scholarly journals CMV-Specific T Cells Restricted By Shared and Donor, but Not By Host HLA Molecules Reconstitute in the First 180 Days after Allogeneic HSCT and Protect from CMV Reactivation: Results of a Prospective Observational Study

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4536-4536
Author(s):  
Maddalena Noviello ◽  
Elena Tassi ◽  
Pantaleo De Simone ◽  
Francesca Serio ◽  
Maria Teresa Lupo Stanghellini ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Observational Study ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Absolute Number ◽  
T Cell Response ◽  
T Cell Reconstitution ◽  
The Absolute ◽  
Cmv Reactivation

Introduction: Cytomegalovirus (CMV) reactivation and disease are important risk factors after allogeneic hematopoietic stem cell transplantation (allo-HSCT), and strongly affect morbidity and mortality after transplant. CMV-specific T cell reconstitution controls CMV reactivation and protects against serious adverse events but a protective level of CMV-specific T cell response or standardized method for its monitoring have not been yet determined. Methods: We designed a prospective, single-center observational study to assess if the kinetic and quality of CMV specific T-cell reconstitution impact the incidence and severity of CMV reactivations. We have enrolled 84 consecutive patients affected by hematological malignancies receiving allo-HSCT followed by Cyclophosphamide and Rapamycin between December 2017 and February 2019. Here we report preliminary data on the first 61 patients. Patients received allo-HSCT from family (siblings=10; HLA haploidentical=24), unrelated HLA-matched (n= 24) donors or cord blood (CB, n=3). The CMV serostatus of host (H) and donor (D) pairs was: H+/D+(n=40, 65%), H+/D-(n=20, 33%) and H-/D+ (n=1, 2%); H-/D-(7% of the overall transplanted population at our center) were excluded. CMV DNAemia was assessed weekly in whole blood (WB). Absolute numbers of polyclonal and CMV-specific T cells were quantified by flow cytometry using Troucount™Tubes (BD) and Dextramer®CMV-Kit (Immudex), respectively, in the graft and fresh WB at days -7, +30, +45, +60, +90, +120, +150, +180 and +360. Dextramer CMV kit includes reagents for the identification of CMV-specific lymphocytes restricted for several HLA class I molecules: A*01:01/*02:01/*03:01/*24:02 and B*07:02/*08:01/*35:01. These alleles allowed the longitudinal evaluation of 54 out of 61 (89%) patients. Results: At a median follow-up of 226 days post-HSCT, 31 (57%) patients experienced a CMV-related clinically relevant event (CRE, median +63 days), including 8 patients (15%) with CMV disease (median +59 days). Univariate analyses showed that the incidence of CMV clinically-relevant reactivation (CRE) was influenced by H/D CMV serostatus (0.90 in H+/D- versus 0.44 in H+/D+pairs, p=0.015) and by previous acute Graft-versus-Host Disease (aGvHD) requiring systemic immunosuppression (0.82 in aGvHD grade II-IV versus 0.52 in aGvHD grade 0-I, p=0.051). The disease status at transplant, the donor type (HLA-matched versus HLA-haploidentical/CB donors), donor's or host's age did not significantly affect the probability to develop CRE. For each time-point, we compared the absolute number of CMV-specific lymphocytes in patients experiencing or not a subsequent CRE. Our data demonstrate that higher levels of CMV-specific CD8+T cells in the donor apheresis and at +45 days after allo-HSCT are associated with reduced risk of subsequent CRE (median CMV-specific CD8+cells/kg in the apheresis=5x103in CRE-positive patients (CRE+) and 5x105in CRE-negative patients (CRE-), p=0.012; median CMV-specific CD8+at +45 days=0.14 cells/μL in CRE+and 1.21 cells/μL in CRE-, p=0.034). Furthermore, patients with any Dextramer positivity at +45 days displayed a lower incidence of CRE compared with subjects who were negative (CRE probability: 0.5 vs 1.0, p=0.003). Conversely, the absolute number of neither polyclonal CD3+CD8+T lymphocytes nor total CD3+T cells correlate with subsequent CRE. Taking advantage of the HLA mismatched-HSCT setting, we then dissected CMV-specific T-cell response according to HLA restriction elements (H/D=shared n=45, D-restricted n=14, H-restricted n=11). In H+/D+pairs, we observed a fast and similar kinetic of reconstitution of CMV-specific lymphocytes restricted by H/D and D HLAs. Conversely, in H+/D-pairs, we detected only CMV-specific CD8+lymphocytes restricted for H/D haplotypes. Host-restricted cells remained undetectable for the first 180 days after HSCT. Conclusion: Early after allo-HSCT and in the donor apheresis, the level of CMV-specific CD8+T cells measured by Dextramer staining differs in patients experiencing or not subsequent CRE. Furthermore, our findings indicate that CMV reactivations can prime H/D-restricted T cells presumably educated in the donor thymus; conversely, D- and H-restricted donor-derived lymphocytes have not yet undergone neither cross-priming nor thymic education respectively. Disclosures Brix: Immudex: Employment. Bonini:Kite/Gilead: Consultancy; Intellia Therapeutics: Consultancy; Intellia Therapeutics: Research Funding; Novartis: Consultancy; GSK: Consultancy; Allogene: Consultancy; Molmed: Consultancy; TxCell: Consultancy; -: Patents & Royalties: Adoptive T cell therapy field.

Recovery of CMV-Specific T Cells Following Alternative Donor Allogeneic Transplant with Post-Transplant Cyclophosphamide

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5462-5462
Author(s):  
Ayman Saad ◽  
Samantha B Langford ◽  
Shin Mineishi ◽  
Lawrence S. Lamb
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Recovery ◽  
Post Transplant ◽  
Increased Risk ◽  
Cmv Reactivation

Abstract Background: Post-transplant cyclophosphamide (PTCy) is increasingly used for GVHD prophylaxis after allogeneic hematopoietic stem cell transplantation (HCT) using alternative donors. However, immune reconstitution can be delayed posing an increased risk for CMV reactivation. We evaluated the outcomes of patients who received HCT-apheresis products comparing the impact of PTCy on lymphocyte recovery, CMV reactivation and CMV-specific CD8+ T cell recovery following haplo-identical (HAPLO), matched unrelated donor (MUD), and mismatched unrelated donor (mMUD) grafts vs. with conventional matched related donor (MRD) graft recipients. Methods: We examined 26 patients (median age, 49 years; range, 20-72 years) with advanced hematologic malignancies; n=5 (HAPLO); 6 (MRD); 15 (MUD). All patients received myeloablative conditioning regimens that was either busulfan- or total body irradiation (TBI)-based. PTCy (50 mg/kg/day) was administered on days +3 and +4 following HAPLO and on day +3 following MUD/mMUD transplant. Peripheral blood lymphocyte reconstitution and frequency of circulating CMV-directed CD8+ T cells was assessed (day ± 10 days) on post-transplant days +30, +60, and +90. Circulating anti-CMV T cell frequency was assessed using a phycoerythrin-tagged MHC dextramer against HLA-specific CMV pp65, IE-1, or pp50 peptides (Immudex; Copenhagen, DK) in combination with Tru-Count¨ tubes and fluorescent-labeled monoclonal antibodies against CD3, CD8, CD4, CD16/56, and CD19 (BD Biosciences; San Jose, CA). Anti-CMV CD8+ T cell immunity was defined as a CMV-dextramer (CMV/DEX) positive count of ≥7cells/ml. CMV reactivation was defined as a serologic titer of >500IU/mL. All patients with CMV reactivation received ganciclovir therapy until CMV titer became negative. Results: Day +30 total T cell recovery was significantly faster in MRD than CY-treated recipients (p=0.015) due principally to more robust CD8+ T cell recovery. CD4 T cell recovery remained below normal range in all groups through day +100. NK cells recovered to normal numbers at day +28 in all groups. Neither PTCy nor donor source significantly impacted the percentage of patients that recovered anti-CMV CD8+ T cells at each time interval (p = 0.8232). Excluding donors (D) and recipients (R) that were both negative, CMV/DEX+ T cells recovery was >7/mL in 4/5 MRD, 7/14 MUD, and 3/5 HAPLO by day +100. Among MRD recipients either D+ or R+ (n=5), 2 patients showed CMV reactivation within 40 days of transplant that was associated with <7 CMV/DEX+ T cells on day +30. Subsequent high (>90/mL) CMV/DEX T cell response in one patient shortened the duration of viremia to 10 days (vs. 16 days with poor responder) and 3 patients showed no CMV reactivation and a high CMV/DEX+ T cell response by day +60. For MUD CMV D+ and/or R+ recipients (n=14), 3 showed CMV reactivation within 50 days of transplant. All 3 patients had suboptimal CMV/DEX T cell response on day +30. Robust CMV/DEX+ T cell response on day +60 predicted shorter duration of viremia (20 days vs. average of 32 days). For HAPLO CMV D+ and/or R+ (n=5) recipients, 4 experienced CMV reactivation within 50 days of transplant. All patients had a <7 CMV/DEX+ T cells/mL +30. Robust CMV/DEX+ T cell response by day +60 was associated with shorter duration of viremia (range 7-21 days), while one patient with <7/mL CMV/DEX+ T cells had continued CMV viremia for 36 days. Conclusion: In this preliminary analysis, neither PTCy nor donor source significantly impacted the percentage of patients that recovered anti-CMV CD8+ T cells at each time interval. A weak CMV/DEX+ response (<7 cells/mL) on day +30 was consistent with increased risk of CMV reactivation (viremia) in all groups. A CMV/DEX+ T cell count ≥7 cells/mL was not immediately protective against CMV reactivation, but higher counts were associated with a shortened duration of viremia while on antiviral therapy. Conversely, subnormal counts were associated with a longer duration of viremia. This interim analysis suggests that CMV/DEX+ T cell enumeration is a useful biologic correlate for determining clinical response to antiviral therapy, and that donor-derived CMV specific T cell immunity is not further compromised with following PTCy in alternative donor HCT. Disclosures No relevant conflicts of interest to declare.

scholarly journals Type I Interferons Regulate the Magnitude and Functionality of Mouse Polyomavirus-Specific CD8 T Cells in a Virus Strain-Dependent Manner

2016 ◽  
Vol 90 (10) ◽  
pp. 5187-5199 ◽  
Author(s):  
Qingsong Qin ◽  
Shwetank ◽  
Elizabeth L. Frost ◽  
Saumya Maru ◽  
Aron E. Lukacher
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Single Amino Acid ◽  
Type I ◽  
Type I Ifns ◽  
Vp1 Capsid Protein

ABSTRACTMouse polyomavirus (MPyV) is a ubiquitous persistent natural mouse pathogen. A glutamic acid (E)-to-glycine (G) difference at position 91 of the VP1 capsid protein shifts the profile of tumors induced by MPyV from an epithelial to a mesenchymal cell origin. Here we asked if this tropism difference affects the MPyV-specific CD8 T cell response, which controls MPyV infection and tumorigenesis. Infection by the laboratory MPyV strain RA (VP1-91G) or a strain A2 mutant with an E-to-G substitution at VP1 residue 91 [A2(91G)] generated a markedly smaller virus-specific CD8 T cell response than that induced by A2(VP1-91E) infection. Mutant A2(91G)-infected mice showed a higher frequency of memory precursor (CD127hiKLRG1lo) CD8 T cells and a higher recall response than those of A2-infected mice. Using T cell receptor (TCR)-transgenic CD8 T cells and immunization with peptide-pulsed dendritic cells, we found that early bystander inflammation associated with A2 infection contributed to recruitment of the larger MPyV-specific CD8 T cell response. Beta interferon (IFN-β) transcripts were induced early during A2 or A2(91G) infections. IFN-β inhibited replication of A2 and A2(91G)in vitro. Using mice lacking IFN-αβ receptors (IFNAR−/−), we showed that type I IFNs played a role in controlling MPyV replicationin vivobut differentially affected the magnitude and functionality of virus-specific CD8 T cells recruited by A2 and A2(91G) viral infections. These data indicate that type I IFNs are involved in protection against MPyV infection and that their effect on the antiviral CD8 T cell response depends on capsid-mediated tropism properties of the MPyV strain.IMPORTANCEIsolates of the human polyomavirus JC virus from patients with the frequently fatal demyelinating brain disease progressive multifocal leukoencephalopathy (PML) carry single amino acid substitutions in the domain of the VP1 capsid protein that binds the sialic acid moiety of glycoprotein/glycolipid receptors on host cells. These VP1 mutations may alter neural cell tropism or enable escape from neutralizing antibodies. Changes in host cell tropism can affect recruitment of virus-specific CD8 T cells. Using mouse polyomavirus, we demonstrate that a single amino acid difference in VP1 known to shift viral tropism profoundly affects the quantity and quality of the anti-polyomavirus CD8 T cell response and its differentiation into memory cells. These findings raise the possibility that CD8 T cell responses to infections by human polyomaviruses may be influenced by VP1 mutations involving domains that engage host cell receptors.

scholarly journals Role of Thymic Output in Regulating CD8 T-Cell Homeostasis during Acute and Chronic Viral Infection

2005 ◽  
Vol 79 (15) ◽  
pp. 9419-9429 ◽  
Author(s):  
Nicole E. Miller ◽  
Jennifer R. Bonczyk ◽  
Yumi Nakayama ◽  
M. Suresh
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Viral Infections ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Responses ◽  
Lcmv Infection

ABSTRACT Although it is well documented that CD8 T cells play a critical role in controlling chronic viral infections, the mechanisms underlying the regulation of CD8 T-cell responses are not well understood. Using the mouse model of an acute and chronic lymphocytic choriomeningitis virus (LCMV) infection, we have examined the relative importance of peripheral T cells and thymic emigrants in the elicitation and maintenance of CD8 T-cell responses. Virus-specific CD8 T-cell responses were compared between mice that were either sham thymectomized or thymectomized (Thx) at ∼6 weeks of age. In an acute LCMV infection, thymic deficiency did not affect either the primary expansion of CD8 T cells or the proliferative renewal and maintenance of virus-specific lymphoid and nonlymphoid memory CD8 T cells. Following a chronic LCMV infection, in Thx mice, although the initial expansion of CD8 T cells was normal, the contraction phase of the CD8 T-cell response was exaggerated, which led to a transient but striking CD8 T-cell deficit on day 30 postinfection. However, the virus-specific CD8 T-cell response in Thx mice rebounded quickly and was maintained at normal levels thereafter, which indicated that the peripheral T-cell repertoire is quite robust and capable of sustaining an effective CD8 T-cell response in the absence of thymic output during a chronic LCMV infection. Taken together, these findings should further our understanding of the regulation of CD8 T-cell homeostasis in acute and chronic viral infections and might have implications in the development of immunotherapy.

scholarly journals Contribution of Herpesvirus Specific CD8 T Cells to Anti-Viral T Cell Response in Humans

2010 ◽  
Vol 6 (8) ◽  
pp. e1001051 ◽  
Author(s):  
Elena Sandalova ◽  
Diletta Laccabue ◽  
Carolina Boni ◽  
Anthony T. Tan ◽  
Katja Fink ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
T Cell Response

scholarly journals CD4+CD8+T Cells Represent a Significant Portion of the Anti-HIV T Cell Response to Acute HIV Infection

2012 ◽  
Vol 188 (9) ◽  
pp. 4289-4296 ◽  
Author(s):  
Marc A. Frahm ◽  
Ralph A. Picking ◽  
JoAnn D. Kuruc ◽  
Kara S. McGee ◽  
Cynthia L. Gay ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Hiv Infection ◽  
Cd8 T Cells ◽  
Cell Response ◽  
T Cell Response ◽  
Acute Hiv Infection ◽  
Acute Hiv ◽  
Anti Hiv

scholarly journals Mucosal CD8+ T cell responses induced by an MCMV based vaccine vector confer protection against influenza challenge

2018 ◽  
Author(s):  
Xiaoyan Zheng ◽  
Jennifer Dora Oduro ◽  
Julia Désirée Boehme ◽  
Lisa Borkner ◽  
Thomas Ebensen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Influenza A ◽  
Clinical Medicine ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Vaccine Vector ◽  
Protective Capacity

Cytomegalovirus (CMV) is a ubiquitous β-herpesvirus that establishes life-long latent infection in a high percentage of the population worldwide. CMV induces the strongest and most durable CD8+ T cell response known in human clinical medicine. Due to its unique properties, the virus represents a promising candidate vaccine vector for the induction of persistent cellular immunity. To take advantage of this, we constructed a recombinant murine CMV (MCMV) expressing an MHC-I restricted epitope from influenza A virus (IAV) H1N1 within the immediate early 2 (ie2) gene. Only mice that were immunized intranasally (i.n.) were capable of controlling IAV infection, despite the greater potency of the intraperitoneally (i.p.) vaccination in inducing a systemic IAV-specific CD8+ T cell response. The protective capacity of the i.n. immunization was associated with its ability to induce IAV-specific tissue-resident memory CD8+ T (CD8TRM) cells in the lungs. Our data demonstrate that the protective effect exerted by the i.n. immunization was critically mediated by antigen-specific CD8+ T cells. CD8TRM cells promoted the induction of IFNγ and chemokines that facilitate the recruitment of antigen-specific CD8+ T cells to the lungs. Overall, our results showed that locally applied MCMV vectors could induce mucosal immunity at sites of entry, providing superior immune protection against respiratory infections.

scholarly journals Chimeric Yellow Fever/Dengue Virus as a Candidate Dengue Vaccine: Quantitation of the Dengue Virus-Specific CD8 T-Cell Response

2000 ◽  
Vol 74 (17) ◽  
pp. 8094-8101 ◽  
Author(s):  
Robbert G. van der Most ◽  
Kaja Murali-Krishna ◽  
Rafi Ahmed ◽  
James H. Strauss
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dengue Virus ◽  
Yellow Fever ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Protective Efficacy ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
E Proteins

ABSTRACT We have constructed a chimeric yellow fever/dengue (YF/DEN) virus, which expresses the premembrane (prM) and envelope (E) genes from DEN type 2 (DEN-2) virus in a YF virus (YFV-17D) genetic background. Immunization of BALB/c mice with this chimeric virus induced a CD8 T-cell response specific for the DEN-2 virus prM and E proteins. This response protected YF/DEN virus-immunized mice against lethal dengue encephalitis. Control mice immunized with the parental YFV-17D were not protected against DEN-2 virus challenge, indicating that protection was mediated by the DEN-2 virus prM- and E-specific immune responses. YF/DEN vaccine-primed CD8 T cells expanded and were efficiently recruited into the central nervous systems of DEN-2 virus challenged mice. At 5 days after challenge, 3 to 4% of CD8 T cells in the spleen were specific for the prM and E proteins, and 34% of CD8 T cells in the central nervous system recognized these proteins. Depletion of either CD4 or CD8 T cells, or both, strongly reduced the protective efficacy of the YF/DEN virus, stressing the key role of the antiviral T-cell response.

CLTA-4 blockadein vivopromotes the generation of short-lived effector CD8+T cells and a more persistent central memory CD4+T cell response

2008 ◽  
Vol 37 ◽  
pp. 62-68 ◽  
Author(s):  
David A. Hokey ◽  
Jian Yan ◽  
Lauren A. Hirao ◽  
Anlan Dai ◽  
Jean D. Boyer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
T Cell Response ◽  
Central Memory ◽  
Cd4 T Cell

T Cell Recognition of HCMV: Pan-Genome Analysis of Immunogenic Open-Reading Frames.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 606-606 ◽  
Author(s):  
Louis J. Picker ◽  
Andrew W. Sylwester ◽  
Bridget L. Mitchell ◽  
Cara Taormina ◽  
Christian Pelte ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
Cell Response ◽  
Cd8 T Cell ◽  
Cross Reactivity ◽  
T Cell Response ◽  
Cd4 T Cell ◽  
Cell Responses

Abstract Human Cytomegalovirus (HCMV) is among the largest and most complex of known viruses with 150–200nm virions enclosing a double stranded 230kb DNA genome capable of coding for >200 proteins. HCMV infection is life-long, and for the vast majority of immune competent individuals clinically benign. Disease occurs almost exclusively in the setting of immune deficiency, suggesting that the stable host-parasite relationship that characterizes these infections is the result of an evolutionarily “negotiated” balance between viral mechanisms of pathogenesis and the host immune response. In keeping with, and perhaps because of this balance, the human CD4+ T cell response to whole HCMV viral lysates is enormous, with median peripheral blood frequencies of HCMV-specific cells ~5–10 fold higher than for analogous preparations of other common viruses. Although certain HCMV ORFs have been identified as targets of either the CD4+ or CD8+ T cell response, the specificities comprising the CD4+ T cell response, and both the total frequencies and component parts of the CD8+ T cell response are unknown. Here, we used cytokine flow cytometry and ~14,000 overlapping 15mer peptides comprising all 213 HCMV ORFs encoding proteins >100 amino acids in length to precisely define the total CD4+ and CD8+ HCMV-specific T cell responses and the HCMV ORFs responsible for these responses in 33 HCMV-seropositive, HLA-disparate donors. An additional 9 HCMV seronegative donors were similarly examined to define the extent to which non-HCMV responses cross-react with HCMV-encoded epitopes. We found that when totaled, the median frequencies of HCMV-specific CD4+ and CD8+ T cells in the peripheral blood of the seropositive subjects were 4.0% and 4.5% for the total CD4+ or CD8+ T cell populations, respectively (which corresponds to 9.1% and 10.5% of the memory populations, respectively). The HCMV-specific CD4+ and CD8+ T cell responses included a median 12 and 7 different ORFs, respectively, and all told, 73 HCMV ORFs were identified as targets for both CD4+ and CD8+ T cells, 26 ORFs as targets for CD8+ T cells alone, and 43 ORFS as targets for CD4+ T cells alone. UL55, UL83, UL86, UL99, and UL122 were the HCMV ORFs most commonly recognized by CD4+ T cells; UL123, UL83, UL48, UL122 and UL28 were the HCMV ORFs most commonly recognized by CD8+ T cells. The relationship between immunogenicity and 1) HLA haplotype and 2) ORF expression and function will be discussed. HCMV-seronegative individuals were non-reactive with the vast majority of HCMV peptides. Only 7 potentially cross-reactive responses were identified (all by CD8+ T cells) to 3 ORFs (US32, US29 and UL116) out of a total of almost 4,000 potential responses, suggesting fortuitous cross-reactivity with HCMV epitopes is uncommon. These data provide the first glimpse of the total human T cell response to a complex infectious agent, and will provide insight into the rules governing immunodominance and cross-reactivity in complex viral infections of humans.

The Absence of Vasoactive Intestinal Peptide Augments Allo-Reactivity and the Anti-Viral Response in Bone Marrow Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3267-3267
Author(s):  
Lauren T. Southerland ◽  
Jian-Ming Li ◽  
Sohrab Hossain ◽  
Cynthia Giver ◽  
Wayne Harris ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Low Dose ◽  
T Cell Response ◽  
High Dose ◽  
Mcmv Infection

Abstract Background: The severe morbidity and mortality associated with bone marrow transplantation (BMT) is caused by uninhibited immune responses to alloantigen and suppressed immune responses to pathogens. Vasoactive Intestinal Peptide (VIP) is an immunomodulatory neuropeptide produced by T-cells and nerve fibers in peripheral lymphoid organs that suppresses immune responses by induction of tolerogenic dendritic cells. In order to determine the immunoregulatory effects of VIP, we examined T-cell immune responses to allo- and viral-antigens in VIP knockout (KO) mice and mouse BMT recipients of hematopoietic cells from VIP KO donors. Methods: VIP KO mice and VIP WT littermates were infected with lethal or sub-lethal doses (5 × 104− 5 × 105 PFU) of murine cytomegalovirus (mCMV) and the T-cell response to viral antigen was measured by flow cytometry for mCMV peptide-MHC class 1-tetramer+ CD8+ T-cells. We transplanted 5 × 106 BM plus 1 × 106 splenocytes (SP) either from VIP KO or VIP WT donors in an C57BL/6 to F1(BL/6 × Balb/c) allo-BMT model and assessed survival, GvHD, donor T-cell expansion, chimerism, and response to mCMV vaccination and mCMV infection. Results: B-cell, αβ and γδ T-cell, CD8+ T-cell, CD11b+ myeloid cell, and dendritic cell numbers were equivalent between VIP KO and WT mice, while VIP KO mice had higher number of CD4+ and CD4+CD62L+CD25+ T-cells. Non-transplanted VIP KO mice survived mCMV infection better compared to VIP WT, with a brisker anti-viral T-cell response in the blood. In the allogeneic BMT setting, recipients of VIP KO BM plus VIP KO SP had more weight loss and lower (40%) 100 day post-transplant survival compared to the recipients of VIP KO BM plus WT SP (80% survival), recipients of WT BM plus KO SP (100% survival), and recipients of WT BM plus WT SP (80% survival). Recipients of VIP KO grafts had a significantly greater anti-mCMV response that peaked four days earlier than the tetramer response of mice transplanted with WT cells. This increased anti-viral response to vaccination correlated with a greater and more rapid T-cell response to secondary viral challenge. Conclusions: These experiments suggest that the absence of all VIP in the body, or the absence of VIP in a transplanted immune system, enhances anti-viral immunity and allo-immune responses. Modulation of the VIP pathway is a novel method to regulate post-transplant immunity. Figure 1: VIP knockout(KO) mice have an increased CMV tetramer response. VIP KO and VIP WT mice were infected (day 0) with either a sub-lethal low dose (5 × 10^4 PFU) or a lethal high dose (5 × 10^5 PFU) of CMV. Peripheral blood was stained for T cell markers and tetramer and analyzed by flow cytometry. On day 3, high dosed VIP KO mice had a higher number of tetramer positive CD8 T cells and better survival than WT mice (all high dose VIP WT died prior to day 10). VIP KO mice had a significant increase in tetramer positive CD8 T cells between days 3 and 10. *** p<0.01, difference between VIP KO and VIP WT littermate at designated dose level and day. Figure 1:. VIP knockout(KO) mice have an increased CMV tetramer response. VIP KO and VIP WT mice were infected (day 0) with either a sub-lethal low dose (5 × 10^4 PFU) or a lethal high dose (5 × 10^5 PFU) of CMV. Peripheral blood was stained for T cell markers and tetramer and analyzed by flow cytometry. On day 3, high dosed VIP KO mice had a higher number of tetramer positive CD8 T cells and better survival than WT mice (all high dose VIP WT died prior to day 10). VIP KO mice had a significant increase in tetramer positive CD8 T cells between days 3 and 10. *** p<0.01, difference between VIP KO and VIP WT littermate at designated dose level and day.

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