Biomedical subjects

C J Boog

Publications and source records attributed to C J Boog.

At least 19 recordsLinked to original sources

PubMed2001

High IL-13 production by human neonatal T cells: neonate immune system regulator?

Neonates are highly susceptible to diseases and display biased type 2 immune responses, although no skewing to type 2 cytokines has been reported. In view of the emerging importance of IL-13 in type 2 inflammatory responses and clinical allergy, we analyzed IL-13 production by neonatal T cells. We found that, mainly CD8 T cells produced high levels of IL-13, while producing low levels of IL-4, IL-10 and IFN-gamma, upon primary and secondary stimulation. Our results point towards a possible immunoregulatory role of CD8 T cells in neonate responses. Moreover, they suggest that the abundance of IL-13 in the neonate immune system might account for the type 2 bias in neonates, providing a basis for the high disease susceptibility of newborns, for instance to allergic diseases.

CD8-Positive T-Lymphocytes↗

PubMed2000

T- and B-cell nonresponsiveness to self-alphaB-crystallin in SJL mice prevents the induction of experimental allergic encephalomyelitis.

The myelin-associated stress protein alphaB-crystallin triggers strong proliferative responses and IFN-gamma production by human T cells and it is considered a candidate autoantigen in multiple sclerosis. In this study we examined the capacity of alphaB-crystallin or peptides derived thereof to induce experimental autoimmune encephalomyelitis (EAE) in SJL mice. Despite extensive efforts to induce EAE using active immunization with whole alphaB-crystallin, using adoptive transfer of lymphocytes or using peptide immunizations, no clinical or histological signs of EAE could be induced. SJL mice were unable to mount proliferative T-cell responses in vitro or delayed-type hypersensitivity responses in vivo to self-alphaB-crystallin. Also, immunization with self-alphaB-crystallin did not lead to any antibody response in SJL mice while bovine alphaB-crystallin triggered clear antibody responses within 1 week. Immunizations with alphaB-crystallin-derived peptides led to the activation of IL-4-producing Th2 cells and only a few IFN-gamma-producing Th1 cells. Peptide-specific T cells showed no cross-reactivity against whole alphaB-crystallin. The inability of SJL mice to mount proinflammatory T-cell responses against self-alphaB-crystallin readily explains the lack of EAE induction by immunization with whole protein or peptides derived from it. T- and B-cell nonresponsiveness is associated with constitutive expression of full-length alphaB-crystallin in both primary and secondary lymphoid organs in SJL mice, which is seen in other mammals as well, but not in humans.

Adoptive Transfer↗

PubMed2000

Tolerance controls encephalitogenicity of alphaB-crystallin in the Lewis rat.

The myelin-associated protein, alphaB-crystallin, is considered a candidate autoantigen in multiple sclerosis (MS). In the present study, we examined the potential of alphaB-crystallin to induce experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Attempts to induce EAE with either bovine, rat or murine alphaB-crystallin or alphaB-crystallin peptides consistently failed. Immunization with either autologous rat or murine alphaB-crystallin did not trigger any antigen-specific T cell response. Immunization with bovine alphaB-crystallin or a synthetic peptide representing the cryptic epitope 49-64 did trigger T cell responses but these failed to crossreact with autologous rat alphaB-crystallin. Examination of lymphoid tissues of the Lewis rat revealed constitutive expression of alphaB-crystallin in thymus, spleen, and peripheral lymphocytes. Our data show that in Lewis rats, constitutive lymphoid expression of alphaB-crystallin is associated with a state of nonresponsiveness to autologous alphaB-crystallin that effectively controls the development of EAE in response to this myelin antigen.

Animals↗

PubMed2000

Modulation of the T cell receptor beta chain repertoire after heart transplantation.

BACKGROUND: In a previous study it was shown that pre-transplant blood transfusion was associated with a better clinical outcome after heart transplantation (HTx). In this study the effect of heart transplantation (HTx) on the T cell receptor V beta chain (TCRVbeta) repertoire was investigated. Therefore, we analyzed the TCRVbeta repertoire of patients after HTx to see whether a correlation with clinical outcome could be observed. METHODS: Patients were analyzed at four different time points: pre-HTx, less than 1 month post-Htx, between 1 month and 2.5 month post-Htx and more than 2.5 months post-HTx. CD4+ and CD8+ T cells were purified from patient peripheral blood mononuclear cells (PBMC). TCR beta chain usage was analyzed semiquantitatively by Southern blot analysis. RESULTS: HTx affected the TCRVbeta repertoire in both the CD4+ and CD8+ T cell compartments in all patients. Changes in the TCRVbeta repertoire were most pronounced within the CD8+ T cell subset. Interestingly, one patient showed modulation in TCRVbeta chain usage predominantly in the CD4+ T cell compartment. CONCLUSIONS: Modulation of TCRVbeta chain usage was detected in all patients analyzed. No clear-cut relation was observed between TCRVbeta modulation after transplantation and clinical outcome. In some cases modulations appeared to concur with observed immunological events (clinically and/or in-vitro).

HLA-DR Antigens↗

PubMed2000

Immunologic monitoring of the beneficial effect of one HLA-DR-shared blood transfusion in heart transplant patients.

BACKGROUND: Pre-transplant blood transfusion (BT) results in better graft survival in organ transplant recipients, especially when BT donor and allograft recipient share an HLA-DR antigen. Although the immunologic mechanisms involved are still poorly understood, we wanted to know whether down regulation of donor-reactive T cells play a role. METHODS: In a retrospective study, we analyzed the clinical effects of BT for 45 heart transplant (HTx) patients who had each received 1 BT that shared an HLA-DR-antigen with the recipient, and 55 who had a DR-mismatched BT before heart transplantation. From 30 patients, 15 with DR-shared BT and 15 with DR-mismatched BT, peripheral blood lymphocytes (PBL) were available. From each patient, we analyzed PBL samples taken at the day of transplantation (pre-transplant), and 1 to 2 months, 5 to 7 months, 9 to 14 months, 2 years, and 6 to 7 years after transplantation. Cytotoxic T-lymphocyte precursors (CTLp) and helper T-lymphocyte precursors (HTLp) were measured in a combined limiting dilution assay. RESULTS: Analysis of survival during the first 10 years revealed a significantly (p = 0.016) better survival rate in the group of patients who had received HLA-DR-shared BT compared with the group who had received HLA-DR-mismatched BT. Patients of the DR-shared group experienced significantly (p = 0.042) less acute rejections compared with the patients who received DR-mismatched BT. We found no differences in the development of graft vascular disease. Frequencies of CTLp specific for the organ donor did not change with time after transplantation in the individual patients, nor did we detect any differences between the two BT groups. We found the same for organ donor-specific HTLp frequencies. CONCLUSIONS: These data suggest again that transfusion effect depends on HLA-DR compatibility between the heart transplant recipient and the pre-transplant BT donor. The mechanism that caused better survival rate was not down regulation of the donor-reactive T-cell frequency.

Adult↗

PubMed2000

Variable leukocyte composition of red blood cell concentrates prepared in top-bottom systems: possible implications for pre-transplant blood transfusion.

BACKGROUND AND OBJECTIVES: The beneficial effect of blood transfusion on kidney graft survival requires the presence of leukocytes in the transfusate, but a minimal dose has not been defined, nor has the role of individual leukocyte subsets been investigated. In the Netherlands, a standard pre-transplant blood transfusion consists of a buffy coat (BC)-depleted red blood cell concentrate (RBCC) containing a maximum of 1.2x10(9) residual leukocytes per unit. However, leukocyte subset composition is not standardized. MATERIALS AND METHODS: Using FACS analysis, this study compared the residual leukocyte composition of RBCCs produced by Compomat((R)) and Optipress((R)), two currently used top-bottom systems. RESULTS: While the total leukocyte content of the RBCCs was equivalent in both press types (0.5x10(9)), the percentage of mononuclear cells (lymphocytes and monocytes) was significantly higher in the Compomat as compared with the Optipress system (p < 0. 0001), resulting in significantly higher numbers of transfused T cells, B cells, HLA-DR-positive cells, NK cells and stem cells. CONCLUSIONS: The leukocyte composition of a pre-transplant blood transfusion depends on the BC depletion method used; this might differentially affect the tolerizing or immunizing potential of a pre-transplant blood transfusion.

Blood Cell Count↗

PubMed1998

An alternative conditioning regimen for induction of specific skin graft tolerance across full major histocompatibility complex barriers.

Previously, we developed a well-tolerated single-day protocol for induction of stable multilineage chimerism and permanent donor-specific tolerance across major histocompatibility complex (MHC) barriers, with preservation of the host's normal immune responses. In our murine model, recipient mice were treated with a single dose of anti-CD3, anti-CD4, low dose total body irradiation (TBI; 3-6 Gy) and allogeneic bone marrow cells. An alternative cytoreductive strategy that is well-recognized in bone marrow transplantation, but has not been evaluated extensively in organ allograft recipients, involves the use of a combined chemotherapeutic drug treatment. The present data show that conditioning with low dose TBI, in a MHC-disparate donor-recipient combination, can be successfully substituted by a combined single low-dose dimethyl myleran (DMM)/cyclophosphamide (CY) therapy, resulting in both stable, mixed chimerism and specific skin graft tolerance.

Animals↗

PubMed1998

Haematopoietic stem cells can induce specific skin graft acceptance across full MHC barriers.

Previously, we and others have demonstrated in several animal models that the establishment of stable haematopoietic chimerism through allogeneic bone marrow transfusion provides an effective means for the development of specific transplantation tolerance. However, a major limitation to the clinical application of allogeneic bone marrow transfusion in immunosuppressed recipients for induction of tolerance to solid grafts, is the risk of graft-versus-host disease (GVHD). Therefore, it is important to identify the cell population needed for the induction of mixed chimerism and tolerance. Haematopoietic stem cells have the capacity of self-renewal and multilineage differentiation, and have been shown to reduce the risk of GVHD. We studied transfusion of two rich sources of stem cells, namely allogeneic fetal liver cells and a subset of purified bone marrow-derived progenitor cells (c-kit+) into anti-T cell monoclonal antibody-treated, low-dose irradiated recipient mice. Our data revealed that stable multilineage mixed chimerism and permanent donor-specific tolerance for skin, even when transplanted directly following conditioning, can be successfully achieved in this way, with no signs of GVHD.

Animals↗

PubMed1998

Long-term detection of microchimaerism in peripheral blood after pretransplantation blood transfusion.

Renal allograft survival is prolonged after pretransplantation blood transfusion. The aim of this study was to test retrospectively the development and persistence of microchimaerism after pretransplantation blood transfusion and to assess whether the type of blood transfusion (partially matched [= sharing of at least one HLA-B and one HLA-DR antigen between blood donor and recipient] versus mismatched) influences the (continued) presence of donor-type cells. A sensitive nested PCR technique based on HLA-DRB1 allele-specific amplification using sequence-specific primers (detection level: one donor cell among 10(5) recipient cells) for detection of donor cells was implemented in our laboratory. We studied 21 patients for microchimaerism in the peripheral blood compartment, following blood transfusion. Our preliminary data show that microchimaerism was detectable up to 8 weeks after blood transfusion. In all patients receiving a partially matched blood transfusion, donor-type cells were detected in the first week after transfusion, in 7/8 patients 2-4 weeks after transfusion, and in some patients up to 8 weeks after transfusion. After mismatched transfusion a tendency to shorter duration of microchimaerism was observed.

Blood Transfusion↗

PubMed1998

T cells discriminate between differentially phosphorylated forms of alphaB-crystallin, a major central nervous system myelin antigen.

Factors such as developmental stage or physiological and infectious stress may change patterns of post-translational protein modification. In order to determine whether such regulated types of modification may influence T cell responsiveness to self proteins we examined the T cell response of SJL (H-2s) mice to alphaB-crystallin, a small heat shock protein that can exist in differentially phosphorylated forms. Epitope mapping revealed the presence of two T cell epitopes that are presented by I-As. One major epitope including residues 41-56 contains an amino acid residue (Ser45) that can be phosphorylated as the result of aging or stress. Accordingly, T cells from SJL mice discriminate between preparations of alphaB-crystallin that differ in their extent of phosphorylation at the level of whole protein as well as at the level of determinant-specific responses. Phosphorylation at Ser45 does not prevent binding of the peptide 41-56 to I-As and computer-assisted modelling of the peptide-MHC complex suggests that the phosphate group of the bound peptide extends outwards from the peptide-binding cleft and may thus be available for direct contact with TCR. Together, our data provide evidence that stress-inducible phosphorylation of alphaB-crystallin creates neo-determinants for T cells and, therefore, may contribute to the breakdown of peripheral tolerance to this self protein.

Amino Acid Sequence↗

PubMed1998

Specific tolerance induction and organ transplantation.

Induction of tolerance to histocompatibility antigens of an organ donor would eliminate the need for long-term administration of nonspecific immunosuppressive drugs associated with an increased risk of infection and malignancies. Recently, we established a murine model in which recipient mice were treated with a single dose of anti-CD3, anti-CD4, low dose of total body irradiation (TBI) and allogeneic bone marrow cells. Our results clearly demonstrate that stable multilineage mixed chimerism, immunocompetence and permanent donor-specific skin graft tolerance across full major histocompatibility (MHC) barriers can be successfully achieved in this way. The observations that the preparative regimen and skin transplantation can be performed on the same day, and that a significant reduction in irradiation dose is sufficient in haploidentical donor-recipient combinations (MHC-sharing effect), bring our protocol closer to clinical use.

Animals↗

PubMed1997

Specific tolerance induction and transplantation: a single-day protocol.

Bone marrow transfusion is a well-established method for induction of mixed hematopoietic chimerism and donor-specific tolerance in animal models. This procedure, however, is inapplicable in clinical transplantation using cadaveric donors due to the interval (1 week to 7 months) between tolerance induction and organ transplantation. For clinical use, it is essential that allografts be placed at the time of bone marrow transfusion. In the present study, we performed skin transplantation within 1 hour after a nonlethal conditioning regimen. Recipient mice were treated with anti-CD3, anti-CD4, low-dose total body irradiation (3 to 6 Gy TBI) and fully mismatched or haploidentical donor bone marrow cells. Stable multilineage chimerism and specific T-cell nonresponsiveness developed. Donor skin grafts were permanently accepted. These results suggest that this single day protocol has clear potential for application in both cadaveric and living-related organ transplantation.

Animals↗

PubMed1997

The role of MHC class I heterodimer expression in mouse ankylosing enthesopathy.

Ankylosing enthesopathy (ANKENT) is a spontaneous mouse joint disease with strikingly similar pathology to human HLA-B27-associated enthesopathies such as ankylosing spondylitis. In C57Bl/10 mice, transgenic HLA-B*2702 as well as H2 genes have been shown to be relative risk factors for ANKENT. To investigate the role of major histocompatibility complex (MHC) class I expression in disease pathogenesis, ANKENT occurrence was compared among beta2-microglobulin (beta2m) knockout littermates with or without transgenes for HLA-B*2702 and human beta2m. In the knockout phenotype lacking beta2m, ANKENT occurrence is significantly reduced (P = 0.016). In the absence of beta2m, B*2702 is not detected on the cell membrane, nor does it increase the risk for ANKENT. This means that the previous finding that HLA-B*2702 increases susceptibility to ANKENT in C57Bl/10 mice cannot be ascribed to a transgene insertion effect. Rather, in order to increase disease susceptibility, B*2702 must be coexpressed with mouse beta2m (mo-beta2m). In contrast, when HLA-B*2702 is expressed with beta2m of human origin, disease susceptibility is not affected. Thus, both H2(b)-derived class I heterodimers and HLA-B*2702/mo-beta2m heterodimers contribute to ANKENT susceptibility.

Animals↗

PubMed1997

Role of spleen macrophages in innate and acquired immune responses against mouse hepatitis virus strain A59.

Owing to their scavenging and phagocytic functions, spleen macrophages are regarded to be important in the induction and maintenance of both innate and acquired immune defence mechanisms. In this study, we investigated the role of spleen macrophages in immunity against mouse hepatitis virus strain A59 (MHV-A59). Previous studies showed that spleen and liver macrophages are the first target cells for infection by MHV-A59 in vivo, suggesting that they could be involved in the induction of immune responses against MHV-A59. We used a macrophage depletion technique to deplete macrophages in vivo and studied the induction of virus-specific antibody and cytotoxic T-cell (CTL) responses and non-immune resistance against MHV-A59 in normal and macrophage-depleted mice. Virus titres in spleen and liver increased rapidly in macrophage-depleted mice, resulting in death of mice within 4 days after infection. Elimination of macrophages before immunization with MHV-A59 resulted in increased virus-specific humoral and T-cell proliferative responses. However, virus-specific CTL responses were not altered in macrophage-depleted mice. Our results show that spleen macrophages are of major importance as scavenger cells during MHV-A59 infection and are involved in clearance of virus from the host. In addition, macrophages may be involved in the regulation of acquired immune responses. In the absence of macrophages, increased virus-specific T-cell and antibody responses are detectable, suggesting that macrophages suppress MHV-A59-specific T- and B-cell responses and that other cells serve as antigen-presenting cells.

Animals↗

PubMed1996

Comparison of peptides eluted from the groove of HLA-B27 from Salmonella infected and non-infected cells.

Reactive arthritis (ReA) is associated with the MHC class-I molecule HLA-B27 and caused by certain Gram-negative bacteria. The mechanism by which HLA-B27 confers a higher susceptibility for this disease compared to other MHC Class-I alleles is still not known. We investigated whether infection of human HLA-B27+ cells is able to change the peptide repertoire presented by these HLA-B27 molecules. To this end large quantities of a B-cell line (C1R-B27) transfected with HLA-B2705 were infected with S. typhimurium. Peptides were eluted from the B27 molecules and separated by Reversed Phase Chromatography (RPC). We then compared the peptide profiles obtained from S. typhimurium infected CIR B-cells with that obtained from non infected cells. Apart from a few additional peaks present in the profile derived from the infected batch the peptide profiles were almost identical. A few fractions were subjected to sequencing by Edman degradation. All peptides found were nonameres with arginine (Arg) at position 2 which is in agreement with the previously described HLA-B27 peptide binding motif. The majority of peaks expressed a mixture of at least four different peptides. The analysis of differences between HLA-B27 bound peptides from Salmonella infected and non infected cells might lead to the identification of T-cell epitopes shared by Salmonella and autoantigens.

Arthritis, Reactive↗

PubMed1996

Immunization of HLA-B27 transgenic and non transgenic mice with Salmonella typhimurium results predominantly in the generation of proliferative T cell responses.

Reactive arthritis (ReA) due to Gram-negative intestinal bacteria or Chlamydia, is associated by an unknown mechanism with HLA-B27. Like other MHC class I molecules, HLA-B27 presents antigenic peptides derived from intracellular proteins to CD8+ cytotoxic T cells (CTL). In humans however, CTL specific for ReA associated bacteria have been reported in a limited number of studies. This may be caused by an inefficient in vivo induction of CTL against such micro-organisms. In the present study we addressed the question whether and to what extend mice transgenic for HLA-B27 are able to generate CTL against Salmonella typhimurium after immunization. To this end both HLA-B27 transgenic and non transgenic mice were immunized i.p., i.v. or orally, receiving a secondary challenge four weeks later. One day after infection with Salmonella, bacteria could be cultured from spleen and liver. There was no significant difference in the number of bacteria cultured from these organs between both groups of mice. Spleen cells from all immunized mice proliferated specifically in the presence of heat killed Salmonella but not in the presence of heat killed Yersinia. No proliferation of spleen cells from naive mice was observed in the presence of heat killed Salmonella, excluding the possibility that Salmonella antigens were mitogenic. Only in one out of 6 mice immunized i.v. with Salmonella Salmonella specific CTL could be generated. In order to rule out the possibility that in HLA-B27 transgenic mice the HLA-B27 molecule is not used as a restriction element by murine T cells, CTL were raised against the male minor histocompatibility (mH) antigen H-Y. Both murine class I as well as HLA-B27 restricted CTL could be generated. In conclusion this study demonstrates that MHC class I restricted CTL specific for the Gram-negative bacterium Salmonella typhimurium are difficult to generate in contrast to proliferative responses which can be easily demonstrated. This may comparable in humans where in the majority of studies bacteria specific T cells isolated from ReA patients appear to be CD4+ and class II restricted.

Animals↗

PubMed1996

A substantial level of mixed chimerism is required for the induction of permanent transplantation tolerance.

The induction of donor-specific transplantation tolerance is a major goal in organ transplantation, in order to eliminate the requirement for lifelong immunosuppressive therapy. Previously, we have developed a murine bone marrow transplantation model in which recipient mice were treated with a single dose of anti-CD3 and low dose whole body irradiation (WBI). Transfusion of donor bone marrow cells across a full H-2 disparity resulted in induction of high levels of stable mixed chimerism, specific T cell non-responsiveness and indefinite skin allograft survival. The present study has focused on manipulation of the level of chimerism in this model by varying the number of infused bone marrow cells, varying the dose of WBI and addition of syngeneic bone marrow cells. Our results indicate that a substantial level of chimerism is needed for induction of transplantation tolerance. In addition, in the semi-allogeneic donor-recipient combination an even lower dose of WBI was sufficient of engraftment of bone marrow cells and subsequent tolerance induction. We suggest that sharing of MHC antigens between donor and recipient might play an important role in facilitating the development of chimerism and tolerance in organ transplantation.

Animals↗

PubMed1996

Role of virus-specific CD4+ cytotoxic T cells in recovery from mouse hepatitis virus infection.

Macrophages and T lymphocytes play an important role in recovery from viral infections. During mouse hepatitis virus (MHV-A59) infection, a clear virus-specific class II-restricted cytotoxic T-cell response is generated. Transfer of these CD4+ cytotoxic T cells (CTL) into naive mice protects against a lethal challenge with MHV. However, their in vivo antiviral effector mechanism is not yet clear. To further investigate a possible effector mechanism, we studied the effect of adoptive transfer of CD4+ CTL on virus localization in spleen and liver. We showed that adoptive transfer of virus-specific T cells does not affect localization of MHV-A59 in different macrophage subsets. Interestingly, a rapid and large infiltrate of CD4+ T cells in and around MHV-A59-infected foci in the liver was observed early in infection, whereas no CD8+ T cells were detectable. Moreover, transfer of virus-specific T cells resulted in significantly decreased viral titres in the liver and spleen and a marginally increased anti-MHV-A59 IgM production. These results imply an important role for virus-specific CD4+ CTL in elimination of infectious MHV-A59 and induction of an effective immune response in the absence of CD8+ CTL.

Animals↗