Chapter 8: T cell mediated immunity

The triggering of CD40 on the B cell serves as a costimulatory signal (second signal) for _____________.

B cell activation

One of the most potent costimulatory signals received by T cells is delivered by binding of a surface protein called _______ on the surface __________ to the _______ receptor on T cells.

B7, Antigen presenting cells

Naive CD8 T cells are more dependent upon costimulation than _________. They must get a high level of costimulation from APC or help from _________.

CD4 T cells, TH1 cells

Activated ______ T cells give rise to either ____, _____, ______, ______ or _______.

CD4 positive, TH1, TH17, TH2, TFH or Treg T cells

________ Positive T cells give rise to cytotoxic T cells which are restricted to MHC 1 and kill virally infected and transformed cells.

CD8

_____________ can be stimulated by antigen in the absence of co-stimulatory signals. This is necessary since almost any cell can be infected by virus.

Effector T cells

____________ Down regulate dendritic cells and other T cells to regulate T cell responses.

Treg T cells

T cells selectively home to particular secondary lymphoid tissues by specific interactions between ____________ on their surface and on the HEV L-selectin makes the first contact, then chemokines enhance the affinity of the LFA-1 integrin that bind the cell adhesion molecules on the HEV tightly.

cell adhesion molecules

Effector T cells express four times the amount of ___________ and this helps them stabilize contact with cells that do not express the co-stimulatory molecules such as _______.

cell adhesion molecules, B7

TH1 cells can also recruit macrophages to the site of infection by increasing macrophage production and ________ from the blood vessels into the infected tissue

chemotaxis

Effector T cells secrete several different ________, some of which act on the same cells that produce them _______ and others that act on other nearby cells ___________.

cytokines, autocrine, paracrine

CD8 T cells are __________ which act by killing infected cells. CD4 T cells include TH1 and TH2 T cells. TH1 T cells promote ___________ by activating macrophages and stimulating the production of opsoninizing antibodies. TH2 T cells promote ______________ by stimulating B cell proliferation and differentiation.

cytotoxic T cells, cell mediate immunity, humoral immunity

Antigen usually enters secondary lymphoid tissue associated with antigen presenting cells such as _____________ that migrate from the site of infection of damage.

dendritic cells

Effector T cells express a different integrin than naive cells so theta they are able to ____________ into sites of infection or inflammation rather than enter __________.

exit blood vessels, secondary lymphoid tissues

Cytokines such as interferon gamma are not prepackaged like the _________ in cytotoxic T cells so they must be made after contact with the ___________.

granules, macrophages

If activated macrophages fail to get rid of the infectious agent it will be walled off by a __________, which consists of infected cells surrounded by giant cells called _________ and T cells.

granuloma, epithelioid cells

Mature naive T cells circulate in the blood and enter secondary lymphoid tissues through specialized blood vessels called ____________.

high endothelial venues (HEV)

Cytotoxic T cells ________ to which they specifically bind by two processes. First _______ contain perforin and granulysin which within the T cell move to the site of contact with the target cell. Second, _______ which are serene proteases enter the cell and cleave proteins which initiates ________. Cytotoxic T cells also kill by means of expressing Fas ligand on their surface with binds to the receptor, Fas on target cells and can stimulate __________.

kill target cells, granules, granzymes, apoptosis, apoptosis

List the three types of antigen presenting cells.

macrophages, dendritic cells and B cells

TH1 cells cause _______ to become more efficient at killing internalized microorganisms. They do this by releasing _________ which stimulates their lysosomes to become more efficient at fusing the phagosomes and increased production of killing substances within the lysosomes such as enzymes, nitrous oxide and reactive oxygen containing compounds.

macrophages, interferon gamma (a cytokine)

Upon activation, T cells produce increased amounts of _______ and switch from expressing a _______ affinity receptor for _______ to expressing ________ affinity _________ receptor,

IL-2, low, high, IL-2

_______ is a cytokine- soluble proteins that are secreted by WBCs and cat on rather than distance from the source. This cytokine plays an important role in _____________________.

IL-2, regulating T cell proliferation

TH2 cells releases the cytokines, ______ and ______ which also stimulate the B cell (but not other B cells) to proliferate, differentiate and undergo _______________

IL-4 and IL-5, isotype switching

When TFH cells interact with such as B cell they interact through their ________ as well as a surface protein __________ which binds to ______ on the B cell.

T cell receptor, CD40 ligand, CD40

In order to become activated the lymphocytes must receive the full set of signals. This applies to all _______ as well as _______. For _______ receiving these additional signals are called __________.

T cells, B cells, T cell activation, costimulation

The interaction of T cell receptors for antigen (TCRs) with antigen plus MHC on APC leads to clustering of the ______ and the ________ causing formation of an immunological synapse.

TCR and CD4 coreceptor

_____________ Stay in the lymphoid tissue and activate B cells to produce antibody.

TFH T cells

______ promotes _______, IL-12 promotes TH1 and IL-4 promotes _______.

TGF-beta, Treg,TH2

___________ function to promote cell mediated immunity by activating macrophages and enhancing the production of antibodies that promote phagocytosis by osponization.

TH1 cells

_______ responses suppress _____ responses and vice versa.

TH1, TH2

_______ and ______ cells can be distinguished on the basis of which cytokines they secrete. Cytokines act by binding to receptors and many of these stimulate changes in gene expression through the _______ pathway. __________ are the proteins involved in directly killing infected target cells.

TH1, TH2, JAK-STAT, cytotoxins

_________ Activate neutrophils to help kill extracellular bacteria.

TH17 cells

__________ promote humoral immunity by helping to activate B cells to produce antibody

TH2 cells

The formation of the immunological synapse consists of an inner portion of closeting subsequently leads to __________ of certain sequences containing tyrosine's on the cytoplasmic tails of the CD3 proteins called ____________________. Other signaling molecules become activated in turn, including the tyrosine kinase _______ and the activation of common second messengers such as ______________ and ________________.

phosphorlyation, immunoreceptor tyrosine-based activation motifs (ITAMs), Zap 70, phospholipase gamma, GTP binding proteins such as RAS

Sensitization or activation of T cells by antigen occurs in the _________________.

secondary lymphoid tissue

B cells can only present antigen to T cells that are ___________ that is part of the same antigen for which they are specific. These are called ___________ interactions.

specific for a peptide, cognate

T cells that are not stimulated, will leave the lymphoid tissue in response to a chemical gradient of ___________ which is produced in greater amounts in the medulla of lymph nodes and outside of the lymph node.

sphingosine 1-phosphate (SIP)

If the source of antigen is in the blood, this will happen in the _________. If it is from peripheral tissues it will happen in the _____________. If it is from the respiratory tract or gut it will happen in tissues such as_____________________________.

spleen lymph nodes tonsils, bronchial associated lymphoid tissue, Peyers' patches, appendix

B cells only take up and process antigen that is bound by specific antibody on their ________.

surface