8) Interferons ______. A) are virus-specific, so that an interferon produced against one virus could not protect cells against another virus B) act by increasing the rate of cell division C) interfere with viral replication within cells D) are routinely used in nasal sprays for the common cold 9) Regulatory or suppressor T cells ______. A) release cytokines that increase the activity of cytotoxic T cells and activated B cells B) decrease their activity as antigenic stimulus decreases C) may function in preventing autoimmune reactions D) aid B cells in antibody production 10) Activated T cells and macrophages release ______ to mobilize immune cells and attract other leukocytes into the area. A) Cytokines B) Perforins C) Interleukin 1 proteins D) Interleukin 2 proteins 11) Which of the following is a part of the second line of defense against microorganisms? A) keratin B) cilia C) gastric juice D) phagocytes 12) Complement proteins and antibodies coat a microorganism and provide binding sites, enabling macrophages and neutrophils to phagocytize the organism. This phenomenon is termed ______. A) diapedesis B) agglutination C) opsonization D) chemotaxis 13) Which of the following is not characteristic of the adaptive immune system? A) It is antigen-specific. B) It is dependant on T and B lymphocytes. C) It has memory. D) It is present from birth. 14) Cytotoxic T cells ______. A) are the only T cells that can directly attack and kill other cells B) require the double recognition signal of I MHC plus II MHC on the target cell in order to function C) function mainly to stimulate the proliferation of other T cell populations D) self-destruct once the antigen has been neutralized
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9) Regulatory or suppressor cells release cytokines that: The correct answer is B) decrease their activity. Show more…
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Coaching Activity: Protecting Against Infectious Diseases and Sexually Transmitted Infections macrophages suppressor T cells humoral immunity killer T cells virus antibodies helper T cells vaccinations 1. When an antigen such as a [box] enters the body, the body reacts by producing [box] that are matched to the particular antigen in order to destroy or weaken it. This process is a component of an intricate system called [box]. In cell-mediated immunity, specific white blood cells ([box] and lymphocytes) are the key players. Two forms of lymphocytes are involved in the immune response: B cells and T cells. The T cells work in few different ways; [box] activate B cells to produce antibodies. In addition, they activate other T cells and macrophages. In contrast, [box] attack malignant or infected cells, and [box] turn off or restrain the activity of B cells, killer T cells, and macrophages. Finally, memory T and B cells are created. These cells will recognize the virus if it appears again, and the specific immune response will be able to respond quickly and efficiently. Weakened forms of the virus are found in [box], which are introduced to the body in order to stimulate the specific immune response and create antibodies, memory B cells, and memory T cells. In this way, the virus will not be able to infect the body in the future.
Suman K.
Immune Response Model The immune system is powerful because of its specificity (cells attack specific invaders) and its memory (cells are ready to launch a rapid attack if the same type of invader returns again). When a foreign cell enters the human body, the intruder begins to multiply and diffuse through the bloodstream. Each foreign cell has its own specific antigens. An antigen is a large molecule with a distinct configuration that triggers an immune response. Helper T cells, a specific type of white blood cells, roam around the human body, looking for foreign antigens. Once a helper T cell recognizes a foreign antigen, it activates B cells, another type of white blood cells, that begin to proliferate rapidly. The proliferation of white blood cells is activated when helper T cells come into contact with antigens. Foreign cells multiply rapidly. The strength of the immune response reflects the fraction of antigens that are detected by helper T cells. As the number of antigens grows, more antigens are detected, and the white blood cells proliferate more rapidly. Increasing proliferation is the source of the positive loop that drives the growth of the white blood cells. A negative loop comes into play as the white blood cells perform their duty and destroy foreign cells. As the number of white blood cells grows exponentially, antibodies or killer T cells are produced, and the number of foreign cells is drastically reduced. The immune response senses the absence of foreign cells. Helper T cells come into contact with fewer and fewer antigens, and white blood cell proliferation drops off, leaving the body with a good number of white blood cells ready to fend off a second possible invasion.
Shaiju T.
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