Final Exam - Tumor Immunology

Tumor immunity

immunization to a SPECIFIC tumor cell type. Must occur prophylactically in order to prevent tumor growth. ie) immunization against fibrosarcoma will only render immunity to that specific cancer type.

Primary host

a host that grows the tumor

Syngeneic host

a host that is genetically identical to the primary host which grew the tumor

tumor immunity, tumor specific

A syngeneic host injected with irradiated tumor cells from a primary host will develop _______ against that specific tumor. This suggests the existence of _______ antigens.

Type of cancer and method of induction

two factors influencing tumor immunity

UV

_____ induced cancers are highly immunogenic

Methylcholanthrene

_____induced cancers are moderately immunogenic

Spontaneous

______ tumors are poorly immunogenic

immunosuppressed

There is an increased relative risk of cancers in patients who are....

Kaposi's sarcoma and skin cancer

two cancers seen in patients having kidney transplant.

Epstein Barr virus, HPV, hepatitis B and C

four viruses that are capable of triggering the development of cancer in immunosuppressed patients

T antigen

antigen produced from SV40 and polyoma viruses which can trigger cancer development

E6 and E7

two antigens of the human papilloma viruses that cause cervical cancer.

HPV

antigens of this virus are prophylactically administer and currently tested for clinical activity in human tumors.

Spontaneous tumors

tumors which occur without a cause and are antigenically distinct.

Cross reactive immunity

interaction among tumors which is significantly weaker than individual specific antigenicity. Has considerable success in identification of individually distinct antigens

Heat shock proteins

all tumor specific antigens belong to this family of proteins. They chaperone peptide tumor antigens and present them to APCs to be processed and presented to T cells via class I or class II MHC molecules. Immune response is specific to the peptide, not the chaperone. If they dissociate, tumor rejection will not occur.

Tumor specific antigenic epitopes, antigenic fingerprint of the tumor

two components of contained in the peptides of heat shock proteins

HSP90, HSP70, HPS170, calreticulin

four families of heat shock proteins which serve as tumor specific antigens

CD40 and CD80/85

two genes that are upregulated in response to HSP molecule ligation

MCP-1 and MIP 1 alpha

two chemokines produced in response to HSP molecule ligation

MAGE, BAGE, GAGE, NY ESO1

four cancer/testes antigens that can be recognized by T cells

GP100, Trp 1, Trp 2

three differentiation antigens that are lineage specific, but not tumor specific, which are expressed on normal tissues as well as tumors and can be recognized by T cells

Melanoma

unique tumor specific antigens have been seen in this type of cancer

CD8

cells present in draining lymph nodes that become activated by tumor antigens present by APCs. After activation they enter circulation to reach the targeted tumor.

Natural killer cells

cells that play a crucial role in immune response to cancer

Concomitant immunity

phenomenon where an already growing tumor confers resistance to a second tumor of the same cancer type within a certain window of time, but this immunity fails to eliminate the tumor that elicited the response.

6-9, CD8, CD4

Concomitant tumor immunity occurs up to ____ days following tumor growth due to high levels of ____ cells. This effect ends as ____ cell levels begin to rise.

Ca 125

Marker of ovarian cancer

CD25

Marker of leukemia

CD30

Marker of Hodgkin's lymphoma

Inhibitory cytokines (TGF beta, IL 10)

Down regulation by regulatory T cells

Down regulation of MHC class I

Antigen loss

Loss of beta 2 microglobulin

five factors which can contribute to resistance to tumor recogterm-35nition

CTLA 4

receptor expressed on the surface of T cells whose over expression can raise the stimulatory threshold and/or inhibit T cell proliferation. This receptor can be inactivated by antibodies to increase anti-tumor response against highly immunogenic tumors. Even more effective when combined with a vaccine as well.

Anti-CD25 antibodies

antibodies which can be administered to tumor bearing mice to elicit a robust T cell response and protective tumor immunity even against aggressive tumor models such as B16 melanoma.

Rituximab

CD20 antibody used in the treatment of lymphoma

Trastuzumab

HER2/Neu antibody used in the treatment of breast cancer

Cetuximab

epidermal growth factor receptor antibody used in the treatment of colon cancer

HSP peptide complex

complex used in vaccination against cancer

T cells

cells used in vaccination against cancer. Shows drastic tumor shrinkage in melanoma

secondary

Tumors of the eye are usually _____ tumors, being caused by cancers that have spread from other parts of the body

Retinoblastoma

a primary tumor formed by cancer of the retina. The most common childhood eye cancer which usually presents in children under the age of five. 500-600 of cases in the US occur each year. A third of cases spread to both eyes.

Melanoma

a primary tumor formed by cancer of melanocytes. Occurs in adults 60-65. 1500-2000 of cases in the US occur each year.

Diagnosis, size, aggressiveness

three factors which affect the treatment of tumors in the eye

Laser treatment, freezing, radiation, surgical removal

four methods in the treatment of tumors in the eye.