Allogeneic Virus-Specific T Cells with HLA Alloreactivity Do Not Produce Graft-Versus-Host Disease In Human Subjects

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1252-1252
Author(s):  
J. Joseph Melenhorst ◽  
Ann M. Leen ◽  
Catherine M. Bollard ◽  
Máire F Quigley ◽  
David A Price ◽  
...  

Abstract Abstract 1252 We and others have recently established that T cell reactivity with non-self HLA (HLA alloreactivity) arises not only from naive T cells but also from the antigen-experienced T cell pool, including Epstein-Barr virus (EBV) and cytomegalovirus (CMV)-specific T cells. Virus-specific T cells could therefore mediate graft-versus-host disease (GvHD) if infused into partially HLA mismatched recipients. We reviewed our clinical experience with adoptive transfer of allogeneic hematopoietic stem cell transplant donor-derived virus-specific T cell lines in 153 recipients who received donor-derived EBV-specific CTLs (N=114), bivirus CTLs specific for adenovirus and EBV (n=14), and trivirus CTLs specific for CMV, adenovirus and EBV (n=25). Seventy three donor-recipient pairs were partially HLA-mismatched, with the degree of HLA mismatching varying from one allele to a full haplotype. De novo GvHD did not develop after infusion of cytotoxic T lymphocytes (CTL), and the incidence of GvHD reactivation was 6.5% and not significantly different between recipients of HLA matched or mismatched CTL. Thus, virus-specific CTL did not mediate GvHD, even in recipients of partially matched CTL. Next we analyzed the HLA alloreactivity of four donor-infused bivirus-specific T cell lines, using activated T cells, that are known to lack CMV and EBV antigen expression, as antigen presenting cells (TAPC). We used a panel of 44 TAPC covering the most frequent HLA class I and II alleles. The CTL lines were labeled with CFSE and stimulated with TAPC for 6 hours, after which production of TNFα and IFNγ/IL-2 by CD4+ and CD8+ T cells in the CFSE-positive fraction was analyzed by flow cytometry. All CTLs responded to a number of TAPC, with some APC being recognized strongly. The majority elicited only weak or no response from the CTLs. We then assessed whether the CTLs recognized TAPC expressing the recipient's HLA alleles. We found moderate reactivity of the CTL with 1–5 TAPC expressing recipient HLA alleles. Taken together, our data indicate that reactivity of virus-specific CTLs with hematopoietic APC does not correlate with the risk of developing GvHD, and that virus-specific CTL can safely be infused into HLA class I and/or II mismatched recipients. Disclosures: No relevant conflicts of interest to declare.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2236-2236
Author(s):  
Guenther Koehne ◽  
Deepa Trivedi ◽  
Roxanne Y. Williams ◽  
Richard J. O’Reilly

Abstract Cell-mediated immunity is essential for control of human cytomegalovirus (HCMV) infection. We utilized a pool of 138 synthetic overlapping pentadecapeptides over-spanning the entire pp65 protein to generate polyclonal CMV-specific T-cell lines from 12 CMV-seropositive donors inheriting different HLA genotypes. Autologous monocyte-derived dendritic cells (DCs) pulsed with this complete pool consistently induced highly specific T-cells and in analyses of T-cell lines from 5 separate HLA-A*0201+ individuals demonstrate that this pp65-derived pentadecapeptide-pool selectively induced T-cells specifically reactive against sub-pools of pentadecapeptides which contained the HLA-A*0201 binding epitope NLVPMVATV. The specificity of these T-cells for this immunodominant nonapeptide was confirmed by MHC-tetramer staining and intracellular interferon-γ production, demonstrating that 38 – 60% of the CD8+ cell population were specific for this A*2-restricted peptide after 3 weeks of culture. These T cells also killed both nonapeptide-pulsed and CMV-infected target cells. In subsequent experiments using auotlogous monocyte-derived DC’s pulsed with the pentadecapeptide pool for the stimulation of CMV-specific T-cell lines in individuals other than HLA-A*2, the generated T cells selectively recognized 1–3 pentadecapeptides identified by secondary responses to a mapping grid of pentadecapeptide subpools with single overlaps. Responses against peptide loaded targets sharing single HLA class I or II alleles permitted the identification the restricting HLA alleles. Those T-cell lines from HLA-A*2 neg. donors contained high frequencies of CD4 and/or CD8 T-cells selectively reactive against peptides presented by other HLA alleles including known epitopes such as aa 341–350QYDPVAALF (HLA-A*2402) as well as unreported epitopes such as aa 267–275HERNGFTVL (HLA-B*4001 and B* 4002). In some donors, the peptide-specific IFN-g+ T-cells generated have been predominantly CD4+ T-cells. Like the peptide-specific CD8+ T-cells, we could determine both epitope and HLA-class II restricting element, e.g. aa513–523 FFWDANDIYRI (HLA-DRB1* 1301). These CD4+ T-cells also consistently exhibited cytotoxic activity against infected targets as well as peptide-loaded cells expressing the restricting HLA class II allele. Thus, synthetic overlapping pentadecapeptides spanning the sequence of the immunodominant protein of CMV-pp65, when loaded on DCs can consistently stimulate the in vitro generation of CD8+ and CD4+ T-cell lines from seropositive donors of diverse HLA genotypes. These cell lines are selectively enriched for T-cells specific for a limited number of immunodominant epitopes each presented by a single HLA class I or class II allele. This approach fosters expansion and selection of HLA-restricted CMV-pp65-reactive T-cell lines of high specificity which also lyse CMV-infected targets and may have advantages for generating virus-specific T-cells for adoptive immunotherapy.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3873-3873
Author(s):  
Ekaterina Doubrovina ◽  
Jacob Dupont ◽  
Deepa Trivedi ◽  
Elena Kanaeva ◽  
Richard J. O’Reilly

Abstract The oncofetal protein, WT1, is differentially expressed in 60–80% of acute leukemias and CML. Previously, four peptide epitopes presented by HLA-A0201 or HLA-A2402 have been identified. We used a pool of 15-mers with 10 amino acid overlaps spanning the full sequence of WT1, loaded on autologous monocyte-derived dendritic cells or EBV-transformed BLCL to sensitize and raise T cell lines from a series of normal donors expressing or not expressing HLA-A0201 or HLA-A2402. Specific 15-mers eliciting responses were identified by quantitating IFNg+ CD8+ or CD4+ T cell responses to secondary stimulation with 15-mer subpools organized in a mapping grid with single overlaps. Responses against targets loaded with the identified stimulating 15-mer and sharing single HLA class I or II alleles permitted identification of restricting HLA alleles. Patients inheriting HLA-A0201 have generated CD8+ T cells in response to the complete pool which are selectively reactive against single 15-mers containing the known immunogen 252–260RMFPNAPYL. However, in certain donors, responses to 15-mer 28, containing a heretofore unreported epitope 136–144ALLPAVPSL, (which has a high predicted affinity for HLA-A0201) have been dominant. By mapping responses of T cells sensitized with the complete pool, defining the presenting HLA alleles and delineating immunogenic sequences within specific 15-mers, additional novel epitopes presented by HLA- B0801 and DRB10301 have also been defined. T cells generated by this approach also lyse both peptide-loaded targets as well as primary WT1+ leukemic cells expressing the restricting HLA allele. Thus, sensitization with pools of overlapping synthetic 15-mers spanning WT1 may selectively stimulate WT1-specific CD4+ and CD8+ T cell lines restricted by HLA alleles other than HLA- A0201 or A2402 that are leukemocidal and therefore of potential use for adoptive immunotherapy.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2876-2876
Author(s):  
Monica Ghei ◽  
David F. Stroncek ◽  
Maurizio Provenzano

Abstract In healthy subjects, primary infection with Cytomegalovirus (CMV) is usually mild or asymptomatic and is effectively controlled by the cell-mediated immune response. However, in immune compromised individuals, such as those with AIDS or after bone marrow transplantation, CMV reactivation is associated with significant morbidity until the individual’s immune system is completely reconstituted. One means of preventing post-transplant CMV infection is adoptive immunotherapy using CMV-specific cytotoxic T cells (CTLs) from the transplant donor. Several 9- and 10-mer HLA class I restricted peptides derived from the immune dominant CMV 65 kd matrix phosphoprotein (pp65) have been shown to produce CMV-specific CTLs. Two overlapping HLA-A24 restricted peptides have been specifically described: pp65 341–349 and pp65 341–350. These are 9- and 10-mer peptides that overlap except for the last amino acid phenylalanine (F) at the C-terminus [QYDPVAALF(F)]. Despite their similarity, the ability of these peptides to induce a T cell response has been reported to differ. Although it has been generally accepted that a unique CMV peptide is bound and presented by each separate HLA class I molecule, recent studies suggest that certain peptides are more promiscuous and may be presented by more than one HLA Class I antigen. For example, the 9-mer pp65 341–349 has been shown to stimulate CTLs from both HLA-A24 and Cw4 donors, while the 10-mer pp65 341–350 has been shown to be reactive with both HLA-A24 and A1 donors. The current investigation sought to compare the potency of these two peptides and determine the optimum peptide size for effective CMV adoptive immune therapy. Both peptides were tested for their ability to stimulate CMV-specific CTLs in HLA-A24, HLA-A1, and HLA-Cw4 restriction. In addition, a pp65 16-mer that included the 9- and 10-mers was tested for its ability to reactivate either CD8+ or CD4+ memory T cells. IFN-γ mRNA transcript as well as protein production were measured by in vitro cell culture assays. Peptide stimulations were performed on isolated CD8 and CD4 T lymphocytes by inducing the cells for 3 hours after a 2-week in vitro sensitization. The goal of the investigation was to determine whether both the 9- and the 10-mer peptides maintained high levels of CTL stimulation over time for all HLA restrictions studied. Moreover, it was important to investigate whether stimulation with the 16-mer, followed by restimulation by the two smaller peptides embedded within the larger sequence, led to effective T cell memory immune response. The 9- and 10-mer peptides effectively stimulated CTLs from HLA-A24, HLA-A1, and HLA-Cw4 CMV seropositive donors. Although both 9- and 10-mer were able to maintain high levels of stimulation over time for all restrictions, the 9-mer induced highest responses in cells expressing HLA-A24 (S.I. 4.07–528) or HLA-Cw4 (S.I. 4.15–483) while the 10-mer induced highest responses in cells expressing HLA-A24 (S.I. 3.5–528) or HLA-A1 (S.I. 8.25–615). The 16-mer peptide was also able to stimulate T cells from all HLA-A24, A1 and Cw4 donors (S.I. 6.95, 4.96, 5.02) at levels that are well maintained over time. This data confirmed that both the 9- and the 10-mer peptides are promiscuous and not restricted to a single HLA antigen. These peptides that have the ability to produce CMV-specific CTLs in patients with several different HLA types present a practical advantage over peptides that are restricted only to a single HLA type, and thus are optimal for CMV adoptive immune therapy.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3249-3249
Author(s):  
Avital L. Amir ◽  
Lloyd J.A. D’Orsogna ◽  
Marleen M. van Loenen ◽  
Dave L. Roelen ◽  
Ilias I.N. Doxiadis ◽  
...  

Abstract Graft versus host disease (GVHD) in allogeneic stem cell transplantation (SCT) and graft rejection is caused by alloreactive T-cells. Alloreactivity can be exerted by naïve as well as by memory T-cells. Persistent latent viral infections, like those with herpes viruses, have a profound impact on the repertoire of memory T-cells. This implies that virus specific memory T-cells are also potentially alloreactive. Previously it has been shown that virus specific T-cell clones can cross react against allo-HLA. We investigated the frequency of alloreactivity mediated by virus specific T-cells. Mixed lymphocyte reactions, previously used to determine precursor frequencies of alloreactive T-cells, give an underestimation of the total frequency of alloreactive T-cells, due to limited number of allo-HLA alleles tested in this system. Therefore, in this study multiple CD8+ virus specific T-cells lines and clones were tested for alloreactivity against almost all frequent HLA class I and II alleles. From different healthy individuals we derived CD8+ virus specific T-cell lines, specific for Epstein Barr virus (EBV), Cytomegalovirus (CMV), Varicella Zoster virus (VZV) and Influenza virus (Flu) which were restricted to different HLA molecules. The generation of the T-cell lines and clones was performed by bulk sorting and single cell sorting, based on staining with viral peptide/MHC complex specific tetramers. The viral specificity of the expanded lines and clones was confirmed by tetramer staining and cytotoxicity and cytokine production assays. Polyclonality of the T-cell lines and monoclonality of the T-cell clones was confirmed by TCR Vβ analysis. Next, the T-cell lines and clones were screened for alloreactivity by testing against a panel of 29 different EBV transformed LCLs, together covering almost all frequent HLA class I and II molecules. 90% of tested virus specific T-cell lines and 40% of virus specific T-cell clones were found to be alloreactive, recognizing at least one of the allo-HLA alleles. For several lines and clones the specific recognized allo-HLA molecule was further identified using a panel of HLA typed target cells in combination with HLA specific blocking antibodies. Additionally, single HLA antigen expressing cell lines were used as target cells. Thus far we found EBV EBNA3A specific, HLA-A3 restricted T-cell clones to recognize HLA-A31. A CMV pp50 specific, HLA-A1 restricted T-cell line recognized HLA-A68. One VZV IE62 specific, HLA-A2 restricted clone showed recognition of HLA-B57, while another clone with the same specificity but with a different TCR Vβ recognized HLA-B55. An EBV BMLF specific, HLA-A2 restricted T-cell line showed recognition of HLA-A11. Finally an EBV BRLF specific, HLA-A3 restricted clone recognized HLA-A2. Our results show that a high percentage of virus specific T-cells can exert alloreactivity against allo- HLA molecules. Previously it was assumed that virus specific T-cells are not alloreactive against foreign HLA, allowing safe application of virus specific T-cell lines derived from HLA disparate donors in patients without the risk of inducing GVHD. Our data indicate that applying virus specific T-cell lines over HLA barriers does give a significant risk of GVHD and suggest that lines should be tested for alloreactivity against patient specific HLA alleles prior to application. A substantial part of the memory T-cell pool consists of virus specific T-cells, which are dominated by a limited repertoire of virus specific T-cell clones, present in high frequencies. Thus, virus specific T-cells recognizing allo-HLA alleles may also play an essential role in graft rejection.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2048-2048
Author(s):  
Wesley Huisman ◽  
Didier A.T. Leboux ◽  
Lieve E. van der Maarel ◽  
Lois Hageman ◽  
Derk Amsen ◽  
...  

Abstract Reactivations of cytomegalovirus (CMV), Epstein Bar virus (EBV) and adenovirus (AdV) are frequently seen in immune compromised patients after allogeneic stem cell transplantation (alloSCT), and are associated with high morbidity and mortality. T cell immunity is essential for anti-viral protection, but a fully competent T cell repertoire generally does not develop until 3-6 months after transplantation. Especially patients transplanted with a virus non- experienced donor are at risk of developing severe complications. Adoptive transfer of partially HLA-matched virus specific T cells from healthy third party donors is a potential strategy to temporarily provide anti-viral immunity to these patients. However, these partially HLA-matched T cells harbor a risk of mediating allo-HLA cross-reactivity. Here, we investigated whether virus specificity and HLA restriction of the virus specific T cells influence the risk of allo-HLA cross-reactivity, and thus the development of GVHD. To determine the occurrence and diversity of allo-HLA cross-reactivity, virus specific CD8 T cells from homozygous HLA-A*01:01/B*08:01 and HLA-A*02:01/B*07:02 donors were isolated by cell sorting using tetramers for various peptides from CMV, EBV and AdV. Allo-HLA cross-reactivity was tested using an allogeneic EBV-LCL panel covering 116 different HLA molecules and confirmed using K562 cells retrovirally transduced with single HLA alleles of interest. A significant proportion of the virus specific T cell populations (n=174; 20 specificities) isolated from 27 healthy donors exerted allo-HLA cross-reactivity, as measured by recognition of 1 or more HLA mismatched EBV-LCLs from the panel. Similar frequencies were found for the various viral specificities showing 30% of the CMV, 46% of the EBV and 36% of the AdV-specific T cell populations to be allo-HLA cross-reactive. However, for some specificities (e.g. HLA-A*0201-restricted EBV-LMP2-FLY) allo-HLA cross-reactivity was infrequent (n=1/11), whereas for other specificities (e.g. HLA-B*08:01-restricted EBV-BZLF1-RAK) the majority of the T cell populations (n=9/13) was allo-HLA reactive. Surprisingly, a much larger fraction of HLA-B*08:01 restricted virus specific T cell populations showed allo-HLA cross-reactivity (72%, 36 out of 50 T cell lines), compared to the other HLA restricted virus specific T cell populations (29% of HLA-A*01:01, 30% of HLA-A*02:01 and 26% of HLA-B*07:02 restricted virus specific T cell lines). HLA-B*08:01 restricted virus specific T cells also exhibited the broadest allo-HLA reactivity, reacting to a median of 5 allo EBV-LCLs (range 1-17). In contrast, HLA-A*01:01, HLA-A*02:01 and HLA-B*07:02 restricted virus specific T cells reacted to a median of 1, 2 and 3 (ranges 1-7) allo EBV-LCLs, respectively. Dissection of the diversity/specificity of the allo-HLA reactivity using the panel of 40 different single HLA transduced K562 cells further illustrated the extensive allo-HLA cross-reactivity for HLA-B*08:01 restricted T cells isolated from homozygous HLA-A*01/B*08 donors compared to virus specific T cells restricted by other HLA alleles. These data show that allo-HLA cross-reactivity by virus specific T cells is highly influenced by the HLA restriction and not by the viral specificity of the T cell populations. Of the HLA-A*01, A*02, B*07 and B*08-restricted virus specific T cell populations isolated from homozygous donors, HLA-B*08:01 restricted virus specific T cells showed the highest frequency and diversity of allo-HLA cross-reactivity. Our results indicate that selection of virus specific T cells with specific HLA restrictions may decrease the risk of developing GVHD after infusion of third-party virus specific T cells to patients with uncontrolled viral reactivation after alloSCT. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4993-4993
Author(s):  
Eva Distler ◽  
Simone Thomas ◽  
Elke Schuerer ◽  
Cedrik Britten ◽  
Martin Schuler ◽  
...  

Abstract Diagnosis of graft-versus-host disease (GVHD) is mainly based on clinical features and on tissue biopsies. However, clinicians and pathologists are well aware of cases, in which GVHD cannot be distinguished from infections arising from severe immunodeficiency after allogeneic stem-cell transplantation (SCT). This may pose a deep therapeutic dilemma of whether to modify immunosuppressive treatment or to use donor lymphocyte infusion (DLI) for promoting anti-microbial immunity. We observed a 68-year-old patient with myelodysplastic syndrome who developed acute GVHD grade II of skin and gut at d+16 after T-cell depleted reduced-intensity SCT (Fig. 1). GVHD was confirmed by histology and responded to prednisolone therapy. From d+90 to d+240, the patient suffered from massive diarrhea (>2L per day) and recurrent episodes of lower gastrointestinal bleeding. Histopathology analysis on gut biopsies showed a heterogeneous picture with signs of GVHD and ulcerative inflammation. In stool screening, we isolated norovirus type 2 (ELISA, PCR) between d+111 and d+229, thereby confirming the longest infection with this virus ever reported. Tapering immunosuppression did not improve diarrhea, and the patient required intensive care due to serious fluid imbalance. Because of severe lymphopenia (<100 per μL CD3 T cells), we considered DLI therapy to promote T cell reconstitution and norovirus clearance. To balance the risk for DLI-induced exacerbation of GVHD, we first analyzed peripheral blood CD8 T cells for anti-recipient reactivity ex vivo by IFN-γ ELISPOT assay. Due to the limited availability of recipient cells and a single HLA disparity between donor (B*3508) and patient (B*3503), we used HLA-deficient K562 cells transfected with mismatched (B*3503) or matched (A*0201) HLA alleles as antigen-presenting cells. Post-transplant CD8 T cells specifically recognized disparate HLA-B*3503 (Fig. 1), but not shared HLA-A*0201. Mismatch-reactive CD8 T cells were detectable at significant numbers (71/105) during the first episode of GVHD and correlated closely with the intensity of diarrhea beyond d+110. Maximum anti-HLA-B*3503 reactivity (439/105) on d+205 was in the range of IFN-γ spot production obtained in mitogen-stimulated controls. Considering this vigorous alloreactivity, we were concerned that scheduled DLI would boost GVHD rather than facilitating norovirus clearance. Therefore, we decided to omit DLI. Patient’s clinical condition improved spontaneously around d+240, and diarrhea did not recur thereafter. In conclusion, we have established a new T cell assay for the rapid detection of anti-HLA mismatch reactivity using K562-HLA transfectants as substitutes for patient cells. In the meantime, we have validated this assay in two further HLA-incompatible donor-patient pairs and generated off-the-shelf K562 transfectants for more than 15 HLA alleles. Ex vivo alloreactivity toward mismatch HLA might be a surrogate marker to facilitate GVHD diagnosis and guide therapy in ambiguous clinical situations, such as the coincident viral infection described herein. Fig. 1: Clinical course and monitoring of all-HLA-B*3503 reactive CD8 T cells ex vivo Fig. 1:. Clinical course and monitoring of all-HLA-B*3503 reactive CD8 T cells ex vivo


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2021-2021
Author(s):  
Aisha N. Hasan ◽  
Ekaterina Doubrovina ◽  
Guenther Koehne ◽  
Susan E. Prockop ◽  
Richard J. O'Reilly

Abstract Adoptive transfer of virus-specific T-cells (CTLs) derived from allogeneic HLA partially matched third party donors can also be effective in a proportion of patients developing EBV lymphomas, or infections due to CMV or adenovirus following transplants from seronegative donors. Such third party donor derived CTLs offer an off the shelf reagent for treatment of viral infections developing after transplant. However, the immunodominant cytotoxic activity exhibited by the CTLs is directed against specific epitopes of the viral protein and restricted by 1-2 HLA alleles. Therefore, it is critical that the T-cells administered from third party donors can recognize viral epitopes presented on shared HLA alleles. We have established a bank of 119 CMV specific T-cell lines (CMV CTLs) generated using autologous APCs loaded with a pool of overlapping peptides spanning the sequence of the dominant immunogenic protein CMVpp65. Each of these 119 CMV CTL lines has been characterized as to the epitope inducing T-cell response as well as the HLA allele restricting the epitope specific T-cell response. Epitopes were identified using an overlapping grid of peptide pools and the HLA restriction by cytotoxic activity against peptide loaded EBVBLCLs matched at a single HLA allele with the T-cell donor. The distribution of the common HLA alleles among the donors for these CTL lines was predominantly within the distribution of HLA allele frequencies represented in the caucasian and black populations, except for HLA A0201 and B0702, which were over represented ( 33% vs 25% and 21% vs 8.7% respectively). In 54% of the CTL lines, the immunodominant T-cell responses were restricted by HLA A0201 (25%), B0702 (21%) and B 3501-11(8%), and in the remaining 50%, the responses were restricted by other HLA class-I alleles, while only 16/119 lines (13%) were restricted by HLA class-II alleles. All 25 donors inheriting HLA B0702 (25/25) demonstrated HLA B0702 restricted CMV CTL responses, while 30/39 (77%) donors inheriting HLA A0201 and 9/19 (47%) donors inheriting HLA B3501-11 demonstrated HLA A0201 and B3501-11 restricted CMV CTL responses. Among all 9 donors co-inheriting HLA A0201 and B 0702, the immunodominant T-cell response was restricted by B0702. Among 12 donors co-inheriting A0201 and B 4401-04, 11/12 (91.6%) demonstrated immunodominant CMV CTL responses restricted by A0201; 1 donor also co-inherited HLA B0702 whose response was restricted by B0702. Therefore, an immunodominance hierarchy for HLA class-I alleles presenting the dominant CMVpp65 epitope was evident through this analysis among these 119 donors and was as follows: B 0702, A0201, B3501-11, A2601, B44, B40, B4201, A0101, B 1801. Strikingly, only 1 of 119 donors demonstrated T-cell responses restricted by A1101; a commonly inherited HLA class –I allele. In a series of 239 consecutive HLA matched related or unrelated transplants (MUD) and 137 HLA mismatched unrelated (MMUD) transplants, and 100 cord blood transplants conducted at our center, in 86%, 89% and 80% of the cases respectively, we could identify a CMV CTL line restricted by a shared HLA allele and matched at 2-3 alleles within this GMP grade CTL bank that would be immediately available for treatment of CMV infection. Appropriately restricted CMV CTLs would only be available in 60-70% of MMUD transplant and none of the cord blood transplants without this approach. This CMV CTL bank therefore represents a readily available clinical reagent for the treatment of resistant CMV infections developing in post transplant patients. The characterization of the CTLs has also enabled the further elucidation of immunodominant CMVpp65 epitopes and hierarchies. Since we have previously shown that CMV CTLs can be generated against subdominant epitopes presented by both common HLA alleles as well as less prevalent HLA alleles using a panel of artificial antigen presenting cells (AAPCs), expansion of this bank using T-cell sensitized against CMVpp65 presented on such AAPCs should broaden the applicability of this bank to all HSCT recipients. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
1998 ◽  
Vol 92 (8) ◽  
pp. 2963-2970 ◽  
Author(s):  
Xue-Zhong Yu ◽  
Paul J. Martin ◽  
Claudio Anasetti

Because CD28-mediated T-cell costimulation has a pivotal role in the initiation and maintenance of T-cell responses, we tested the hypothesis that CD28 is critical for the development of graft-versus-host disease (GVHD). We compared the in vivo effects of CD28−/− T cells transplanted from B6 donor with the CD28 gene deleted by homologous recombination with those of CD28+/+ T cells transplanted from wild-type C57BL/6 (B6) donor. Fifty million CD28−/− or CD28+/+ splenocytes from B6 mice were transplanted into unirradiated (B6 × DBA/2)F1 (BDF1) recipients. Unlike CD28+/+, CD28−/− T cells from B6 mice had lower levels of proliferation and interleukin-2 production, had a limited ability to generate cytotoxic T lymphocytes against the recipient, and did not induce immune deficiency, despite survival in the recipient for at least 28 days. The ability to prevent rejection was reduced by the absence of CD28, because as many as 1.0 × 107 CD28−/− CD8+ cells were needed to prevent rejection of major histocompatibility complex (MHC) class-I incompatible marrow in sublethally irradiated (550 cGy) bm1 recipients, whereas 8.0 × 105 CD28+/+CD8+ T cells were sufficient to produce a similar effect, indicating that CD28 on donor CD8+ cells helps to eliminate host immunity. Two million CD4+CD28−/− or CD28+/+ T cells were transplanted into sublethally irradiated (750 cGy), MHC class-II incompatible (B6 × bm12)F1 recipients. With CD28−/−cells, 44% of the recipients died at a median of 20 days compared with 94% at a median of 15 days with CD28+/+ cells (P < .001). Two million CD8+CD28−/− or CD28+/+ T cells were transplanted into sublethally irradiated (750 cGy), MHC class-I incompatible (B6 × bm1) F1 recipients. With CD28−/−cells, 25% of the recipients died at a median of 41 days compared with 100% at a median of 15 days with CD28+/+ cells (P < .001). (B6 × bm12)F1 and (B6 × bm1)F1 mice surviving after transplantation of CD28−/− cells recovered thymocytes, T cells, and B cells in numbers and function comparable with that of irradiation-control F1 mice. We conclude that CD28 contributes to the pathogenesis and the severity of GVHD. Our results suggest that the severity of GVHD could be decreased by the administration of agents that block CD28 function in T lymphocytes. © 1998 by The American Society of Hematology.


Blood ◽  
2005 ◽  
Vol 105 (7) ◽  
pp. 2793-2801 ◽  
Author(s):  
Deepa Trivedi ◽  
Roxanne Y. Williams ◽  
Richard J. O'Reilly ◽  
Guenther Koehne

Abstract Cell-mediated immunity is essential for control of human cytomegalovirus (HCMV) infection. We used a pool of 138 synthetic overlapping pentadecapeptides overspanning the entire pp65 protein to generate polyclonal CMV-specific T-cell lines from 12 CMV-seropositive donors inheriting different HLA genotypes. Autologous monocyte-derived dendritic cells (DCs) pulsed with this complete pool consistently induced highly specific T cells that selectively recognized 1-3 pentadecapeptides identified by secondary responses to a mapping grid of pentadecapeptide subpools with single overlaps. Responses against peptide-loaded targets sharing single HLA class I or II alleles identified the restricting HLAalleles. HLA-A*0201+ donors consistently responded to pentadecapeptides containing HLA-A*0201-binding epitopeaa495-503NLVPMVATV. T-cell lines from other donors contained high frequencies of CD4 and/or CD8 T cells selectively reactive against peptides presented by other HLA alleles, including both known epitopes such as aa341-350QYDPVAALF (HLA-A*2402) as well as unreported epitopes such as aa267-275HERNGFTVL (HLA-B*4001 and B*4002) and aa513-523FFWDANDIYRI (HLA-DRB1*1301). These T cells consistently lysed CMV-infected target cells. Thus, this approach fosters expansion and selection of HLA-restricted CMV-pp65–reactive T-cell lines of high specificity that also lyse CMV-infected targets, and from a functional and regulatory perspective, may have advantages for generating virus-specific T cells for adoptive immunotherapy.


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