Study sets, textbooks, questions
Upgrade to remove ads
Block 4 Exam
Terms in this set (40)
Influenza pandemics are often driven by antigenic __________, while antigenic __________ is the reason why flu vaccines must be given yearly.
In the case of HIV infection by sexual transmission, a key step in the establishment of disseminated HIV infection is the replication of the virus in the regional lymph nodes draining the mucosal site of initial virus entry. The ability of the virus to spread from the mucosa to the regional lymph node is made possible by:
The virus' ability to infect migratory cells that carry it from the mucosa to the lymph node.
In the late 1990s, a group of individuals was discovered that remained uninfected with HIV, in spite of multiple exposures to the virus. Analysis indicated that these HIV-resistant individuals had a homozygous deficiency caused by a 32-bp deletion in a single gene, and furthermore, that this mutation was present at a frequency of ~10% (in heterozygous form) in individuals of European descent. These data provided clear evidence indicating that:
HIV infection requires a co-receptor in addition to CD4.
In 1918, a worldwide epidemic of influenza A resulted in the deaths of 40-50 million people. This strain of influenza A, known as H1N1—referring to the genotypes of the viral surface proteins, hemagglutinin (H) and neuraminidase (N)—was shown to be derived from an avian virus that adapted to infect and grow in human cells. Interestingly, by 1957, the H1N1 strains of Influenza A had completely disappeared from the human population, to be replaced by new strains (H2N2) that contained three gene segments from avian origin. The most likely explanation for the disappearance of the early twentieth century form of H1N1 Influenza A virus is:
High levels of existing immunity in the human population to the H1N1 surface antigens
Most immunological subversion techniques are entirely unique to bacteria and viruses.
One important feature of retroviruses such as HIV is their generation of a provirus, a copy of the viral genome that is inserted into the host cell chromosome. In addition to providing a template for viral mRNA transcription, the proviral genome:
Is maintained long-term and transmitted to all of the cell's progeny
A common and potent strategy used by many bacteria is __________ which is possible through several pathways. One option is to block cytokine receptors on immune cells and another is the production of analogs of cytokines
suppression of inflammation (???)
A distinct indicator of AIDS is the collapse of CD4 T cell levels. Why is this clinical indicator useful?
CD4 T cells are the main site of HIV replication
HIV is often the direct cause of death in a person it infects.
Studies have shown that secondary lymphoid tissues are a major reservoir of HIV in infected individuals. In part, this is due to the high numbers of viral target cells expressing CD4, such as T cells, macrophages, and dendritic cells. Surprisingly, secondary lymphoid tissues were also found to contain large numbers of infectious virus particles in the form of immune complexes. A comparison of the viral species found in these immune complexes indicates that they include virus particles that have been retained for over a year. The cells responsible for this reservoir of infectious HIV are:
Follicular dendritic cells
Which of the following features renders HIV nearly impossible to eliminate from a host once infected?
(???) Rapid antigenic drift
To avoid detection and elimination by host immune systems, each strain of Streptococcus pneumonia possesses a unique capsular polysaccharide form that results in antibodies being able to bind to the parasite, allowing S. pneumoniae to generate infection even when the host has been previously exposed. Which type of immunological subversion is this?
(???) Antigenic variation
Why is it good to use a combination or rotation of drugs while treating HIV infection?
to prevent the evolution of drug resistance
__________ and basophils are critical in restoring tissues to homestasis following allergic reactions
Allergic responses to inhaled antigens occur when an individual is first sensitized to the antigen (i.e., the allergen), inducing an immune response, and then has a subsequent exposure to the same antigen. The sensitization phase is characterized by:
Induction of a CD4 T cell type II immune response
A new form of treatment for chronic allergies, omalizumab, prevents binding immunoglobulin binding and cross-linking using monoclonal antibodies that bind the Fc-region of the target antibody. To prevent allergic reactions, which immunoglobulin subtype must omalizumab target?
__________ cells are largely to blame for many allergic symptoms
Mast cell actions are generally driven by a suite of cytokines unique to allergic reactions.
Allergic reactions are triggered once allergens trigger IgE cross links with high-affinity IgE receptors on natural killer cells.
Cellular hypersensitivity reactions are mediated by antigen-specific effector
Anaphylaxis is the result of a widespread release of histamine among other mediators of allergic reactions in the blood stream. Which cell type is responsible for mediating this reaction?
Connective tissue mast cells
The normal allergic response is dominated by __________. Allergic desensitization is a method used to restore one's tolerance to an antigen. In successful cases of allergic desensitization, the allergic reaction becomes skewed to produce __________.
IgE --> IgG
Type I hypersensitivity reactions represent immediate-type allergic reactions mediated by __________ antibodies, with mast cell-activation being the major final effector mechanism.
Which of the following statements supports the hygiene hypothesis?
Reduced occurrence of asthma in those with a high exposure to microorganisms during early childhood.
Most treatments for allergies are generally to treat symptoms rather than the root cause.
Delayed-type hypersensitivity reactions take several hours to days to be enacted because:
Th1 cells specific to the antigen are initially rare in circulation
The prevention of inflammatory immune responses to inhaled antigens in healthy individuals has mechanisms in common with those that prevent inflammatory immune responses to commensal microbes in the gut. One important component of immune regulation shared by these two situations is:
The important role for CD4 regulatory T cells in suppressing inflammatory immune responses in these tissues
__________ is a chronic disease characterized by inflammation of the synovium (the thin lining of a joint). As disease progresses, the inflamed synovium invades and damages the cartilage; this invasion is followed by bone erosion.
Rheumatoid arthritis (RA)
Sites such as the brain, eye, testes, and uterus are "immunologically privileged", where tissue grafts often last indefinitely. Which of the following is not one of the reasons why this privilege occurs?
Increased presence of TNF-a at privileged sites regulates the immune response
Systemic lupus erythematosis (SLE) is an autoimmune disease characterized by the development of autoantibodies specific for DNA and other nuclear antigens. Patients with SLE show a wide variety of symptoms that include anemia, skin rashes, joint and muscle pain, heart problems, and kidney damage. This is considered a systemic autoimmune disease because:
The autoantigen targeted by the immune system is not tissue specific
Which of the following components of the immune system are involved in an autoimmune disease such as lupus or multiple sclerosis?
All are involved
The majority of monogenic defects in humans that cause autoimmune diseases are in genes that regulate T cell responses. These include the AIRE, FOXP3, and FAS genes. These findings indicate that B cells and innate immune cells are not important in autoimmunity.
Relatively common autoimmune diseases include type 1 diabetes, psoriasis, IBD, and multiple sclerosis. The main destructive agent in these diseases are __________, who recognize self peptides or peptides derived from the commensial microbiota that are complexed with self MHC molecules.
Autoreactive cells that escape tolerance-inducing mechanisms can still be regulated so that they do not cause disease. This regulation takes two forms: the first is _____1_____ and is mediated by regulatory T cells and antigen-presenting cells; the second is _____2_____ and has its basis in limits on the size and duration of immune responses that are programmed into lymphocytes themselves.
1. extrinsic; 2. intrinsic
Mutations in which cytokine receptors are significantly related to autoimmune disease?
(???) IL-12 and IL-23
Autoimmune diseases can be transferred from mother to offspring during pregnancy.
Tolerance due to regulatory lymphocytes is distinguished from other forms of self-tolerance by the fact that ___________ cells have the potential to suppress self-reactive lymphocytes that recognize antigens differently.
The response to nonself antigens on transplanted organs is called
Which of the following is not an autoimmune disease?
Autoimmune diseases are more common in women than men.
Recommended textbook explanations
Biocalculus: Calculus for the Life Sciences
Lisa A. Urry, Michael L. Cain, Peter V Minorsky, Steven A. Wasserman
Lehninger Principles of Biochemistry
David L Nelson, Michael M. Cox
Principles of Life
David E. Sadava, David M. Hillis, H. Craig Heller
Sets with similar terms
clinical microbiology lecture 17
Immunopathology Path 3-16 Exam 1
Ch. 16 Disorders in Immunity
Other sets by this creator
Immunology Block 4 Exam
Immunology Module 4 Quiz
Immunology Block 1 Exam
Other Quizlet sets
AP Psych Test 1
Chapter 6 Study Thingy SS
ÉCONOMIE, théories et ouvrages
11/13 What did we learn this week?