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Keywords:

  • In vivo trogocytosis;
  • T cells;
  • Viral infection

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Results and discussion
  5. Materials and methods
  6. Acknowledgements
  7. References
  8. Supporting Information

Trogocytosis describes the transfer of surface determinants between immune cells and has been implicated in immune regulation. Most findings are based on in vitro studies since in vivo trogocytosis of immune cells is difficult to detect under physiological conditions. We used low frequencies of memory P14 T cells to demonstrate that T cells perform trogocytosis in vivo if in contact with APC pulsed with GP33-peptide or expressing the antigen endogenously. Furthermore, in vivo trogocytosis of T cells is demonstrated during infections with lymphocytic choriomeningitis virus and vaccinia virus. Trogocytosis-positive T cells revealed higher expression of activation marker and cytokines, showing a more activated phenotype compared to trogocytosis-negative T cells.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Results and discussion
  5. Materials and methods
  6. Acknowledgements
  7. References
  8. Supporting Information

Transfer of surface determinants between cells of the immune system has been termed “trogocytosis” (ancient Greek trogo, for to gnaw) 1. The best-studied example for trogocytosis is the transfer of MHC molecules from APC to T cells 2, 3. Additionally, costimulatory and adhesion molecules or whole membrane patches are transferred 4–6. For T cells, initiation of trogocytosis is linked to antigen-specific TCR engagement, formation of an immunological synapse (IS) and signalling via TCR or costimulatory molecules 3, 5–9. The functional consequences of trogocytosis on T cells are a matter of debate (for review see 10). T cells acquire APC function and stimulate other T cells after trogocytosis 11–13. Furthermore, sustained T-cell activation 14, fratricide 3, 15, enhanced apoptosis 16 and induction of a Treg cell phenotype 17 after trogocytosis have been reported. Intercellular membrane transfer in vivo via trogocytosis is difficult to monitor and only addressed in few studies. In bone marrow chimeras, a permanent exchange of molecules between cells of donor and host origin occurs, probably independent of immune responses 18. Moreover, alloreactive TCR transgenic Treg cells transferred into SCID mice facilitated trogocytosis and induced suppression in vitro afterwards 19. Trogocytosis was further observed in TCR transgenic mice after transfer of antigen-pulsed DCs or after peptide immunization 16, 20 or when high numbers of pre-activated TCR transgenic T cells were transferred into peptide-immunized mice 21. In all reports non-physiological high frequencies of antigen-specific T cells were used to detect trogocytosis. Thus, the lack of reliable and less artificial experimental systems to demonstrate in vivo trogocytosis is the main obstacle to analyze the impact of this mechanism for immune regulation. We established an experimental set-up to detect trogocytosis during anti-viral immune responses. Low numbers of memory P14 T cells were transferred into C57BL/6 mice to mimic natural occurring frequencies of antigen-specific T cells. We demonstrate in vivo trogocytosis of T cells after contact with antigen-loaded APC during lymphocytic choriomeningitis virus (LCMV) and vaccinia virus infections. Furthermore, trogocytosis-positive T cells exhibit a more activated phenotype compared to trogocytosis-negative T cells. A possible explanation for this finding is that trogocytosis reflects the intensity of T cell/APC interaction. Therefore, the analysis of trogocytosis offers the possibility to identify those antigen-specific T cells within a population that were in recent contact with APC.

Results and discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Results and discussion
  5. Materials and methods
  6. Acknowledgements
  7. References
  8. Supporting Information

Detection systems for in vivo trogocytosis of CD8+ T cells

To follow trogocytosis in vivo, Thy1.1+ memory P14 T cells recognizing GP33-epitope from LCMV were transferred into C57BL/6 mice (Thy1.2+) resulting in a low frequency of antigen-specific T cells (∼1% of CD8+ T cells). One day later, splenocytes loaded with GP33-peptide or adenovirus-derived peptide (control peptide) were injected intravenously as APC. P14 T cells were detected via the Thy1.1 marker and analyzed for trogocytosis 2–3 h after APC transfer (Fig. 1A). Intercellular membrane/protein transfer from APC to T cells was quantified by three read-out systems. First, acquisition of membrane fragments from biotinylated APC by T cells. Second, the intercellular transfer of disparate MHC class I molecules from APC to T cells in a semi-allogeneic system and third, the transfer of CD45.1 molecules from APC to T cells in a CD45.1/2 mismatched system.

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Figure 1. Detection of in vivo trogocytosis by T cells. (A) Summary of experimental design. Memory P14 T cells (Thy1.1) were transferred into recipient mice (Thy1.2). One day later, 3×106 splenocytes loaded with GP33 or control peptide were injected intravenously as APC. After 3 h, P14 T cells from the spleen were analyzed for trogocytosis by gating on Thy1.1+ cells. (B) Acquisition of biotinylated membrane fragments from APC by P14 T cells was analyzed by staining with streptavidin–PE. The upper right quadrant shows percentage of trogocytosis-positive memory P14 T cells. The histogram shows an overlay of streptavidin–PE fluorescence of P14 T cells exposed to GP33-pulsed (grey) or control APC (black). The values for the mean fluorescence intensity (MFI) are indicated. (C) Detection of trogocytosis by P14 T cells in a semi-allogeneic system. 3×106 H-2bxd splenocytes were loaded with GP33 or control peptide and transferred into recipient mice (H-2b). Trogocytosis was quantified by detection of disparate H-2Dd molecules acquired by P14 T cells. Histogram shows an overlay of H-2 Dd expression of P14 T cells exposed to GP33-pulsed (grey) or control APC (black). MFI values are indicated. (D) Detection of trogocytosis by intercellular transfer of CD45.1 molecules. 3×106 CD45.1 splenocytes were loaded with GP33 or control peptide and transferred into recipients (CD45.2). In vivo trogocytosis was quantified by detection of CD45.1 molecules acquired by P14 T cells. The histogram shows an overlay of CD45.1 expression of P14 T cells exposed to GP33-pulsed (grey) or control APC (black). MFI values are indicated. (B–D) Statistical analysis of trogocytosis-positive P14 T cells exposed to control or GP33-loaded APCs is given in the right panels. (E) Antigen-specificity of trogocytosis analyzed with “cold target inhibition.” Cotransfer of biotinylated GP33-loaded splenocytes (3×106) with titrated numbers of non-biotinylated GP33 or control peptide-loaded splenocytes. Bars indicate the percentage of inhibition of trogocytosis. **p,<0.01, two-tailed Student's t-test. Representative results from 2 to 3 experiments with 2–3 mice per group are shown.

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Using biotinylated B6 splenocytes as APC, the acquisition of membrane fragments by memory P14 T cells was analyzed after staining with streptavidin–PE as a measure for trogocytosis (gating strategy for the detection of trogocytosis is shown in Supporting Information Fig. 1). Forty to seventy percent of P14 T cells acquired biotinylated membrane fragments from GP33 peptide-pulsed APC. After contact with control peptide-loaded APC (control APC) only a small fraction of P14 T cells stained positive for biotin, indicating antigen-specificity of trogocytosis (Fig. 1B). To exclude that the exchange of Thy1.1 and Thy1.2 marker molecules between T cells of donor and recipient origin interferes with the accurate detection of GP33-specific P14 T cells, which may lead to a misinterpretation of the data, we analyzed whether Thy1.1/Thy1.2 double positive T cells are detectable during trogocytosis. Only very low frequencies of CD8+ T cells (0.01%) stained double positive for the Thy1.1/Thy1.2 markers during in vivo trogocytosis, independently of whether GP33- or control peptide loaded APC were transferred (Supporting Information Fig. 2A and B). This indicates that the Thy1 marker is not transferred prevalently when T cells are in contact with each other. Furthermore, GP33-tetramer staining revealed that more than 95% of the Thy1.1 positive P14 T cells carried the antigen-specific TCR. Tetramer staining of Thy1.2 positive endogenous T cells corresponds to the low frequency of GP33-specific T cells detectable in naïve mice (Supporting Information Fig. 2C). Thus, the Thy1.1 marker is not exchanged between T cells and therefore suitable to unambiguously detect GP33-specific P14 T cells during trogocytosis in vivo. Next, we examined intercellular transfer of disparate MHC molecules from APC to T cells in a semi-allogeneic system. H-2bxd APC were loaded with GP33-peptide or control peptide (presented via H-2 Db) and acquisition of H-2 Dd molecules from APC by memory P14 T cells was analyzed (gating strategy for the detection of trogocytosis is shown in Supporting Information Fig. 1). About 50% of P14 T cells stained positive for the disparate H-2 Dd molecules when in contact with GP33-pulsed H-2bxd APC, whereas less than 10% of P14 T cells exposed to control APC were H-2 Dd-positive (Fig. 1C). Since the semi-allogeneic system is limited in long-term experiments (“allo” reactivity), we established an approach based on differences in the congenic marker CD45, which is expressed on T cells, B cells and APC. Two recent paper have demonstrated that CD45 molecules are frequently exchanged between APC and T cells during antigen-specific contact and in the context of a xenograft mouse model 22, 23. We therefore used the acquisition of CD45.1 molecules from APC by T cells to detect trogocytosis in vivo. Splenocytes from B6.SJL mice (CD45.1) were used as APC and injected into C57BL/6 mice with a low frequency of memory P14 T cells (Thy1.1, CD45.2) (gating strategy for the detection of trogocytosis is shown in Supporting Information Fig. 1). About 40% of P14 T cells stained positive for CD45.1 when in contact with GP33-pulsed APC indicating that T cells acquired CD45.1 from APC (Fig. 1D). Less than 10% of T cells were CD45.1-positive when exposed to control APC. Thus, monitoring the transfer of distinct surface molecules, like CD45.1, is sufficient to detect in vivo trogocytosis of T cells.

Antigen-specificity of trogocytosis by T cells was confirmed in a “cold target inhibition” experiment (Fig. 1E). Biotinylated GP33-loaded APC were co-injected with titrated numbers of non-biotinylated GP33-loaded or control APC and trogocytosis by T cells was analyzed. With increasing numbers of non-biotinylated GP33-loaded APC, trogocytosis of memory P14 T cells was inhibited. Co-injection of non-biotinylated control APC did not inhibit trogocytosis, demonstrating antigen specificity of the process. Taken together, we succeeded in the detection of in vivo trogocytosis using low frequencies of antigen-specific T cells. This extends initial experiments to detect trogocytosis in TCR transgenic mice that exhibited a high frequency of antigen-specific T cells 16, 20.

In vivo trogocytosis of T cells after interaction with APC expressing endogenous antigen

APC pulsed with high concentrations of peptide (10−6 M) exhibit an artificially high density of antigen-loaded MHC molecules compared to APC expressing endogenous antigens. This is a critical issue, since peptide concentration during APC pulsing directly correlates with the degree of trogocytosis by T cells 3, 6. Accordingly, in vivo trogocytosis of T cells was demonstrated so far only after loading of APC with high antigen concentrations or after immunization with high amounts of peptide 16, 20, 21. To circumvent non-physiological antigen loading of APC, we used biotinylated splenocytes from H8 transgenic mice expressing GP33-epitope endogenously. GP33 expression corresponds roughly to a pulsing with 10−8/−9 M free GP33-peptide (data not shown). Twenty to thirty percent of memory P14 T cells were trogocytosis-positive when exposed to H8 APC expressing the GP33-epitope endogenously (Fig. 2A), whereas less than 10% of the T cells showed trogocytosis after contact to control APC (gating strategy for the detection of trogocytosis is shown in Supporting Information Fig. 1). Thus, trogocytosis of T cells is detectable with endogenous expressed antigen which is an important prerequisite for the analysis during immune responses where antigen expression is more limited.

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Figure 2. In vivo trogocytosis by T cells after interaction with APC expressing endogenous antigen and phenotypical analysis of trogocytosis-positive T cells. (A) Trogocytosis of memory P14 T cells (gated on Thy1.1+ cells) recognizing endogenously expressed GP33-epitope on biotinylated H8 splenocytes. The histogram shows an overlay of streptavidin–PE fluorescence of P14 T cells exposed to H8 (grey) or control APC (black). MFI values are indicated. Pooled data from three experiments are shown (right panel). ***p<0.001, two-tailed Student's t-test. (B) Trogocytosis-positive or trogocytosis-negative memory P14 T cells were analyzed for expression of the activation marker CD69, the intracellular cytokine production and the surface expression of the degranulation marker CD107a. Overlays of expression levels of the indicated molecules are given in the histograms for trogocytosis-positive (red) and trogocytosis-negative (black) P14 T cells exposed to H8 APC and P14 T cells exposed to control APC (grey). Results shown are from one representative experiment out of three with 2–3 mice per group.

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To analyze the number of APC needed for trogocytosis, graded numbers of biotinylated H8 and B6 splenocytes were injected into C57BL/6 mice. About 60% of memory P14 T cells showed trogocytosis when exposed to 3×107 H8 APC (Supporting Information Fig. 3A). Importantly, even with a low number of 106 H8 APC antigen-specific trogocytosis of P14 T cells was detectable. Thus, trogocytosis is detectable even during immune responses when the number of APC is restricted.

Trogocytosis-positive T cells exhibited a more activated phenotype

The phenotype of trogocytosis-positive or -negative P14 T cells after exposure to APC was analyzed by staining for CD69 and CD107a and intracellular staining for IFN-γ and TNF-α (Fig. 2B) (gating strategy for the detection of trogocytosis is shown in Supporting Information Fig. 1). Trogocytosis-positive P14 T cells exhibited enhanced expression of CD69 and CD107a and increased intracellular expression of IFN-γ and TNF-α after encounter of H8 APC compared to trogocytosis-negative P14 T cells. Nevertheless, a slightly activated phenotype of trogocytosis-negative T cells could be observed after exposure to H8 APC. In contrast, P14 T cells exposed to antigen-negative APC were not activated, indicating that activation of P14 T cells was antigen-specific. The finding that trogocytosis-negative P14 T cells exposed to H8 APC were partially activated may be explained by a loss of trogocytosis marker on T cells due to membrane-turnover, by a limited sensitivity of the detection system (low level of trogocytosis marker on P14 T cells) or by a bystander activation of T cells. Furthermore, exchange of antigen between APC has been reported and therefore P14 T cells might be activated by endogenous non-biotinylated APC that had acquired GP33-peptide/MHC complexes from H8 APC. Further experiments will be needed to analyze this finding in more detail.

In vivo trogocytosis by T cells during viral infections

To investigate trogocytosis of T cells during viral infection, B6.SJL mice (CD45.1) were infected intra-footpad with LCMV and memory P14 T cells (Thy1.1, CD45.2) were transferred intravenously 3 days later. Three to four hours after T-cell transfer intercellular transfer of CD45.1 from LCMV-infected APC to P14 T cells was analyzed in draining lymph nodes and spleen (Fig. 3A) by using the gating strategy as shown in Supporting Information Fig. 1. About 30% of P14 T cells (gated on Thy1.1) stained positive for CD45.1 indicating a close contact with LCMV-infected APC and acquisition of surface molecules. In contrast, a low number of P14 T cells stained positive for CD45.1 in non-infected animals (Fig. 3B). Of note, higher frequencies of trogocytosis-positive P14 T cells were detected in local lymph nodes compared to the spleen, which reflects the high virus load in lymph nodes after the intra-footpad infection and the accessibility of LCMV-infected APC for T cells.

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Figure 3. In vivo trogocytosis by T cells in the context of viral infections. (A) Experimental set-up for the detection of in vivo trogocytosis. CD45.1 mice were infected with different isolates of LCMV or vaccinia virus and 2–3 days later transfused with memory P14 T cells (Thy1.1, CD45.2). Three to four hours later trogocytosis was analyzed in spleen and inguinal lymph nodes by detection of APC-derived CD45.1 molecules on Thy1.1-gated P14 T cells. (B) Trogocytosis by P14 T cells in spleen and lymph nodes after local infection with 104 PFU LCMV on d-3. Pooled data from three experiments are shown. (C) Trogocytosis by P14 T cells in spleen after systemic infection with 2×104 PFU WT LCMV or escape variant LCMV 8.7 (upper panel) on day-2. Additionally, trogocytosis was analyzed in mice infected with 2×106 PFU WT vaccinia virus or rVVLCMV-GP (lower panel). Pooled data from two experiments are shown. (D) Analysis of the activation status (CD69 and intracellular IFN-γ expression) of trogocytosis-positive (black squares) and -negative T cells (open squares) after contact with vaccinia virus-infected APC. Representative results from one experiment out of three with 2–3 mice per group are shown. (E) Kinetics of trogocytosis by P14 T cells during infection with rVVLCMV-GP (open squares) or VV-WT (open diamonds). Results from one out of two experiments with 2–3 mice per group are shown. **p<0.01, ***p<0.001, two-tailed Student's t-test.

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To exclude that trogocytosis of P14 T cells is a result of an overall “infectious” milieu rather than an antigen-specific interaction with APC, we infected B6.SJL mice intravenously with WT LCMV or LCMV 8.7, a virus escape variant that is not recognized by P14 T cells due to a mutation in the GP33-epitope. About 20–30% of memory P14 T cells stained positive for the CD45.1 marker after interaction with APC in WT LCMV infected mice, whereas only 3–12% of these T cells were trogocytosis-positive during infection with the LCMV 8.7 escape variant (Fig. 3C) (gating strategy for the detection of trogocytosis is shown in Supporting Information Fig. 1). Thus, under identical infectious conditions P14 T cells perform trogocytosis only after interaction with LCMV-infected cells that present the nominal antigenic peptide, demonstrating once more the antigen-specificity of in vivo trogocytosis by T cells. To study trogocytosis in a further infectious model, we analyzed T cells in the context of an infection with recombinant vaccinia virus expressing the glycoprotein of LCMV (rVVLCMV-GP). Between 25 and 50% of P14 T cells showed trogocytosis when isolated from spleens of rVVLCMV-GP-infected B6.SLJ mice, compared to only ∼10% in mice infected with WT vaccinia virus (Fig. 3C). Trogocytosis-positive P14 T cells in the absence of specific antigen (no infection or infection with virus lacking the nominal antigen) may reflect the background of our detection system or are the result of a permanent contact of T cells to APC, which facilitate the transfer of CD45.1 molecules. One may further speculate that unspecific trogocytosis of P14 T cells is a consequence of a certain self-reactivity of the high affinity transgenic P14 TCR. Next, the activation status of trogocytosis-positive and trogocytosis-negative T cells after vaccinia virus infection was analyzed. After infection with rVVLCMV-GP more trogocytosis-positive P14 T cells stained positive for CD69 and the frequency of T cells expressing IFN-γ was increased when compared to trogocytosis-negative T cells or to T cells from WT vaccinia virus infected mice (Fig. 3D). These experiments indicate that T cells acquire cell surface components from virus-infected APC in vivo in the context of LCMV and vaccinia virus infections and exhibited a more activated phenotype. The kinetic of trogocytosis by T cells was followed during infection with vaccinia virus over a period of 12 h. Increasing numbers of trogocytosis-positive P14 T cells could be detected in vivo when exposed to virus-infected APC for 4–12 h (Fig. 3E). Of note, trogocytosis-positive P14 T cells were not detectable after 8 h when H8 splenocytes were used as APC (Supporting Information Fig. 3B). This probably reflects the rapid elimination of H8 APC by P14 T cells and the loss of antigen-presenting cells or the loss of biotinylation of APC due to membrane turnover. In contrast, during viral infections where antigen persists longer due to virus replication, trogocytosis-positive P14 T cells were detectable at later time points. Further experiments are needed to analyze the dynamic of T-cell trogocytosis over the course of an infection.

Concluding remarks

We used physiological low frequencies of memory P14 T cells to detect in vivo trogocytosis which extends earlier studies where trogocytosis was observed in TCR transgenic mice 16, 20, or in lymphopenic hosts after T-cell transfer 19. In vivo trogocytosis of CD8+ T cells was analyzed by detection of intercellular transfer of biotinylated membrane compounds, disparate MHC class I molecules or CD45.1 molecules from APC to T cells. Most importantly, we demonstrate for the first time trogocytosis of T cells during immune responses in the context of viral infections. Antigen-specific T cells acquire surface molecules from LCMV or vaccinia virus infected APC in vivo. Trogocytosis-positive T cells exhibited a more activated phenotype in terms of activation markers, intracellular cytokine expression and degranulation activity when compared to trogocytosis-negative T cells, which may be explained by more intensive T cell/APC interaction. This finding will offer the possibility to identify those antigen-specific T cells within a T-cell population which were in recent contact with APC and give further information about the status of antigen-specific T cells compared to simple tetramer stainings. Taken together, these findings are the experimental basis to further study the impact of trogocytosis on the regulation of immune responses.

Materials and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Results and discussion
  5. Materials and methods
  6. Acknowledgements
  7. References
  8. Supporting Information

Mice and viruses

C57BL/6J mice were obtained from Janvier (Le Genest St-Isle, France), B6.SJL (CD45.1) mice from Taconic (Germantown, NY, USA). Thy1.1 P14 TCR-transgenic and H8-transgenic mice have been described. Mice were kept under specific pathogen-free conditions. Animal care and use was approved by the Regierungspräsidium Freiburg. LCMV strains (WE, 8.7) and vaccinia virus (WT, VVLCMV-GP) were grown on L929 or BSC-1 cells.

Flow cytometry

Anti-Thy1.1 antibody and streptavidin–APC were obtained from BD Biosciences, anti-IFN-γ, anti-TNF-α, anti-CD69, anti-CD45.1 and anti-CD107a antibodies were from eBioscience. Streptavidin–PE was obtained from BioLegend. 106 lymphocytes were stained in 50 μL of antibody working solution (4°C; 30 min). For intracellular cytokine staining T cells were surface-stained with anti-Thy1.1 and streptavidin–PE/streptavidin–APC, followed by intracellular staining with anti-IFN-γ or anti-TNF-α using the Cytofix/Cytoperm kit (BD Pharmingen). To detect CD107a, mice received 100 μL of anti-CD107a i.v. and T cells were analyzed 3 h later.

APC biotinylation

Splenocytes (2×107/mL) were washed with PBS, and biotinylated on ice for 30 min in PBS containing 1 mg/mL biotinylation reagent (EZ-Link Sulfo-NHS-LC biotin, Pierce). Biotinylated cells were washed 3× with IMDM (5% FCS, glutamine/antibiotics; complete medium). For peptide-loading, APC (2×107/mL) were incubated 1 h at 37°C in complete medium containing 10−6 M GP33 or adenovirus-derived peptide.

Trogocytosis

Memory T cells were generated by transfer of 105 naïve P14 T cells into B6 mice (Thy1.2) and subsequent infection with 200 PFU LCMV. Thirty to forty days later, 1–2×106 memory P14 T cells were isolated and retransferred into B6 mice. Trogocytosis by memory P14 T cells was analyzed by detection of intercellular transfer of surface determinants.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Results and discussion
  5. Materials and methods
  6. Acknowledgements
  7. References
  8. Supporting Information

We thank Dr. H. Pircher for comments on the manuscript. S. J. Keppler was supported by the Boehringer Ingelheim Fonds.

Conflict of interest: The authors declare no financial or commercial conflict of interest.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Results and discussion
  5. Materials and methods
  6. Acknowledgements
  7. References
  8. Supporting Information
  • 1
    Joly, E. and Hudrisier, D., What is trogocytosis and what is its purpose? Nat. Immunol. 2003. 4: 815.
  • 2
    Arnold, P. Y. and Mannie, M. D., Vesicles bearing MHC class II molecules mediate transfer of antigen from antigen-presenting cells to CD4+T cells. Eur. J. Immunol. 1999. 29: 13631373.
  • 3
    Huang, J. F., Yang, Y., Sepulveda, H., Shi, W., Hwang, I., Peterson, P. A., Jackson, M. R. et al., TCR-Mediated internalization of peptide-MHC complexes acquired by T cells. Science 1999. 286: 952954.
  • 4
    Baba, E., Takahashi, Y., Lichtenfeld, J., Tanaka, R., Yoshida, A., Sugamura, K., Yamamoto, N. and Tanaka, Y., Functional CD4 T cells after intercellular molecular transfer of 0X40 ligand. J. Immunol. 2001. 167: 875883.
  • 5
    Hwang, I., Huang, J. F., Kishimoto, H., Brunmark, A., Peterson, P. A., Jackson, M. R., Surh, C. D. et al., T cells can use either T cell receptor or CD28 receptors to absorb and internalize cell surface molecules derived from antigen-presenting cells. J. Exp. Med. 2000. 191: 11371148.
  • 6
    Hudrisier, D., Riond, J., Mazarguil, H., Gairin, J. E. and Joly, E., Cutting edge: CTLs rapidly capture membrane fragments from target cells in a TCR signaling-dependent manner. J. Immunol. 2001. 166: 36453649.
  • 7
    Patel, D. M. and Mannie, M. D., Intercellular exchange of class II major histocompatibility complex/peptide complexes is a conserved process that requires activation of T cells but is constitutive in other types of antigen presenting cell. Cell Immunol. 2001. 214: 165172.
  • 8
    Wetzel, S. A., McKeithan, T. W. and Parker, D. C., Peptide-specific intercellular transfer of MHC class II to CD4+T cells directly from the immunological synapse upon cellular dissociation. J. Immunol. 2005. 174: 8089.
  • 9
    Stinchcombe, J. C., Bossi, G., Booth, S. and Griffiths, G. M., The immunological synapse of CTL contains a secretory domain and membrane bridges. Immunity 2001. 15: 751761.
  • 10
    Davis, D. M., Intercellular transfer of cell-surface proteins is common and can affect many stages of an immune response. Nat. Rev. Immunol. 2007. 7: 238243.
  • 11
    Adamopoulou, E., Diekmann, J., Tolosa, E., Kuntz, G., Einsele, H., Rammensee, H. G. and Topp, M. S., Human CD4+T cells displaying viral epitopes elicit a functional virus-specific memory CD8+T cell response. J. Immunol. 2007. 178: 54655472.
  • 12
    Game, D. S., Rogers, N. J. and Lechler, R. I., Acquisition of HLA-DR and costimulatory molecules by T cells from allogeneic antigen presenting cells. Am. J. Transplant. 2005. 5: 16141625.
  • 13
    Xiang, J., Huang, H. and Liu, Y., A new dynamic model of CD8+T effector cell responses via CD4+T helper-antigen-presenting cells. J. Immunol. 2005. 174: 74977505.
  • 14
    Zhou, J., Tagaya, Y., Tolouei-Semnani, R., Schlom, J. and Sabzevari, H., Physiological relevance of antigen presentasome (APS), an acquired MHC/costimulatory complex, in the sustained activation of CD4+T cells in the absence of APCs. Blood 2005. 105: 32383246.
  • 15
    Cox, J. H., McMichael, A. J., Screaton, G. R. and Xu, X. N., CTLs target Th cells that acquire bystander MHC class I-peptide complex from APCs. J. Immunol. 2007. 179: 830836.
  • 16
    Mostbock, S., Catalfamo, M., Tagaya, Y., Schlom, J. and Sabzevari, H., Acquisition of antigen presentasome (APS), an MHC/costimulatory complex, is a checkpoint of memory T-cell homeostasis. Blood 2007. 109: 24882495.
  • 17
    LeMaoult, J., Caumartin, J., Daouya, M., Favier, B., Le Rond, S., Gonzalez, A. and Carosella, E. D., Immune regulation by pretenders: cell-to-cell transfers of HLA-G make effector T cells act as regulatory cells. Blood 2007. 109: 20402048.
  • 18
    Sharrow, S. O., Mathieson, B. J. and Singer, A., Cell surface appearance of unexpected host MHC determinants on thymocytes from radiation bone marrow chimeras. J. Immunol. 1981. 126: 13271335.
  • 19
    Ford McIntyre, M. S., Young, K. J., Gao, J., Joe, B. and Zhang, L., Cutting edge: in vivo trogocytosis as a mechanism of double negative regulatory T cell-mediated antigen-specific suppression. J. Immunol. 2008. 181: 22712275.
  • 20
    Riond, J., Elhmouzi, J., Hudrisier, D. and Gairin, J. E., Capture of membrane components via trogocytosis occurs in vivo during both dendritic cells and target cells encounter by CD8(+) T cells. Scand. J. Immunol. 2007. 66: 441450.
  • 21
    Tsang, J. Y., Chai, J. G. and Lechler, R., Antigen presentation by mouse CD4+T cells involving acquired MHC class II:peptide complexes: another mechanism to limit clonal expansion? Blood 2003. 101: 27042710.
  • 22
    Cho, K. S. and Hill, A. B., T cell acquisition of APC membrane can impact interpretation of adoptive transfer experiments using CD45 congenic mouse strains. J. Immunol. Methods 2008. 330: 137145.
  • 23
    Yamanaka, N., Wong, C. J., Gertsenstein, M., Casper, R. F., Nagy, A. and Rogers, I. M., Bone marrow transplantation results in human donor blood cells acquiring and displaying mouse recipient class I MHC and CD45 antigens on their surface. PLoS One 2009. 4: e8489.

Supporting Information

  1. Top of page
  2. Abstract
  3. Introduction
  4. Results and discussion
  5. Materials and methods
  6. Acknowledgements
  7. References
  8. Supporting Information

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