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TUMOR IMMUNOLOGY. Jan Żeromski 2011/2012. EVIDENCE FOR ANTI-TUMOR IMMUNOLOGICAL REACTIVITY. Lymphoid cell infiltrates and proliferative reaction in regional lymph nodes correlate with favourable prognosis in some tumors,
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TUMOR IMMUNOLOGY Jan Żeromski 2011/2012
EVIDENCE FOR ANTI-TUMOR IMMUNOLOGICAL REACTIVITY • Lymphoid cell infiltrates and proliferative reaction in regional lymph nodes correlate with favourable prognosis in some tumors, • Transplants of experimental tumors are rejected in animals previously exposed to the same tumor,
EVIDENCE FOR ANTI-TUMOR IMMUNOLOGICAL REACTIVITY-2 • This resistance may be transfered to another animal by means of lymphocytes of animal previously harboring or exposed to this tumor, • Individuals with immunodeficiencies show higher frequencies of some tumor types
IMMUNOLOGICAL SURVEILLANCE • Definitionprevention of development of the majority of tumors by early destruction of atypic cells by the immune system of the host. • Evidencespontaneous regression of cancer, higher incidence of tumors in early childhood and in elderly people, autopsy findings.
TUMOR ANTIGENS • Tumor specific antigens (TSA) : expressed only on tumor cells and not on normal ones • Tumor associated antigens (TAA)- may be expressed in variable amounts also on normal cells
TUMOR ANTIGENS-2 In terms of origin the following TAA are distinguished: • Ag of spontaneous tumors of unknown etiology • Ag of tumors induced by oncogenic viruses • Ag carcino-embryonic (oncofetal ones) • Ag of tumors induced by chemicals and/or radiation
VIRUSES AND HUMAN TUMORS • Primary liver cancer: HBV, HCV • Cervical cancer: HPV 16, 18 and other • Burkitt lymphoma and other lymphomas: EBV • Nasopharyngeal carcinoma: EBV: HTLV-1 • Adult T cell leukaemia: (HTLV-1) • Kaposi sarcoma: herpes virus-8 (KSHV)
ONCO-FETAL ANTIGENS • Features: not expressed in healthy people in postnatal life but may abundant in fetal period. They are encoded in geno • Their expression is the result of derepression of particular gene.
ONCO-FETAL ANTIGENS-2 • Carcinoembryonic antigen(CEA): cell membrane glycoprotein (200 kDa) of many human cancers • -fetoprotein (fetal albumin) major fetal serum protein. Present in cells of primary hepatic carcinoma and in malignant germinal teratomas • PSA – prostate specific antigen
IMMUNOLOGICAL FACTORS OF ANTI-TUMOR RESPONSE • Antibodies • Cytotoxic T lymphocytes - CTL (CD8+) • Cytokines with cytotoxic properties (TNF-alfa, LT) • Immunoregulatory cytokines (IFN-gamma, IL-2, IL-12, IL-18) • NK cells, NKT cells, gamma/delta T cells • Macrophages, granulocytes - ADCC
TUMOR ESCAPE MECHANISMS • Tumor’s progression and growth are faster than the generation of the immune response („sneaking through” mechanism) • Tumor and its microenvironment inactivate most of the host defense mechanisms
MALIGNANT PLEURAL EFFUSIONS SURFACE EXPRESSION OF Fas AND FasL ON TUMOR CELLS
IMMUNOTHERAPY OF CANCER
TUMOR IMMUNOTHERAPY- POSSIBILITIES • Monoclonal antibodies • Sensitized T (CD8+) cells • LAK cells (lymphokine activated killers) • Cytokines or their genes (IL-2, IL-12, IFN-alfa etc.)
TUMOR IMMUNOTHERAPY- POSSIBILITIES -2 • NK cells • Co-stimulatory molecules or their genes inserted into tumor cells • Dendritic cells loaded with tumor peptides • Nonspecific immunotherapy (BCG)
Monoclonal Antibodies used in Cancer Therapy • Campath 1H [CD52] - CLL • Rituximab [CD20] - as above • Epratuzumab [CD22] - as above • IDEC-152 [CD23] - as above • Cetuximab [EGFR] - colon, HNC • MDX-447 [EGFR i CD64] - as above • Gefitinib [EGFR-TK] - prostate, lung cancer • Herceptin [EGFR] - mammary cancer
Tumor microenvironment.Evaluation of fine needle aspiration biopsy by means of DNA microarray