When is humoral immunity used

B cells with higher affinity for the stimulating antigen. B cells which can no longer bind the stimulating antigen. All of the above result from somatic hypermutation. None of the above are true.

Which of the following is NOT a similarity between the cellular and humoral immune responses? Antigen-specific lymphocytes undergo clonal selection and expansion. Cytokine signals promote effector cell differentiation. Memory cells are generated. Macrophage cytotoxicity is increased. Receptor isotype switching occurs.

B cell activation by antigen plus cytokines. In the problem below dealing with linked T and B cell immune responses to haptens, the investigators chose to look at production of IgG rather than IgM because.

IgG antibodies are easier to detect than IgM. IgG is made before IgM in an immune response. In the practice problem below dealing with linked T and B cell immune responses to haptens, IgG is not produced in experiment 4 because. HEL is not an effective carrier for PC. PC cannot be presented to B cells. T and B cell epitopes need to be identical in order for the T cells to provide help. T and B cell epitopes need to be physically linked in order for the T cell to provide help.

Different Ig isotypes are found in different body locations because they. Neutralizing antibody provides effective immunity to. Both a and b are correct. All of the above can be blocked by neutralizing antibodies.

An inactivated toxin used in a vaccine is called a n. Fc g RI on binds with highest affinity to. None of the above. Successful immune responses to bacteria which resist phagocytosis because of a polysaccharide capsule depends on the production of.

Successful immune responses to bacteria which adhere to mucosal surfaces in order to initiate infection depends on the production of. Successful immune responses to bacterial toxins depend on the production of. Fas and FasL. Mast cells release their granule contents to stimulate inflammation in response to. IgE-coated antigen binding to mast cell Fc e R. Successful immune responses to helminth parasites depends on the production of.

Haptens helped immunologists understand antigen recognition and the T cell-B cell cooperation required for IgG synthesis. In the experiment shown below, mice were injected with the small non-protein hapten phosphorylcholine, either unlinked PC or chemically linked to a protein carrier, hen egg lysozyme PC-HEL or human serum albumin PC-HSA.

IgG antibody to PC was measured after the second injection. Explain how the data shown below supports the requirement for Th and B cells to recognize epitopes on the same T-dependent antigen. Properties Of Human Antibody Isotypes. Biological half-life days. Biological Functions. Pathogen neutralization in mucosal secretions. Pathogen neutralization in tissues. Pathogen neutralization in tissues Transplacental transfer. Class ical complement activation Membrane BCR monomer. Response to Binding.

Fc g RI CD Macrophages DC Neutrophils Eosinophils. Phagocytosis Activation Respiratory burst Pathogen destruction. Macrophages Neutrophils Eosinophils Platelets Langerhans' cells. Phagocytosis Granule release eosinophils. Macrophages Neutrophils Eosinophils. Phagocytosis Inhibition of activation. B cells Mast cells. No p hagocytosis Inhibition of activation. Fc e RI. Mast cells Eosinophils Basophils. Fc a R1 CD Phagocytosis Pathogen destruction. Secondary antigen. Decker, PhD jdecker u. IgA 1.

IgA 2. Membrane BCR. Mast cell histamine release. IgG 1. IgG 2. IgG 3. IgG 4. Cell Type. Induction of NK killing. Secretion of granules. Test your knowledge and determine where to start. Combination Immunotherapies References.

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T cell-dependent activation can occur either in response to free protein antigens or to protein antigens associated with an intact pathogen. The presented antigen is then recognized by helper T cells specific to the same antigen.

The coordination between B cells and helper T cells that are specific to the same antigen is referred to as linked recognition.

Once activated by linked recognition, T H 2 cells produce and secrete cytokines that activate the B cell and cause proliferation into clonal daughter cells. After several rounds of proliferation, additional cytokines provided by the T H 2 cells stimulate the differentiation of activated B cell clones into memory B cells , which will quickly respond to subsequent exposures to the same protein epitope, and plasma cells that lose their membrane BCRs and initially secrete pentameric IgM Figure 3.

This process, called class switching or isotype switching , allows plasma cells cloned from the same activated B cell to produce a variety of antibody classes with the same epitope specificity. The variable region is not changed, so the new class of antibody retains the original epitope specificity. T cell-dependent activation of B cells plays an important role in both the primary and secondary responses associated with adaptive immunity. With the first exposure to a protein antigen, a T cell-dependent primary antibody response occurs.

The initial stage of the primary response is a lag period , or latent period , of approximately 10 days, during which no antibody can be detected in serum. The end of the lag period is characterized by a rise in IgM levels in the serum, as T H 2 cells stimulate B cell differentiation into plasma cells.

IgM levels reach their peak around 14 days after primary antigen exposure; at about this same time, T H 2 stimulates antibody class switching, and IgM levels in serum begin to decline. Meanwhile, levels of IgG increase until they reach a peak about three weeks into the primary response Figure 4. During the primary response, some of the cloned B cells are differentiated into memory B cells programmed to respond to subsequent exposures.

This secondary response occurs more quickly and forcefully than the primary response. The lag period is decreased to only a few days and the production of IgG is significantly higher than observed for the primary response Figure 4.

In addition, the antibodies produced during the secondary response are more effective and bind with higher affinity to the targeted epitopes. Plasma cells produced during secondary responses live longer than those produced during the primary response, so levels of specific antibody remain elevated for a longer period of time.

Figure 4. Compared to the primary response, the secondary antibody response occurs more quickly and produces antibody levels that are higher and more sustained. The secondary response mostly involves IgG. T-independent antigens can stimulate B cells to become activated and secrete antibodies without assistance from helper T cells.

A patient lacks the ability to make functioning T cells because of a genetic disorder. Explain your answer. Skip to main content.

Adaptive Specific Host Defenses. Search for:. B Lymphocytes and Humoral Immunity Learning Objectives Describe the production and maturation of B cells Compare the structure of B-cell receptors and T-cell receptors Compare T-dependent and T-independent activation of B cells Compare the primary and secondary antibody responses.

Think about It Compare the maturation of B cells with the maturation of T cells. Which molecule classes are T-dependent antigens and which are T-independent antigens?

Think about It What are the two signals required for T cell-independent activation of B cells? What is the function of a plasma cell?