Gamma delta T bunky

1. gamma delta T bunky Pokroky v imunologii Listopad 2005 Karel Drbal

2. Invariantn� lymfocyty (lidsk�) Cells MHC Ligands Receptors NK T CD1d a-Gal/Cer Va14(24)/Vb8(11) Non a-Gal/Cer Va3.2,Va8/Vb8 Tissue gd CD1c, MICA lipids Vg2/Vd1 Blood gd ? Prenyl pyrophosphates, Vg9/Vd2 phosphorylated nucleotides MAIT cells MR1 peptides? Va19(7.2)/Ja33 CD8aa IEL TL CD8aa ? B1 B cells - TI-antigens (PC) IgM MZ B cells - TI-antigens (broad) IgM NK cells MHC class I Variable KIR, Ly49,  CD94-NKG2D/DAP12 Fetal liver-derived hV?9Vd2 cells express T-cell receptors (TCRs) with canonical junctions, whereas adult peripheral blood lymphocyte (PBL)-derived V?9Vd2 cells express junctionally diverse TCR with conserved specificity for phosphoantigens. Not listed are human Vd1 T cells, a prominent subset in the intestinal epithelium, which has been associated with recognition of various antigens, including CD1c and MHC class I (MIC). This is because of the apparent absence of canonical sequence motifs and the naive phenotype of most Vd1 T cells. Similarly, ?d T cells specific for the non-classical T10 and T22 MIC molecules are not listed because of the lack of recurrent junctional motifs within the few reactive TCRs analysed so far.Fetal liver-derived hV?9Vd2 cells express T-cell receptors (TCRs) with canonical junctions, whereas adult peripheral blood lymphocyte (PBL)-derived V?9Vd2 cells express junctionally diverse TCR with conserved specificity for phosphoantigens. Not listed are human Vd1 T cells, a prominent subset in the intestinal epithelium, which has been associated with recognition of various antigens, including CD1c and MHC class I (MIC). This is because of the apparent absence of canonical sequence motifs and the naive phenotype of most Vd1 T cells. Similarly, ?d T cells specific for the non-classical T10 and T22 MIC molecules are not listed because of the lack of recurrent junctional motifs within the few reactive TCRs analysed so far.

3. Expression of an unique, conserved T cell receptor (TCR) Specialized anatomical distribution Characteristic cell phenotypes A distinct pathway of developmental maturation Unique antigen specificities A broad spectrum of cell-cell interactions A unique capacity to protect the host against specific pathogens A nonredundant capacity to regulate the course and consequences of immune responses Uniquely age-dependent activities�an hypothesis. Fast response Obecn� vlastnosti gd T bunek

4. Preskupen� TCR lokusu postupne: TCRD->TCRG->TCRB->TCRA zac�n� Dd2-Dd3->Dd2-Jd1->Vd-Jd1 (vyskytuje se t� u jin�ch lymfocytu: B a NK bunek)

5. Preskupen� TCR lokusu

6. gd TCR nomenklaturapotvrzeno HUGO Gene Nomenclature Committee dostupn� na: http://imgt.cines.fr clovek (funkcn� jen 2 variabiln� TRGV regiony Vg2, Vg9)

7. gd TCR nomenklaturapotvrzeno HUGO Gene Nomenclature Committee dostupn� na: http://imgt.cines.fr clovek (funkcn� jen 2 variabiln� TRDV regiony Vd1-Vg2, Vd2- Vg9)

8. gd TCR nomenklatura my� (u�itecn� srovn�n� pro star�� citace), nov� terminologie t� dostupn� na:http://imgt.cines.fr

9. V�voj diverzity invariantn�ho gd TCR behem ontogeneze omezen� v�ber variabiln�ch segmentu TCR zvy�uj�c� se CDR3 variabilita behem ontogeneze (v�ce u Vd1)  fet�ln� strevo Vd1 Vd2 Fetal liver-derived hV?9Vd2 cells express T-cell receptors (TCRs) with canonical junctions, whereas adult peripheral blood lymphocyte (PBL)-derived V?9Vd2 cells express junctionally diverse TCR with conserved specificity for phosphoantigens. Not listed are human Vd1 T cells, a prominent subset in the intestinal epithelium, which has been associated with recognition of various antigens, including CD1c and MHC class I (MIC). This is because of the apparent absence of canonical sequence motifs and the naive phenotype of most Vd1 T cells. Similarly, ?d T cells specific for the non-classical T10 and T22 MIC molecules are not listed because of the lack of recurrent junctional motifs within the few reactive TCRs analysed so far. Fetal liver-derived hV?9Vd2 cells express T-cell receptors (TCRs) with canonical junctions, whereas adult peripheral blood lymphocyte (PBL)-derived V?9Vd2 cells express junctionally diverse TCR with conserved specificity for phosphoantigens. Not listed are human Vd1 T cells, a prominent subset in the intestinal epithelium, which has been associated with recognition of various antigens, including CD1c and MHC class I (MIC). This is because of the apparent absence of canonical sequence motifs and the naive phenotype of most Vd1 T cells. Similarly, ?d T cells specific for the non-classical T10 and T22 MIC molecules are not listed because of the lack of recurrent junctional motifs within the few reactive TCRs analysed so far.

10. CDR oblasti ab vs.gd TCR CDR1, 2 MHC specifita Ag specifita diverzita: invariabiln� variabiln�vazba: MHC ligand CDR3 Ag specifita diverzita: variabiln� invariabiln� vazba: peptid MHC (TL) somatick� hypermutace Ig t� zvy�uje variabilitu hlavne u CDR1 a 2somatick� hypermutace Ig t� zvy�uje variabilitu hlavne u CDR1 a 2

11. Unik�tn� lokalizace gd T bunek druhove unik�tn� - clovek < hlodavci < pre�v�kavci, pt�ci residentn� v tk�n�ch - pomer ab:gd - 1:50 (periferie, uzliny) vs. 1:5 (strevo) prvn� obrann� linie - ? cetnost v periferii (muk�zn� povrchy, ku�e) omezen� migrace - pr�mo do tk�n� souvislost s Ag-specifitou: nemus� prob�rat vz�cn� Ag v LN jako to delaj� konvencn� ab T bunkysouvislost s Ag-specifitou: nemus� prob�rat vz�cn� Ag v LN jako to delaj� konvencn� ab T bunky

12. My�� v�vojov� linie � tk�nove specifick� ontogeneze ve vln�ch intrathymov� klasick� v�voj:fet�ln� ku�e: (Vg5Vd1) DETC -pouze u my�i, muk�za: (Vg6)- monospecifick� (invariantn�) TCR dospel� lymfoidn� org�ny: (Vg1, Vg4, Vg2, Vg7)-vysok� diverzita TCR extrathymov� v�voj (dospel�): strevo (Vg7, Vg1) CD8aa (IEL) gd T bunky -vysok� diverzita TCRpl�ce, epitelie: -n�zk� diverzita nebo monospecifick� (invariantn�) TCR ~ Vg5Vd1 DETC ? odpoved na stres (heat-shock, transformace, infekce) DETC = dendritic epidermal T cells IEL=intrapithelial lymphocytes Figure 7.21. The rearrangement of T-cell receptor ? and d genes in the mouse proceeds in waves of cells expressing different V? and Vd gene segments. At about 2 weeks of gestation, the C?1 locus is expressed with its closest V gene (V?5; also known as V?3). After a few days V?5-bearing cells decline (upper panel) and are replaced by cells expressing the next most proximal gene, V?6. Both these rearranged ? chains are expressed with the same rearranged d-chain gene, as shown in the lower panels, and there is little junctional diversity in either the V? or the Vd chain. As a consequence, most of the ?:d T cells produced in each of these early waves have the same specificity, although the antigen recognized in each case is not known. The V?5-bearing cells become established selectively in the epidermis, whereas the V?6-bearing cells become established in the epithelium of the reproductive tract. After birth, the a:� T-cell lineage becomes dominant and, although ?:d T cells are still produced, they are a much more heterogeneous population, bearing receptors with a great deal of junctional diversity. DETC = dendritic epidermal T cells IEL=intrapithelial lymphocytes Figure 7.21. The rearrangement of T-cell receptor ? and d genes in the mouse proceeds in waves of cells expressing different V? and Vd gene segments. At about 2 weeks of gestation, the C?1 locus is expressed with its closest V gene (V?5; also known as V?3). After a few days V?5-bearing cells decline (upper panel) and are replaced by cells expressing the next most proximal gene, V?6. Both these rearranged ? chains are expressed with the same rearranged d-chain gene, as shown in the lower panels, and there is little junctional diversity in either the V? or the Vd chain. As a consequence, most of the ?:d T cells produced in each of these early waves have the same specificity, although the antigen recognized in each case is not known. The V?5-bearing cells become established selectively in the epidermis, whereas the V?6-bearing cells become established in the epithelium of the reproductive tract. After birth, the a:� T-cell lineage becomes dominant and, although ?:d T cells are still produced, they are a much more heterogeneous population, bearing receptors with a great deal of junctional diversity.

13. Lidsk� v�vojov� linie - ontogeneze Vd1 (tk�ne) -vysok� diverzita TCR Vd2Vg9 (hlavne krev, cirkulace) -omezen� diverzita TCR -nejcasnej�� maturovan� populace lymfocytu behem ontogeneze (do 1 roku) odpoved na stres (heat-shock, transformace, infekce) We also find distinct differences between the V1 and V2 subpopulations of T cells. Although both V1 and V2 cells display signs of early activation in neonates, V2 cells in particular are activated very early, with the majority of V2 cells showing evidence of prior activation in individuals before 1 year. This represents the earliest immunological maturation of any lymphocyte compartment in humans and most likely reflects the importance of these cells in controlling pathology due to common environmental challenges. We also find distinct differences between the V1 and V2 subpopulations of T cells. Although both V1 and V2 cells display signs of early activation in neonates, V2 cells in particular are activated very early, with the majority of V2 cells showing evidence of prior activation in individuals before 1 year. This represents the earliest immunological maturation of any lymphocyte compartment in humans and most likely reflects the importance of these cells in controlling pathology due to common environmental challenges.

14. Vd1 a Vd2 ontogeneze Vg9 p�rov�n� s Vd1 a Vd2 fenotyp Vd1 a Vd2

15. Vd2 subsety IL-2, IFNg & perforin - produkce maturovan�mi gdT bunkami

16. Vd2 subsety � obdobn� jako u ab T bunek naive (Vd2 TN): CD62L+ CD27+ CD45RA+ CD16- central memory (Vd2 TCM): CD62L+ CD27+ CD45RA- CD16- effector memory (Vd2 TEMh): CD62L- CD27- CD45RA- CD16- term. diff. eff. memory (Vd2 TEMRA): CD62L- CD27- CD45RA+ CD16+ ADCC = antibody dependent cellular cytotoxicity = Ab opsonized target cell (tumor) BrHPP = phospholigandADCC = antibody dependent cellular cytotoxicity = Ab opsonized target cell (tumor) BrHPP = phospholigand

17. Thymus Thymov� lalok

18. Thymov� v�voj Fig. 1. Stage-specific interactions associated with the T-cell development in the thymus. The thymus is a structurally complex primary lymphoid organ composed of stromal cells and immigrant hemopoietic cells, which can be broadly divided into two main anatomical regions, the outer cortex and the inner medulla. Hemopoietic stem cells enter the thymus via blood vessels at the corticomedullary junction, and under the influence of stromal cell components, undergo a series of phenotypically and functionally characterized developmental stages. Through the early stages of T-cell development within the cortex, the developing thymocytes lose the ability to give rise to various non-T-cell lineages and gradually become committed to the T-cell lineage. Following successful MHC: TCR interactions between developing thymocytes and resident stromal tissues, the developing thymocytes are selected to undergo final maturation, which occurs within the thymic medulla prior to export to the peripheral T-cell pool as fully functional self-tolerant T cells. Fig. 1. Stage-specific interactions associated with the T-cell development in the thymus. The thymus is a structurally complex primary lymphoid organ composed of stromal cells and immigrant hemopoietic cells, which can be broadly divided into two main anatomical regions, the outer cortex and the inner medulla. Hemopoietic stem cells enter the thymus via blood vessels at the corticomedullary junction, and under the influence of stromal cell components, undergo a series of phenotypically and functionally characterized developmental stages. Through the early stages of T-cell development within the cortex, the developing thymocytes lose the ability to give rise to various non-T-cell lineages and gradually become committed to the T-cell lineage. Following successful MHC: TCR interactions between developing thymocytes and resident stromal tissues, the developing thymocytes are selected to undergo final maturation, which occurs within the thymic medulla prior to export to the peripheral T-cell pool as fully functional self-tolerant T cells.

19. Thymov� v�voj Figure 1 | Thymus structure and function. The thymus is broadly divided into two histologically defined regions, the cortex and the medulla, each of which contains several different thymic epithelial cell (TEC) subtypes. In adults, T-cell precursors enter the thymus at the cortico�medullary junction, and then begin a highly ordered differentiation programme, which is linked to migration through the thymic stroma. Different thymocyte subsets are therefore found in spatially restricted regions of the thymus. The thymic cortex has been separated into four regions by Lind and colleagues8: region 1, the cortico�medullary junction, is the site of entry into the thymus and contains uncommitted progenitors, CD4�CD8� double-negative 1 (DN1) cells; in region 2, cells differentiate to the DN2 stage, undergo a proliferative clonal expansion, and lose B- and natural killer (NK)-cell potential; T-cell lineage commitment and the onset of T-cell receptor (TCR) �-chain rearrangement occurs in DN3 cells in region 3; and the transition from DN to CD4+CD8+ double-positive (DP) status occurs in region 4. DP cells then migrate back through the cortex and, having differentiated into either CD4+ or CD8+ single-positive (SP) cells, into the medulla. Positive selection occurs mainly in the cortex, and requires cortical TECs, whereas negative selection occurs mainly in the medulla, and is mediated by medullary TECs and thymic dendritic cells (DCs). SP cells that have completed the differentiation programme egress from the medulla to the periphery. CEC, cortical epithelial cell; MEC, medullary epithelial cell. Figure 1 | Thymus structure and function. The thymus is broadly divided into two histologically defined regions, the cortex and the medulla, each of which contains several different thymic epithelial cell (TEC) subtypes. In adults, T-cell precursors enter the thymus at the cortico�medullary junction, and then begin a highly ordered differentiation programme, which is linked to migration through the thymic stroma. Different thymocyte subsets are therefore found in spatially restricted regions of the thymus. The thymic cortex has been separated into four regions by Lind and colleagues8: region 1, the cortico�medullary junction, is the site of entry into the thymus and contains uncommitted progenitors, CD4�CD8� double-negative 1 (DN1) cells; in region 2, cells differentiate to the DN2 stage, undergo a proliferative clonal expansion, and lose B- and natural killer (NK)-cell potential; T-cell lineage commitment and the onset of T-cell receptor (TCR) �-chain rearrangement occurs in DN3 cells in region 3; and the transition from DN to CD4+CD8+ double-positive (DP) status occurs in region 4. DP cells then migrate back through the cortex and, having differentiated into either CD4+ or CD8+ single-positive (SP) cells, into the medulla. Positive selection occurs mainly in the cortex, and requires cortical TECs, whereas negative selection occurs mainly in the medulla, and is mediated by medullary TECs and thymic dendritic cells (DCs). SP cells that have completed the differentiation programme egress from the medulla to the periphery. CEC, cortical epithelial cell; MEC, medullary epithelial cell.

20. Thymov� v�voj CTECkortik�ln� thymick� epiteli�ln� bunky MTEC - AIRE medul�rn� thymick� epiteli�ln� bunky Figure 1 | Overall scheme of T-cell development in the thymus. Committed lymphoid progenitors arise in the bone marrow and migrate to the thymus. Early committed T cells lack expression of T-cell receptor (TCR), CD4 and CD8, and are termed double-negative (DN; no CD4 or CD8) thymocytes. DN thymocytes can be further subdivided into four stages of differentiation (DN1, CD44+CD25-; DN2, CD44+CD25+; DN3, CD44-CD25+; and DN4, CD44-CD25-)41. As cells progress through the DN2 to DN4 stages, they express the pre- TCR, which is composed of the non-rearranging pre-Ta chain and a rearranged TCR �-chain43. Successful pre-TCR expression leads to substantial cell proliferation during the DN4 to double positive (DP) transition and replacement of the pre-TCR a-chain with a newly rearranged TCR a-chain, which yields a complete a� TCR. The a�-TCR+CD4+CD8+ (DP) thymocytes then interact with cortical epithelial cells that express a high density of MHC class I and class II molecules associated with self-peptides. The fate of the DP thymocytes depends on signalling that is mediated by interaction of the TCR with these self-peptide�MHC ligands6,51. Too little signalling results in delayed apoptosis (death by neglect). Too much signalling can promote acute apoptosis (negative selection); this is most common in the medulla on encounter with strongly activating self-ligands on haematopoietic cells, particularly dendritic cells123. The appropriate, intermediate level of TCR signalling initiates effective maturation (positive selection). Thymocytes that express TCRs that bind selfpeptide� MHC-class-I complexes become CD8+ T cells, whereas those that express TCRs that bind self-peptide�MHC-class-II ligands become CD4+ T cells; these cells are then ready for export from the medulla to peripheral lymphoid sites. SP, single positive Figure 1 | Overall scheme of T-cell development in the thymus. Committed lymphoid progenitors arise in the bone marrow and migrate to the thymus. Early committed T cells lack expression of T-cell receptor (TCR), CD4 and CD8, and are termed double-negative (DN; no CD4 or CD8) thymocytes. DN thymocytes can be further subdivided into four stages of differentiation (DN1, CD44+CD25-; DN2, CD44+CD25+; DN3, CD44-CD25+; and DN4, CD44-CD25-)41. As cells progress through the DN2 to DN4 stages, they express the pre- TCR, which is composed of the non-rearranging pre-Ta chain and a rearranged TCR �-chain43. Successful pre-TCR expression leads to substantial cell proliferation during the DN4 to double positive (DP) transition and replacement of the pre-TCR a-chain with a newly rearranged TCR a-chain, which yields a complete a� TCR. The a�-TCR+CD4+CD8+ (DP) thymocytes then interact with cortical epithelial cells that express a high density of MHC class I and class II molecules associated with self-peptides. The fate of the DP thymocytes depends on signalling that is mediated by interaction of the TCR with these self-peptide�MHC ligands6,51. Too little signalling results in delayed apoptosis (death by neglect). Too much signalling can promote acute apoptosis (negative selection); this is most common in the medulla on encounter with strongly activating self-ligands on haematopoietic cells, particularly dendritic cells123. The appropriate, intermediate level of TCR signalling initiates effective maturation (positive selection). Thymocytes that express TCRs that bind selfpeptide� MHC-class-I complexes become CD8+ T cells, whereas those that express TCRs that bind self-peptide�MHC-class-II ligands become CD4+ T cells; these cells are then ready for export from the medulla to peripheral lymphoid sites. SP, single positive

21. V�vojov� stadia * ISP in mouse express CD8, but in human express CD4

22. gd T vs. ab T-lineage commitment most probable competitive model: delta, gamma, beta simultaneous rearrangement � which is productive dictates cell fate (but no direct evidence for this) Figure 1. TCR Signal Strength and the a� versus ?d T Cell Fate Decision Early thymocyte precursors (CD4-CD8-, double negative, or DN) rearrange their TCR �, ?, and d genes and, depending on the outcome of rearrangement, may express either a ?dTCR (top) or a pre-TCR composed of � TCR and an invariant preTa chain (middle). Expression of a ?dTCR leads to a strong TCR signal, high levels of ERK phosphorylation, strong induction of the Egr family of transcription factors, and ultimately promotes the ?d T cell fate. Expression of the pre-TCR leads to a weaker TCR signal, moderate phosphorylation of ERK and Egr induction, and ultimately promotes the a� T cell fate. Experimental manipulations that reduce ?dTCR signaling in the thymus (bottom, indicated by an �x�) promote the a� fate at the expense of ?d development. Figure 7. Signal Strength Model for a�/?d Lineage Choice Immature DN thymocytes have the potential to become either an a� or a ?d lineage cell, depending on the strength of the TCR signal. The surface level of the TCR (pre- or ?dTCR) on immature DN thy- mocytes determines its signal strength. Typically, the pre-TCR is expressed at low levels on immature DN thymocytes, whereas surface expression of the ?dTCR is relatively high. Therefore, if a cell expresses the pre-TCR, then it will receive a �weak� signal, choose the a� lineage fate, undergo a strong proliferative burst and transi- tion to the DP stage. However, if a cell expresses high levels of the ?dTCR, then it will receive a �strong� signal, choose the ?d lineage fate and remain DN. Conversely, if it expresses low levels of the ?dTCR, then it will receive a �weak� signal and choose the a� lin- eage fate. Because the choice to become an a� lineage cell by a ?dTCR+ DN thymocyte occurs infrequently in wild-type mice, it is denoted by a dotted line. most probable competitive model: delta, gamma, beta simultaneous rearrangement � which is productive dictates cell fate (but no direct evidence for this) Figure 1. TCR Signal Strength and the a� versus ?d T Cell Fate Decision Early thymocyte precursors (CD4-CD8-, double negative, or DN) rearrange their TCR �, ?, and d genes and, depending on the outcome of rearrangement, may express either a ?dTCR (top) or a pre-TCR composed of � TCR and an invariant preTa chain (middle). Expression of a ?dTCR leads to a strong TCR signal, high levels of ERK phosphorylation, strong induction of the Egr family of transcription factors, and ultimately promotes the ?d T cell fate. Expression of the pre-TCR leads to a weaker TCR signal, moderate phosphorylation of ERK and Egr induction, and ultimately promotes the a� T cell fate. Experimental manipulations that reduce ?dTCR signaling in the thymus (bottom, indicated by an �x�) promote the a� fate at the expense of ?d development. Figure 7. Signal Strength Model for a�/?d Lineage Choice Immature DN thymocytes have the potential to become either an a� or a ?d lineage cell, depending on the strength of the TCR signal. The surface level of the TCR (pre- or ?dTCR) on immature DN thy- mocytes determines its signal strength. Typically, the pre-TCR is expressed at low levels on immature DN thymocytes, whereas surface expression of the ?dTCR is relatively high. Therefore, if a cell expresses the pre-TCR, then it will receive a �weak� signal, choose the a� lineage fate, undergo a strong proliferative burst and transi- tion to the DP stage. However, if a cell expresses high levels of the ?dTCR, then it will receive a �strong� signal, choose the ?d lineage fate and remain DN. Conversely, if it expresses low levels of the ?dTCR, then it will receive a �weak� signal and choose the a� lin- eage fate. Because the choice to become an a� lineage cell by a ?dTCR+ DN thymocyte occurs infrequently in wild-type mice, it is denoted by a dotted line.

23. T- bunecn� sign�ln� dr�hy Figure 1. TCR Signal Strength and the a� versus ?d T Cell Fate Decision Early thymocyte precursors (CD4-CD8-, double negative, or DN) rearrange their TCR �, ?, and d genes and, depending on the outcome of rearrangement, may express either a ?dTCR (top) or a pre-TCR composed of � TCR and an invariant preTa chain (middle). Expression of a ?dTCR leads to a strong TCR signal, high levels of ERK phosphorylation, strong induction of the Egr family of transcription factors, and ultimately promotes the ?d T cell fate. Expression of the pre-TCR leads to a weaker TCR signal, moderate phosphorylation of ERK and Egr induction, and ultimately promotes the a� T cell fate. Experimental manipulations that reduce ?dTCR signaling in the thymus (bottom, indicated by an �x�) promote the a� fate at the expense of ?d development. Figure 7. Signal Strength Model for a�/?d Lineage Choice Immature DN thymocytes have the potential to become either an a� or a ?d lineage cell, depending on the strength of the TCR signal. The surface level of the TCR (pre- or ?dTCR) on immature DN thy- mocytes determines its signal strength. Typically, the pre-TCR is expressed at low levels on immature DN thymocytes, whereas surface expression of the ?dTCR is relatively high. Therefore, if a cell expresses the pre-TCR, then it will receive a �weak� signal, choose the a� lineage fate, undergo a strong proliferative burst and transi- tion to the DP stage. However, if a cell expresses high levels of the ?dTCR, then it will receive a �strong� signal, choose the ?d lineage fate and remain DN. Conversely, if it expresses low levels of the ?dTCR, then it will receive a �weak� signal and choose the a� lin- eage fate. Because the choice to become an a� lineage cell by a ?dTCR+ DN thymocyte occurs infrequently in wild-type mice, it is denoted by a dotted line. Figure 1. TCR Signal Strength and the a� versus ?d T Cell Fate Decision Early thymocyte precursors (CD4-CD8-, double negative, or DN) rearrange their TCR �, ?, and d genes and, depending on the outcome of rearrangement, may express either a ?dTCR (top) or a pre-TCR composed of � TCR and an invariant preTa chain (middle). Expression of a ?dTCR leads to a strong TCR signal, high levels of ERK phosphorylation, strong induction of the Egr family of transcription factors, and ultimately promotes the ?d T cell fate. Expression of the pre-TCR leads to a weaker TCR signal, moderate phosphorylation of ERK and Egr induction, and ultimately promotes the a� T cell fate. Experimental manipulations that reduce ?dTCR signaling in the thymus (bottom, indicated by an �x�) promote the a� fate at the expense of ?d development. Figure 7. Signal Strength Model for a�/?d Lineage Choice Immature DN thymocytes have the potential to become either an a� or a ?d lineage cell, depending on the strength of the TCR signal. The surface level of the TCR (pre- or ?dTCR) on immature DN thy- mocytes determines its signal strength. Typically, the pre-TCR is expressed at low levels on immature DN thymocytes, whereas surface expression of the ?dTCR is relatively high. Therefore, if a cell expresses the pre-TCR, then it will receive a �weak� signal, choose the a� lineage fate, undergo a strong proliferative burst and transi- tion to the DP stage. However, if a cell expresses high levels of the ?dTCR, then it will receive a �strong� signal, choose the ?d lineage fate and remain DN. Conversely, if it expresses low levels of the ?dTCR, then it will receive a �weak� signal and choose the a� lin- eage fate. Because the choice to become an a� lineage cell by a ?dTCR+ DN thymocyte occurs infrequently in wild-type mice, it is denoted by a dotted line.

24. Interakce T bunek a thymov�ho epitelu Dal�� ligandy/receptory -> sign�ln� dr�hy -> TF zodpovedn� za �lineage commitment� T bunek a v�voj thymov�ho epitelu: Delta, Jagged / Notch Wnt / Frizzled -> b-catenin -> TCF, LEF FGF / FGFR -> Ras, MAPK -> Jun, Fos, STATs, Gli TGFb, activins, BMPs / TGFR -> Smads Sonic hedgehog / Patched, Smoothened ->Gli (vet�inou morfogenetick� proteiny/dr�hy) Figure 1. TCR Signal Strength and the a� versus ?d T Cell Fate Decision Early thymocyte precursors (CD4-CD8-, double negative, or DN) rearrange their TCR �, ?, and d genes and, depending on the outcome of rearrangement, may express either a ?dTCR (top) or a pre-TCR composed of � TCR and an invariant preTa chain (middle). Expression of a ?dTCR leads to a strong TCR signal, high levels of ERK phosphorylation, strong induction of the Egr family of transcription factors, and ultimately promotes the ?d T cell fate. Expression of the pre-TCR leads to a weaker TCR signal, moderate phosphorylation of ERK and Egr induction, and ultimately promotes the a� T cell fate. Experimental manipulations that reduce ?dTCR signaling in the thymus (bottom, indicated by an �x�) promote the a� fate at the expense of ?d development. Figure 7. Signal Strength Model for a�/?d Lineage Choice Immature DN thymocytes have the potential to become either an a� or a ?d lineage cell, depending on the strength of the TCR signal. The surface level of the TCR (pre- or ?dTCR) on immature DN thy- mocytes determines its signal strength. Typically, the pre-TCR is expressed at low levels on immature DN thymocytes, whereas surface expression of the ?dTCR is relatively high. Therefore, if a cell expresses the pre-TCR, then it will receive a �weak� signal, choose the a� lineage fate, undergo a strong proliferative burst and transi- tion to the DP stage. However, if a cell expresses high levels of the ?dTCR, then it will receive a �strong� signal, choose the ?d lineage fate and remain DN. Conversely, if it expresses low levels of the ?dTCR, then it will receive a �weak� signal and choose the a� lin- eage fate. Because the choice to become an a� lineage cell by a ?dTCR+ DN thymocyte occurs infrequently in wild-type mice, it is denoted by a dotted line. Figure 1. TCR Signal Strength and the a� versus ?d T Cell Fate Decision Early thymocyte precursors (CD4-CD8-, double negative, or DN) rearrange their TCR �, ?, and d genes and, depending on the outcome of rearrangement, may express either a ?dTCR (top) or a pre-TCR composed of � TCR and an invariant preTa chain (middle). Expression of a ?dTCR leads to a strong TCR signal, high levels of ERK phosphorylation, strong induction of the Egr family of transcription factors, and ultimately promotes the ?d T cell fate. Expression of the pre-TCR leads to a weaker TCR signal, moderate phosphorylation of ERK and Egr induction, and ultimately promotes the a� T cell fate. Experimental manipulations that reduce ?dTCR signaling in the thymus (bottom, indicated by an �x�) promote the a� fate at the expense of ?d development. Figure 7. Signal Strength Model for a�/?d Lineage Choice Immature DN thymocytes have the potential to become either an a� or a ?d lineage cell, depending on the strength of the TCR signal. The surface level of the TCR (pre- or ?dTCR) on immature DN thy- mocytes determines its signal strength. Typically, the pre-TCR is expressed at low levels on immature DN thymocytes, whereas surface expression of the ?dTCR is relatively high. Therefore, if a cell expresses the pre-TCR, then it will receive a �weak� signal, choose the a� lineage fate, undergo a strong proliferative burst and transi- tion to the DP stage. However, if a cell expresses high levels of the ?dTCR, then it will receive a �strong� signal, choose the ?d lineage fate and remain DN. Conversely, if it expresses low levels of the ?dTCR, then it will receive a �weak� signal and choose the a� lin- eage fate. Because the choice to become an a� lineage cell by a ?dTCR+ DN thymocyte occurs infrequently in wild-type mice, it is denoted by a dotted line.

25. gd TCR ligandy obecn� a konzervovan� struktury, indukovan� bunecn�m stresem ci transformac�, casto self-Ag Vd2 specifick� nepeptidov� intermedi�t biosynt�zy isoprenoidu: bakteri�ln� 1-deoxy-D-xylulose 5-phosphate (eubacteria, algae, plants, Apicomplexa) endogenn� metabolity mevalon�tov� dr�hy (eukaryotes, archaebacteria, and certain eubacteria) pyrofosfomonoestery (alkylaminy a aminobisfosfon�ty blokuj� mevalon�tovou dr�hu a t�m zpusobuj� akumulaci pyrofosfomonoesteru, napr.: IPP - izopentenyl pyrofosf�t) (napr. HMB-PP, MEP) n�dory: Apolipoprotein A-I nav�zan� na F1-ATP�zu MICA: NKG2D zprostredkovan� stimulace Vd2 (pres NK receptor, nikoliv TCR) Vd1 specifick� MHCIb bez peptidu, indukovan� stresem lidsk�: MICA, MICB (chyb� u my��): Vd1 stimulace my��: T10/T22;(jin� ne� MHCIb: MHC II, Hsp): Vg1, Vg2 stimulace lipopeptidy, kys. mykolov� (CD1a, b, c, e) hydrofobn� peptidy (N-formyl, sign�ln� peptidy) (MHC Ib)

26. gd T bunky: ochrana pred infekc� infekce virov� (CMV, HIV) a spirochetov� (Lymesk� boreli�za) -> Vd1 stimulace infekce virov� (EBV,chripka) a bakteri�ln� (Mycobacteria sp., Listeria monocytogenes, Leishmania sp., Salmonella sp.) a protozo�ln� (Plasmodium, Toxoplasma) -> Vd2 stimulace

27. gd T bunky: ochrana pred infekc�

28. gd T bunky: ochrana pred infekc� HIV

29. Imunoregulacn� funkce cytol�za (bunecn� interakce), cytokiny, chemokiny pro- / proti-z�netliv� reakce (Vg4 vs. Vg1, Vg5 DETC) : vet�inou protiz�netliv� �cinek, suprese v�voj spont�nn� dermatitidy u gdTCR KO my�iz�visl� na genetick�m pozad� a prostred� Ig class-switch, v�voj GC tissue repair (KGF) maturace DC GC = germinal center KGF = keratinocyte growth factorGC = germinal center KGF = keratinocyte growth factor

30. Imunoregulacn� funkce GC = germinal center KGF = keratinocyte growth factorGC = germinal center KGF = keratinocyte growth factor

31. gd T bunky: cytokiny Th1 i Th2 specifick� cytokiny � dle okolnost� a gd T subsetu -> (sp�e Th1) velmi rychl� odpoved tvarov�n� celkov� i specifick� imunitn� odpovedi

32. gd T bunky jako APC Vg5Vd1 DETC (my�) a Vg9Vd2 (clovek) prezentace Ag ab T bunk�m na CD1, MHCI? (cross-presentation) prezentace Ag ab T bunk�m na MHCII & kostimulace �> profesion�ln� APC

33. Journal Club Mo�nost v�beru � v�dy po 2 cl�nc�ch: funkce gdTC jako APC gd TCR struktura a vazba na TL (MHC Ib) thymov� v�voj gd TC a �lineage commitment� http://www.img.cas.cz/mi/prednasky/