies by inducing B cells to switch to this phenotype and promotes tissue repair after local and inflammatory reactions subside.
TGFB
