Failure of Immune Response Against Tumor
An effective tumor response to tumor can be hampered by the following
factors:(if effector cells exist and tumors are antigenic,why arenít tumors rejected?)
a. Site of tumor. Some tumors arise in areas not accessible to effector cells (eye and central nervous system).
b. Antigenic modulation. Tumor cells may undergo several antigenic changes.
c. Blocking factors. Immune complexes and cytophilic antibodies can mask surface tumor antigens or prevent binding by effector cells or lytic antibodies.