This lesson explains how changes in cell growth can produce tumors and how the adaptive immune system can recognize and attack abnormal cells. It also examines ways that cancers evade immune defenses.
The cell cycle is the sequence of stages through which a eukaryotic cell grows and divides. Cancer develops when cells lose control of this cycle and proliferate abnormally. These cells may also lose the ability to differentiate into the type of cell normally found in their location. They can lose contact inhibition, the usual restraint that prevents cells from growing over neighboring cells, and form an abnormal mass.
All flashcards
What is contact inhibition?
The restraint that normally limits cell growth when cells contact neighboring cells.
How can tumor antigens activate adaptive immunity?
They can be presented to lymphocytes and recognized as targets, including when they were not part of self-tolerance screening.
What do T_H1 cells contribute to antitumor immunity?
They release cytokines that support natural killer-cell activity and cytotoxic T-cell responses.
How is sipuleucel-T prepared?
A patient's antigen-presenting cells are collected, cultured with a tumor-specific molecule, and returned to the patient.
How can T-VEC affect a tumor?
The injected virus can infect and lyse tumor cells and stimulate antitumor immunity.
Quiz questions
Which statement best distinguishes a tumor from cancer?Answer: A tumor is an abnormal mass that may be benign or malignant; cancer involves abnormal proliferation linked to loss of cell-cycle regulation.
Which cytokine can promote naïve helper T-cell differentiation into T_H1 cells during an antitumor response?Answer: IL-12
What is the central preparation step in sipuleucel-T therapy?Answer: The patient's antigen-presenting cells are cultured with a tumor-specific molecule and returned to the patient.
How does T-VEC act as a therapeutic cancer treatment?Answer: It is injected into tumors, where it can lyse tumor cells and stimulate antitumor immunity.
What is a potential advantage and limitation of oncolytic viruses?Answer: They may preferentially damage tumor cells, but selectivity and treatment effects are not guaranteed.
Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.