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TUMOR IMMUNOLOGY - Coggle Diagram
TUMOR IMMUNOLOGY
WHAT IS TUMOR?
Cells that escape the normal controls that govern cell division & cellular longevity among other things.
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TUMOR ANTIGENS
Antigenic substances produced in tumor cells that can trigger immune response. The distinction of TA is based on their recognition by the host immune cells. Certain TA are used as tumor markers
2 major types: Tumor Specific Antigen (TAA) (not unique to tumor cells) & Tumor Associated Antigen (TSA) (unique to tumor cells)
CATERGORIES TUMOR AG
ONCOFETAL AG
Char: Ag on malignant cells represent structures that are present on fetal/embryonic cells but disappear from normal adult cells
Ag: CEA, AFP & MAGE (present in any normal adult tissues except testes)
Disease: CEA & AFP - colon cancer (GI tract). MAGE - Melanoma & carcinoma of lung, bladder & liver
ONCOGENE
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Disease: Breast, liver, colorectal & brain cancer
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TUMOR IMMUNOLOGY
GOAL
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To utilize the immune response to tutors for the purpose of diagnosis, prophylaxis & therapy
Body's immune system can be recognise tumor cells as "non-self" & attempt to destroy & stop them from spreading
RESPONSES
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Note: some immune responses promote cancer growth. Defining the immune response against cancers - dev. of new immunotherapy
IMMUNE SURVEILLANCE
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EQUILIBRIUM PHASE: elimination phase is not successful, tumor cells undergo mutation that aid their survival (immunoediiting)
ESCAPE PHASE:tumor cells have acquired the ability to evade immune system & grow unimpeded become clinically detectable
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If the tumor cells are not completely eliminated, variants occur that eventually escape the immune system & proliferate to form a tumor
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EFFECTOR MECHANISMS
Abs & B cells - complement mediated lysis, opsonisation
Destruction of tumor cells by T lymphocytes (CMR) - CTL produced IFN-γ & TNF-a (antitumor responses cytokines). cd4+ Th cells - induction, regulation & maintenance of such CTLs (cytolysis & apoptosis)
ADCC (CMR) - binding of tumor-specific Abs to the surface of the tumor cells. Involve the interaction of various cells (granulocytes & macrophages) which possess surface receptors for the Fc portion of the antibody attached to the tumor cells. The destruction of the tumor cells by substances release from these cells that carry Fc portion receptor of Abs (cytolysis & phagocytosis)
Destruction of Tumor by NK cells - Lyse MHC I -ve tumor & virus infected cells. Have receptors for FC region of IgG & can participate in ADCC. Secretes TNF-⍺ that induces haemorrhage & tumor necrosis (cytolysis, apoptosis)
Cytokines - effector mechanisms may be stimulated or inhibited depending on cytokines produced. TNF-a & IFN-γ have antitumor effects