A pharmaceutical researcher is developing a novel agent to prevent meningococcal disease in people exposed to the bacteria. Pili antigens from Neisseria meningitidis are extracted and used to generate monoclonal antibodies that impair normal pili function. The antibodies are administered to experimental animals with no prior exposure to N. meningitidis. These animals, along with control animals that had not received the antibodies, are subsequently exposed to the bacteria. Compared to the control animals, a significantly greater proportion of the animals that received the antibodies remain healthy and develop no symptoms. The efficacy of these antibodies in preventing meningococcal disease is most likely due to direct interference with which of the following microbial processes? A. Invasion of the meninges B. Adhesion to vascular endothelial cells C. Hematogenous dissemination D. Attachment to nasopharyngeal epithelial cells E. Survival inside phagocytes
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Pili are hair-like structures on the surface of bacteria that help them attach to host cells. In this case, the antibodies impair the normal function of pili. Since the antibodies are affecting the pili, they are most likely interfering with the bacteria's Show more…
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2. You are designing a vaccine to protect against infection by an invasive encapsulated bacterial species that establishes infection by living and replicating outside of the body's cells. Encapsulated means that the bacterium has a thick polysaccharide coating around the cell, making it resistant to phagocyte engulfment as well as complement-mediated lysis via the alternative pathway of complement activation. From previous research, you have learned that the most protective immune response to this type of bacteria is the production of antibodies that are specific to (and bind to) the polysaccharide molecules that form the bacterial capsule. a. What are the immune response mechanisms triggered by these protective antibodies and how do they result in clearance of the bacterial infection? b. You first decide to try vaccinating with the polysaccharide antigen along with an adjuvant, to evoke specific antibody production. This evoked a short-term immune response in adults, but did not lead to memory B cell formation. Describe the characteristics of the immune response that was elicited in this case. c. Your next strategy is to conjugate the polysaccharide molecule to a protein component, then inject with the chemically linked compound and an adjuvant. This resulted in high levels of high affinity IgG specific for the bacterial capsule polysaccharide and generated long-term memory B cells. Why was this strategy effective? Describe the key elements of the adaptive immune response that occurred upon this vaccination strategy that gave rise to immunological protection.
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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