DNA vaccine induces TH1 response.

CpG

plasmid

APC

TLR9 IL12 TH1

CTL

IgG2a

B cell

DNA vaccine is preferred for inducing immunity against intracellular infection.

pXL2 (RSV DNA vaccine): TH1 responsepXL0 (control)

Live RSV vaccine: balanced TH1/TH2

Formalin inactivated RSV: TH2 response

DNA vaccine expressing multiple antigens

DNA vaccine priming / boosting with other vaccines

Mucosal vaccine

Mucosal surface is the major site of pathogen entry.

Mucosal vaccine induces both mucosal and systemic immunity.Injected vaccines are poor inducers of mucosal immunity.

DC

M

B

GCT T

Plasma cells, memory B cells TH cells, CTL

Mucosal lymphocytes home to mucosal tissues.

Peyer’s patch

Plasma cells, CTL, TH cellsMemory cells

Lymph node

Blood circulation Blood circulation

Other mucosal tissuesOther mucosal tissues

Inductive site

Effector siteEffector site

Common mucosal immune system

Lymphocyte homing to mucosal tissueMucosal tissue-specific adhesion molecules and chemokine/chemokine receptors

plasma cells

CCR10 CCL28

Epithelial cellsof intestine andother mucosal tissues

47 integrin

Endothelial cells of venules in intestine

MADCAM1 (addressin)

CCR9 CCL25

Epithelial cellsof intestine andother mucosal tissues

47 integrin

Endothelial cells of venules in intestine

MADCAM1 (addressin)

Effector T cells

Mucosal induction site

Mucosal effector site

Mucosal immunization also induces systemic immunity.

DC

M

B

GCT T

Mucosal lymphoid tissue

Lymph node

Systemic immunity

Mucosal immunity

Mucosal plasma cells produce IgA.

Epithelial cells

Mucus Dimeric IgA Neutralization

IgA+

Mucosal plasma cells IgG

Systemic immunity(lymph nodes, spleen)

Blood circulation

Blood circulationMucosal effectorT and B cells

CTL

TH

IgA > IgG

IgG > IgA

Preferential localization of mucosal immunityto induction site

Challenges in mucosal vaccine

Degradation, dilution on mucosal surface

Live attenuated pathogen (polio vaccine, S. typhi vaccine)

Use as recombinant vectors vaccines

Prevent tolerance

Mucosal adjuvant to induce “danger signal” (activate DCs)

Mutated enterotoxins of bacteria (e.g. cholera toxin)

PAMPs (e.g. CpG, flagellin)

Immune response against tumor

Tumor cells Tumor Ag

Uptake of Tumor AgBy immature DCs

Mature DCsMHC I and II-antigen

B7

CD4 T

CD8T

CTL

CTL

Kill tumor cells

Lymph node

Cancer vaccine

Boosting Immune response against tumor

Tumor cellsTumor Ag

Uptake of Tumor AgBy immature DCs

Mature DCsMHC I and II-antigen

B7

CD4 T

CD8T

CTL

CTL

Kill tumor cells

Lymph node

Immunization with Tumor Ag

Loading DCs with Tumor Ag (DC vaccine)

In vitro activation of anti-tumor T cellsAdoptive transfer

Cytokine stimulation

Dendritic cell vaccine

patient

monocytes

Immature DCs

CD34+ HSCDirect isolation

Mature DCs

Cytokines

DC loaded with tumor Ag

Peptides or proteins (tumor Ag)

Tumor cell lysate

cytokinescytokines

Cancer vaccine trials

Peptide vaccines alone or with IL-12 or GM-CSF

Recombinant virus expressing tumor antigens

Irradiated autologous tumor cells or tumor cell lysates

Dendritic cells loaded with peptides, proteins, or tumor lysates, etc.

Immunosuppression mechanisms of tumor

HSC

Inhibition of DC maturation

CMP iMC

Immature Myeloid cells

myeloid DCs

M

granulocyte

Immature DC

activation

Mature DCBone marrow

Peripheral tissues

Immature DCs capture antigens.

Mature DCs activate T cells.

Immature DC Mature DC

MHC II-

B7-

MHC I+ MHC I+

MHC II+

B7+ Antigen capture Antigen presentation

CD4 T

CD8 T

TH

CTL

2o lymphoid tissues

T cell toleranceT cell activation

Tumors inhibit DC maturation.

Immature DC Mature DC

MHC II-

B7-

MHC I+MHC I+

MHC II+

B7+

Tumor cells

VEGF

M-CSF IL6

Cyclooxygenase-2 (COX2) produces prostaglandin E2, PGE2)

VEGF (vascular endothelial growth factor)

M-CSF (macrophage colony-stimulating factor)

PGE2

IL10

TGF-

gangliosides

Tumor microenvironment

Reduced number of DCs in cancer patientsClinical Cancer Research 6, 1755-1766 (2000)

HNSCC: head and neck cancer

Defective DC function in cancer patients

DCs (mismatched class II MHC) CD4 T cells Proliferation (3H incorporation)

Cancer patients have higher proportions of Immature DCs.

Immature DCs: HLA-DR- (class II MHC)

B7-

CD40-

Surgery removal of tumor reduces immature DCs.

5 patients

Proportion of immature DCs

Reduction of immature DCs after chemotherapy and Anti-VEGF antibody treatment.

Tumors induce the expression of B7-H1, H4 in APCs.

Normal maturation

B7.1(CD80), B7.2(CD86)

T cell activation

B7-H1, H4

Tumor microenvironment

B7-H1, B7-H4 inhibit T cell activation (co-inhibitory molecules)

Some tumor cells express B7-H1,B7-H4.

B7-H1,B7-H4

CD4+CD25+FoxP3+ T cells (5-10% of peripheral CD4 T cells)

Cancer patients have higher levels of Treg cells.

Inhibit T cell response.

Depletion of CD25+ cells increases tumor rejection.

Depletion of Treg cells by DAB389IL-2 (denileukin diftitox, ONTAK)

High affinity IL2 receptor

IL2R: CD25

Low affinity IL2 receptor

Naive T cellEffector T cellCD4+CD25+Treg

CD25+ T cell

IL2Diphtheria toxin

DAB389IL-2

CD25- T cell

DAB389IL-2 preferentially kill CD25+ T cells.

DAB preferentially kills CD25high Treg cells.

CD4+CD25neg

CD4+CD25int

CD4+CD25highCD4+CD25neg T cells: naïve resting T cells

CD4+CD25int T cells: activated T cells

CD4+CD25high T cells: Treg cells (FoxP3+)

J. Clinical Investigation 115, 3623-3633 (2005)

RCC: Renal cell carcinoma

Donor: healthy control

Cancer patients have highly levels of CD25+Treg cells(FoxP3+)

Depletion of CD25+Treg cells enhances T cell response against tumor.

patient Vaccinated with DC vaccineagainst RCC

Determine the frequency of CD8+ T cellsthat express IFN- in response to tumor.

Patient Treat with DAB

Treatment with CTLA4-specific antibodyCD4+CD25+Treg cells constitutively express CTLA4.

CTLA4 antibodies improve tumor rejection, but cause autoimmunity.

Adoptive transfer of anti-tumor T cellsScience 298, 850-854 (2002)

13 Cancer Patients

(metastatic melanoma)

Melanoma

Tumor cells

TIL(tumor infiltrating

Lymphocyte)

Expansion of TIL in cell culture

Anti-CD3+IL2

These T cells can be activatedBy tumor antigens in self-MHC

Lymphodepleted patients

Cyclophosphamidefludarabine

Infusion of anti-tumor T cell with IL2

6/13 responded5/13 have autoimmune melanocyte destruction

Tumor regression after a few month

Relevant part in book

Cancer vaccine and therapy: page 511-520