Mitzi Nagarkatti, PhDMitzi Nagarkatti, PhDProfessor and Chair Professor and Chair

Dept. of Pathology, Microbiology and ImmunologyDept. of Pathology, Microbiology and ImmunologySchool of MedicineSchool of Medicine

andandDeputy Director, Basic and Translational Research Deputy Director, Basic and Translational Research

South Carolina Cancer CenterSouth Carolina Cancer CenterUniversity of South CarolinaUniversity of South Carolina

Tel. # (803)733-3275Tel. # (803)733-3275E-mail: mnagark@uscmed.sc.eduE-mail: mnagark@uscmed.sc.edu

Tumor Immunology

ObjectivesObjectives

IntroductionIntroduction Ags expressed by cancer cellsAgs expressed by cancer cells Nature of immune responseNature of immune response How cancer evades immune How cancer evades immune

systemsystem ImmunotherapyImmunotherapy

Cancer Introduction

Cancer Introduction

Uncontrolled growth produces a tumor or Uncontrolled growth produces a tumor or neoplasm.neoplasm.

A tumor that grows indefinitely and often A tumor that grows indefinitely and often spreads (metastasis) is called spreads (metastasis) is called malignantmalignant----also called cancer.also called cancer.

A tumor that is not capable of indefinite A tumor that is not capable of indefinite growth----growth----benign.benign.

Malignant---kills host.Malignant---kills host. Benign---does not kill host.Benign---does not kill host.

Cell GrowthCell Growth

Control of cell growth

Growth-promotingProto-oncogenes

Growth-restrictingTumor-suppressor genes

Molecular Basis of CancerMolecular Basis of Cancer

Uncontrolled cell growth

Proto-oncogenesTumor-suppressor genes

MutationsRadiationChemical (Carcinogen)Virus

Types of cancers based on etiologic agentTypes of cancers based on etiologic agent Chemically-induced tumorsChemically-induced tumors

Each tumor induced by a carcinogen (e.g. benzopyrene) Each tumor induced by a carcinogen (e.g. benzopyrene) injected at various sites expresses a unique Ag.injected at various sites expresses a unique Ag.

Thus difficult to develop vaccine.Thus difficult to develop vaccine.

Virus-induced tumorsVirus-induced tumors Tumors induced by same virus express same tumor Ag.Tumors induced by same virus express same tumor Ag. Induce a strong immune response.Induce a strong immune response.

e.g. Gardasil vaccine – Human Papilloma Virus (HPV) e.g. Gardasil vaccine – Human Papilloma Virus (HPV) induced cervical cancerinduced cervical cancer

UV-induced tumorsUV-induced tumors UV radiation--->melanomasUV radiation--->melanomas Highly tumorigenicHighly tumorigenic

Virus-induced tumors e.g.SV40

Chemical-induced tumors e.g. methylcholanthrene

Types of Cancer based on the tissue affectedTypes of Cancer based on the tissue affected CarcinomaCarcinoma: Cancer of endo or ectoderm : Cancer of endo or ectoderm

e.g. Skin or epithelial lining of organse.g. Skin or epithelial lining of organs SarcomasSarcomas: Cancer of mesoderm e.g. bone: Cancer of mesoderm e.g. bone Leukemias and LymphomasLeukemias and Lymphomas: Cancers of : Cancers of

hematopoietic cellshematopoietic cells

Evidence for the role of immune system in tumor rejection

Evidence for the role of immune system in tumor rejection

Spontaneous regressionSpontaneous regression Infiltration of tumors by lymphocytes and Infiltration of tumors by lymphocytes and

macrophagesmacrophages Regression of metastases after removal of Regression of metastases after removal of

primary tumorprimary tumor Regression after chemotherapyRegression after chemotherapy Lymphocyte proliferation in draining lymph Lymphocyte proliferation in draining lymph

nodesnodes Higher incidence of cancer after Higher incidence of cancer after

immunosuppression/immunodeficiency immunosuppression/immunodeficiency (AIDS, neonates, aged, transplant patients)(AIDS, neonates, aged, transplant patients)

Antigens expressed on tumor cellsAntigens expressed on tumor cells

Major HistocompatabilityComplex antigens

TSTA

TATA

TSTA: unique to a tumor Play an important role in tumor rejection.TATA: shared by normal and tumor cells

Tumor-associated developmental Ag (TADA)Tumor-associated viral Ag (TAVA)

Tumor-specific transplantation AgTumor-associatedtransplantation Ag

Tumor-Associated Developmental AgsTumor-Associated Developmental Ags

Found on cancer cells and on fetal cells.Found on cancer cells and on fetal cells. Do not trigger anti-tumor immunity.Do not trigger anti-tumor immunity. Used in diagnosis.Used in diagnosis.

Alpha-fetoprotein(AFP) Cancers of liverAlpha-fetoprotein(AFP) Cancers of liver Carcinoembryonic Ag (CEA) colorectal Carcinoembryonic Ag (CEA) colorectal

cancercancer

Other Tumor associated antigensOther Tumor associated antigens Differentiation Ags: B cells produce surface Ig. Differentiation Ags: B cells produce surface Ig.

B cell tumors have sIgB cell tumors have sIg

Melanomas and melanocytes express MART-1Melanomas and melanocytes express MART-1 Overexpression of Ag on tumors compared to Overexpression of Ag on tumors compared to

normal cells e.g. In breast cancer, HER2/neunormal cells e.g. In breast cancer, HER2/neu Ags expressed on male germ cells and melanoma Ags expressed on male germ cells and melanoma

e.g. MAGE-1e.g. MAGE-1

Syngeneic(accepted)

Allogeneic(rejected)

Inbred: repeated brother-sister matings

Outbred:normal population

Xenogeneic(rejected)

Tumor Growth

Across SpeciesRat

Mouse

How does a tumor escape immune surveillance?How does a tumor escape immune surveillance?

Generation of Regulatory cells (CD4Generation of Regulatory cells (CD4+CD25CD25+ FoxP3 FoxP3+ T T cells) or Myeloid-derived suppressor cells(Gr-1cells) or Myeloid-derived suppressor cells(Gr-1+ + CD11bCD11b++))

Secrete immunosuppressive molecules Ex: Secrete immunosuppressive molecules Ex: Transforming growth factor beta (TGF-Transforming growth factor beta (TGF-), interleukin-), interleukin-10 (IL-10), etc.10 (IL-10), etc.

Tumor

T regs

MDSC

CTL

IL-10, etc

Failure to process and present tumor Ag.Failure to process and present tumor Ag.

tumor

Macrophage

T helper (Th) cell

B cell

Cytotoxic T lymphocyte (CTL)

tumor Ag tumor

tumor

MHC Class I

MHC Class II

Tumors escape the action of CTL by not expressing B7 which provides 2nd signal involved in T cell activation

tumor

CTL

tumor Ag

Class I MHC

B7

CD28

Tumors may fail to express costimulatory Tumors may fail to express costimulatory

molecules involved in T cell activation.molecules involved in T cell activation.

Downregulation of MHC expression on Downregulation of MHC expression on tumor cell (CTL resistant but NK tumor cell (CTL resistant but NK sensitive)sensitive)

NK cellTumor

cell

Tumor escape mechanisms:Tumor escape mechanisms:Fas FasL

TumorCTL

FasFasL

TumorCTL

When tumor cells express Fas Ligand,they can kill Fas+ T cells, thereby escapingimmune destruction.

Surgery Surgery Radiation ChemotherapyRadiation Chemotherapy

Localized tumors Metastastic tumorsAffects proliferating cells

(bone marrow, etc.) Radiation/Drug-resistant tumors

Novel Mode: Immunotherapy

Traditional approaches to treat cancer

ImmunotherapyImmunotherapy Active ImmunizationActive Immunization: The host actively elicits : The host actively elicits

an immune response. an immune response. SpecificSpecific

Vaccination with viral Ags: e.g.Vaccination with viral Ags: e.g. Hepatitis B virusHepatitis B virus Human Papilloma virus (HPV) - Human Papilloma virus (HPV) -

GardasilGardasil

NonspecificNonspecific:: BCG (Bacillus Calmette-Guerin) BCG (Bacillus Calmette-Guerin)

Mycobacteria - melanoma, bladder Mycobacteria - melanoma, bladder carcinomacarcinoma

Normal M

Tumor

Activated M

Tumor lysis

Passive ImmunizationPassive Immunization: Preformed Abs or immune : Preformed Abs or immune cells transferredcells transferred Specific:Specific: Ab Therapy Ab Therapy

Abs against growth factor receptor e.g. IL-2R Abs against growth factor receptor e.g. IL-2R in HTLV-1 induced Adult T cell leukemiain HTLV-1 induced Adult T cell leukemia

Abs specific for oncogene product e.g. Abs Abs specific for oncogene product e.g. Abs against HER2/against HER2/neu (neu (Herceptin or trastuzumab)Herceptin or trastuzumab)

IL-2R

IL-2

Anti-IL-2R

Monoclonal Abs used in Immunotherapy

Monoclonal Abs used in Immunotherapy

Unlabelled Ab: e.g. Anti-CD20 Ab in Unlabelled Ab: e.g. Anti-CD20 Ab in non-Hodgkin’s lymphoma non-Hodgkin’s lymphoma

Complement (C’)Complement (C’) Ab-dependent cell mediated Ab-dependent cell mediated

cytotoxicity (ADCC)cytotoxicity (ADCC) Labelled Ab (Radioisotope/Toxin)Labelled Ab (Radioisotope/Toxin)

131131I (Iodine)I (Iodine) InternalizationInternalization

B cell tumor

C’

M/NK/PMN

CD20

FcR

Anti-tumor Abs coupled to toxin, Anti-tumor Abs coupled to toxin, radioisotopes, drugs or enzymesradioisotopes, drugs or enzymes::

ImmunotoxinsImmunotoxins: : Ricin A/diphtheria/Pseudomonas Ricin A/diphtheria/Pseudomonas toxin coupled to Abs. e.g. antiCD20-toxin coupled to Abs. e.g. antiCD20-Pseudomonas toxin in B cell Pseudomonas toxin in B cell leukemia leukemia Internalized toxin inhibits protein Internalized toxin inhibits protein synthesis.synthesis.Cytocidal isotopes or anticancer Cytocidal isotopes or anticancer drugs (adriamycin) coupled to Absdrugs (adriamycin) coupled to Abs

TumorRicin

Adoptive ImmunotherapyAdoptive Immunotherapy

1. 1. Lymphokine-activated killer cells Lymphokine-activated killer cells (LAK): (LAK): Peripheral Blood Lymphocyte (PBL) + Peripheral Blood Lymphocyte (PBL) + high dose IL-2high dose IL-2

NK/TNK/T LAKLAK

2. 2. Tumor-infiltrating lymphocytes Tumor-infiltrating lymphocytes (TIL): (TIL):

In and around solid tumorsIn and around solid tumors

Activated NK and CTLActivated NK and CTL

1)Use of LAK cells + IL-2 to treat cancer1)Use of LAK cells + IL-2 to treat cancer

Isolate lymphocytes from blood

lymphocytes

+IL-2 for 3 days

IL-2

LAKcells

melanoma

Treatment of Melanoma with LAK cells +IL-2

Treatment of Melanoma with LAK cells +IL-2

Before After

2) Use of tumor-infiltrating lymphocytes + IL-2 to treat cancer2) Use of tumor-infiltrating lymphocytes + IL-2 to treat cancer

surgical removalof cancer nodule

tumor

T cell

+IL-2

IL-2

Successful treatment of melanoma and renal cell carcinoma

Treatment of Melanomas with TIL + IL-2

Treatment of Melanomas with TIL + IL-2

Before After

Dendritic CellsDendritic Cells Highly potent antigen processing and Highly potent antigen processing and

presenting cellspresenting cells Prime an Immune ResponsePrime an Immune Response Pulse with tumor Ags or gene transferPulse with tumor Ags or gene transfer

Cl II Cl I

Autologous bone marrow (treated Autologous bone marrow (treated in vitro in vitro with Ab + C’) transplantation following with Ab + C’) transplantation following irradiation/chemotherapy.irradiation/chemotherapy.

Allogeneic bone marrow transplantation Allogeneic bone marrow transplantation (matched for HLA Ag) – Graft versus (matched for HLA Ag) – Graft versus host reactionhost reaction

Cytokine TherapyCytokine Therapy

Inject cytokines.Inject cytokines.

1.1. Interleukin -2 (IL-2) high dose - Alone Interleukin -2 (IL-2) high dose - Alone or or with cellswith cells

Melanoma and renal cell carcinomaMelanoma and renal cell carcinoma

Activates NK and CTLActivates NK and CTL

Toxic - fever, edema, shockToxic - fever, edema, shock

2.2. Tumor necrosis factor (TNF-Tumor necrosis factor (TNF-) - ) - CarcinomaCarcinoma

3.3. Interferon (IFN)-Interferon (IFN)- Activates NK activityActivates NK activity

Hairy B cell leukemia, renal cell carcinoma, Hairy B cell leukemia, renal cell carcinoma, melanoma, Kaposi sarcoma, hematologic melanoma, Kaposi sarcoma, hematologic cancerscancers

4.4. IFN-IFN- : Increases Cl II MHC expression. : Increases Cl II MHC expression. Ovarian carcinomaOvarian carcinoma

5.5. Hematopoietic growth factors: Hematopoietic growth factors: Overcome neutropeniaOvercome neutropenia

Granulocyte-macrophage colony stimulating Granulocyte-macrophage colony stimulating factor (GM-CSF)factor (GM-CSF)

Gene therapyGene therapyIntroduce cytokine genes for IL-2, IL-4, IL-12, IFN- or GM-CSF into tumor cells.

tumorT cell

M

IL-2

GM-CSF

SUMMARYSUMMARY

Tumors should express TSTA.Tumors should express TSTA. Th cells and CTL are important in tumor Th cells and CTL are important in tumor

rejection.rejection. NK cells and macrophages also play an NK cells and macrophages also play an

important role.important role. Tumors evade immune system in a Tumors evade immune system in a

number of ways.number of ways. Immunotherapy is promising.Immunotherapy is promising.

Reading Reading Immunology By Male, Brostoff, Roth and Roitt7th EditionPages 401-419