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Example Questions
Example Question #71 : Immune And Lymphatic Systems
Which of the following is not part of the innate immune response of the body?
Macrophages
Neutrophils
Digestive enzymes
Plasma cells
Plasma cells
Innate immunity can be considered the general immune response that attacks any oncoming pathogens. The skin, digestive enzymes, and phagocytic cells are all part of the innate immune response. Plasma cells are modified B-cells, and are part of the acquired immune response. They are responsible for synthesizing free antibodies in response to a specific identified pathogen.
Example Question #45 : Immune System
Type 1 diabetes is a well-understood autoimmune disease. Autoimmune diseases result from an immune system-mediated attack on one’s own body tissues. In normal development, an organ called the thymus introduces immune cells to the body’s normal proteins. This process is called negative selection, as those immune cells that recognize normal proteins are deleted. If cells evade this process, those that recognize normal proteins enter into circulation, where they can attack body tissues. The thymus is also important for activating T-cells that recognize foreign proteins.
As the figure below shows, immune cells typically originate in the bone marrow. Some immune cells, called T-cells, then go to the thymus for negative selection. Those that survive negative selection, enter into general circulation to fight infection. Other cells, called B-cells, directly enter general circulation from the bone marrow. It is a breakdown in this carefully orchestrated process that leads to autoimmune disease, such as type 1 diabetes.
The T-cells and B-cells described in the passage are both examples of lymphocytes. Lymphocytes are involved in adaptive immunity. Which of the following are characteristics of the adaptive immune system?
I. It shows a stronger reaction to a pathogen upon a second exposure, relative to the first
II. It is the first line of defense against a pathogen in the environment
III. It involves the use of macrophages and other professional phagocytes
I, II, and III
I, only
I and II
II, only
I and III
I, only
The cells of the adaptive immune system are adaptive because they change upon exposure to a pathogen, such as a virus, and mount a stronger response upon a second exposure. Initial exposure allows for the formation of memory B-cells, which will be able to react quickly to a second exposure to the antigen.
The innate immune system, comprised of non-specific cells like macrophages, is the first line of defense against environmental pathogens and does not differ between a first and second encounter with an antigen.
Example Question #72 : Immune And Lymphatic Systems
In the event of re-infection with the same pathogen, which immune cell allows for a quick response?
Natural killer cell
Helper T-cell
Plasma cell
Memory B-cell
Memory B-cell
Memory B-cells are differentiated B-cells that specifically allow for a quick response to re-infection with the same antigen. The memory B-cells proliferate after coming into contact with an antigen that they recognize, spawning plasma cells that can secrete antibodies into circulation. Helper T-cells activate immature B-cells, while natural killer cells release perforin to kill invading bacteria.
Example Question #401 : Biology
Which of the following is not part of the adaptive immune response?
B-cells
T-cells
Monocytes
Eosinophils
Monocytes
The adaptive immune system responds specifically to antigens on the bacteria, virus, or parasite surface. The adaptive immune response includes B- and T-cells, eosinophils, and basophils.
Monocytes differentiate into macrophages in response to infection or injury; they do not respond to specific antigens, and are not involved in the adaptive immune response.
Macrophages phagocytose viruses and bacteria and present their antigens to helper T-cells. Helper T-cells identify the presented antigen and activate B-cells to produce antibodies against the specific antigens. Eosinophils, basophils, additional macrophages, and killer T-cells can then respond to the antibodies to help defend against invading bacteria, viruses, and parasites.
Example Question #424 : Mcat Biological Sciences
Which of the following correctly matches the type of immunity to the way it was recieved?
Passive immunity—having the illness itself
Active immunity—antibody exchange during pregnancy
Active immunity—administering antibodies to a patient
Passive immunity—intentionally exposing yourself to infected individuals
Active immunity—vaccination
Active immunity—vaccination
Active immunity is when you are exposed to a pathogen, either through vaccination, another person with the disease, or any other means, and your body responds by producing specific antibodies with B-cells to destroy the pathogen. Passive immunity is acquired from antibody transfer, so the body does not produce its own antibodies.
Example Question #402 : Biology
In the crusade to create a vaccine for Poliomyelitis, Jonas Salk and Albert Sabin created two separate vaccines that proved to be successful in preventing Polio onset.
The Salk vaccine, which is given by standard injection, contained virus particles inactivated by an organic solvent. This method has the advantage of inactivating each of the three Polio strains with no bias.
Albert Sabin's vaccine, given by oral inoculation via sugar water, contained live virus particles that had been genetically attenuated. With this method, each of the three Polio strains acquired separate mutations that made them unable to infect the human host cells. Strain 2 in particular contained one single nucleotide polymorphism in the internal ribosomal entry site (IRES) that prevented successful viral replication.
What type of immune response does inoculation with either vaccine stimulate?
The adaptive immune response
The lymphatic immune response
Humoral immunity
The innate immune response
The adaptive immune response
The adaptive immune response is responsible for encountering antigens and creating lasting immunity against it. The humoral immune response plays a role in adaptive immunity, but is more active during the secondary exposure to an antigen.
Example Question #391 : Systems Biology And Tissue Types
Duchenne Muscular Dystrophy is an X-linked recessive genetic disorder, resulting in the loss of the dystrophin protein. In healthy muscle, dystrophin localizes to the sarcolemma and helps anchor the muscle fiber to the basal lamina. The loss of this protein results in progressive muscle weakness, and eventually death.
In the muscle fibers, the effects of the disease can be exacerbated by auto-immune interference. Weakness of the sarcolemma leads to damage and tears in the membrane. The body’s immune system recognizes the damage and attempts to repair it. However, since the damage exists as a chronic condition, leukocytes begin to present the damaged protein fragments as antigens, stimulating a targeted attack on the damaged parts of the muscle fiber. The attack causes inflammation, fibrosis, and necrosis, further weakening the muscle.
Studies have shown that despite the severe pathology of the muscle fibers, the innervation of the muscle is unaffected.
What is the best characterization of the immune response described in the passage?
Initially adaptive immunity, then innate immunity
Initially innate immunity, then adaptive immunity
Innate immunity
Auto-immunity; neither innate nor adaptive immunity describe an autoimmune reaction
Adaptive immunity
Initially innate immunity, then adaptive immunity
The initial response is an effort to repair physical damage, while the chronic response involves the recognition of antigens. Innate immunity refers to the body's natural untargeted defenses, such as the cells that would work to repair damage. Adaptive immunity is targeted to specific pathogens via antigen presentation. Thus, the pattern described in the passage is initially innate immunity, then adaptive immunity.
Example Question #426 : Mcat Biological Sciences
Inflammation is an important response of the immune system. The vasodilation of blood vessels allows for important cells of the innate immune system to move out of the blood and into the surrounding tissue. Which of the following members of the innate immune system is responsible for causing inflammation at the site of infection?
Macrophages
Mast cells
Natural Killer Cells
Dendritic cells
Mast cells
The correct answer is mast cells. Mast cells as well as granulocytes participate in the innate immune system's inflammatory response. Mast cells release histamine as well as other chemicals that allow for other cells to move from the blood stream into the tissue at the site of infection.
Example Question #403 : Biology
The HIV virus infects which of the following cells in order to diminish coordinated immune responses against pathogens?
Cytotoxic T -cells
Basophils
Macrophages
Helper T-cells
Neutrophils
Helper T-cells
The HIV virus readily attacks Helper T-cells because these cells have a signaling-cascade effect on most immune cells. Most importantly, helper T-cells stimulate B-cells to produce antibodies. As the virus destroys the helper T-cells, it effectively negates the adaptive immune system, making the body exceptionally vulnerable to infection.
Example Question #404 : Biology
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the loss of tolerance to self antigens leading to the presence of high autoantibody titers. Dysregulated peripheral tolerance and hyperactive germinal centers have been proposed to be one of the driving forces behind the accumulation of high autoantibodies.
What immune cell type is the product of germinal centers and most likely the cell mediating the production of autoantibodies?
Follicular dendritic cells
Tingible body macrophages
Follicular helper T cells
Natural killer cells
Plasma cells
Plasma cells
Plasma cells are the main product of germinal centers and are potent antibody factories. Dysregulated peripheral tolerance and germinal centers can lead to the production of plasma cells that are reactive towards self-nuclear antigens.
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