Term
| Role of pathogen recognition in innate immunity |
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Definition
| responses are based on the ability of the fixed repertoire of receptors & soluble proteins of this system to recognize the structures present in many different pathogens while not in humans |
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Term
| Role of pathogen recognition in adaptive immunity |
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Definition
| based on very specific, Ag-specific level of recognition of a pathogen |
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Term
| 1st Step in Dendritic cells mediating adaptive immunity |
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Definition
| : immature iDc acquire Ags & start to differentiate into mature DC (they loose ability for phagocytosis while acquiring ability to express chemokine & other receptor & ligands enabling them to traffic to & to interact with T cells) |
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Term
| 2nd step in dendritic cells mediating adaptive immunity |
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Definition
| mature mDc transport Ags from the center of infection to the T cells zones in the secondary lymphoid tissues |
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Term
| 3rd step in dendritic cells mediating adaptive immunity |
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Definition
| the minute fraction of the naïve T cells, which have specificity of their Ag-recognition sites on the TCRs to the Ag delivered by Dcs, interact with these Ags in the context of their MHC Class I, or Class II molecules, thus becoming activated into effector TC, or TH cells, respectively. Via different set of cytokines DCs promote further differentiation of the TH cells into Th-1 & Th-2 subclasses (IFNgamma & TNF beta for Th-1 and IL-4, IL-5 & IL-13 for Th-2) |
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Term
| Promote Th1 differentiation |
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Definition
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Term
| promote Th2 differentiation |
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Definition
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Term
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Definition
| mediated via negative selection |
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Term
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Definition
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Term
| Ag recognition by T cells |
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Definition
| antigens in the context of B cells and dendritic cells (professional antigen presenting cells) recognize epitopes |
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Term
| Ag recognition by B cells |
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Definition
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Term
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Definition
| o Allelic exclusion stops the expression of RAG 1 and 2 which stops somatic recombination so that the cell if specific to one antigen |
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Term
| 2 mechanisms of diversity in variable domains of TCR and BCR |
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Definition
(1) Junctional Diversity (adding N and P nucleotides)
(2) Somatic recombination |
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Term
| Positive selection for T cells |
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Definition
| occurs in the thymus and MHC II molecules on the thymic epithelial cells select for the strongest response from the TCR. The strongest responder is moved on to a single positive cell (CD4 or CD8) |
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Term
| Positive selection for B cells |
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Definition
| occurs in the lymph nodes or other secondary lymphoid tissue. It involves somatic hypermutation and the strongest is picked to move on. The B cells are already antigen specific |
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Term
| Negative selection for T cells |
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Definition
| occurs in the thymus and the MHC class II presented by dendritic cells selects for the intermediate responder and continues onto single positive cell (CD4 or Cd8) |
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Term
| Negative selection for B cells |
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Definition
| occurs in the bone marrow and allows for clonal deletion of self-reactive cells |
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Term
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Definition
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Term
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Definition
| Ag specific and memory cells |
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Term
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Definition
| Co-stimulatory molecules in the T and B cells are used to produce signal 2 which causes Clonal expansion. Without co stimulatory activation, Clonal expansion will not occur |
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Term
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Definition
| no response to antigens, occurs if there is no co-stimulatory receptors to induce signal 2 |
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Term
| • Explain the biological significance of the IL-2/IL-2R axis in the Clonal expansion of the T cells after the priming with Ag |
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Definition
| IL-2 receptor has three chains and all three chains need to be there in order to be activated |
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