Tumor Immunology Flashcards
(26 cards)
Who is at a higher risk for tumor occurrence or recurrence
immunosuppressed individuals
Do tumors trigger immune response?
Yes, mice immunized with Tumor A, survive transplant of tumor A but not tumor B (anamnestic)
Immune surveillance theory
mechanisms responsible for allograft rejections evolved as a means to defend against spontaneous neoplasms
Solid tumors
shown lymphocytic and monocytic infiltrates
Innate immunity is mediated by _______ and recognize
NK cells and recognize a lack of self HLA on cells (tumor cells) using KIRs
Adaptive humoral immunity in tumor cell immune response
IgG and IgM and complement may lyse tumor cells, activated phagocytes destroy tumor cells opsonized with IgG, neutralization by sterically interfering with tumor cells ability to adhere, ADCC
ADCC kills tumor cells by
IgG bindign antigenz on tumor cells, attracting K cells with Fc receptors (NK, CTL, eosinophil, Mo, neutrophil), K cell in close contact released apoptotic substances
Adaptive cell-mediated response to tumor cells
activated CD8+ (Th1 IL-2 activation) destroy tumor cells
activated macrophage response to tumor cells
release lysosoma enzymes and TNF-alpha onto tumor cell surface
lymphokine-activated natural killer cells (LAK) response to tumor cells
retrieval of cancer patient’s lymphoid cells, stimulation with IL-2 in vivo, followed by transfusion back to patient (lacks success)
Tumor infiltrating lymphocytes response to tumor cells
NK cells and T cells retreived from cancer patient’s, stimulated with IL-2 in vivo, followed by transfusion back to patient (lacks success)
CD4+ T helper cells response to tumor cells
produced cytokines (IFN-gamma and IL-2) that activate macrophages and upregulate HLA class I (tumor cells) and II (APC) and activates NK cells and CTL
Immunologically privileged sites
eye, brain, gonads, outer skin
tumors arising in Immunologically privileged sites
cells of immune system cannot access it
Tumor cells may inhibit T cell function by producing
prostaglandins and Th1 inhibiting IL-10
Anergy
a lack of reaction by the body’s defense mechanisms to foreign substances
Tumor cell production of TGF-beta
inhibit Th1 response, decrease NK cytolytic activity, inhibit antigen uptake, dampen CD4 and CD8 T cells function
Antigenic modulation
tumor cell survival due to constantly changing antigenic make-up
tumor cells may secrete antigens to
bind antibodies in circulation preventing them from binding the tumor cell
Blocking antibodies on tumor cells
prevent CTL recognition and do not lead to cell death
Tumor mass
size of tumor is inversely proportional to the ability of the immune system to destroy it
Monoclonal antibodies used to kill tumor cells
target surface antigen of cancer cell, ADCC kills cell, antibody may be conjugated to a toxic substance
Rituximab
anti-CD-20 target B cells in B cell lymphoma
Her2/neu protein
targets breast and ovarian cancer cells
