Lack of H-2 gene influence on mouse susceptibility to secondary alveolar echinococcosis

To determine whether the development of hepatic Echinococcus multilocularis infection is influenced by major histocompatibility-linked genes, metacestode growth and host immune responses were compared in 4 C57BL/10 congenic murine strains of H-2b, H-2d, H-2k and H-2q haplotypes. Although the H-2q strain appeared slightly more resistant than the other strains, the 4 strains of mice developed comparable spleen cell proliferative response and Th1/Th2 cytokine production at 13 weeks p.i. A kinetic analysis, performed in 2 of these congenic strains, showed a similar pattern of parasite growth in these mice and failed to detect any significant difference in the production of parasite-specific IgM, IgG1 and IgG2, antibodies. Consequently, this study indicates that the control of secondary alveolar echinococcosis is not H-2 gene-linked.     

The T/B cell interaction involved in induction of the mouse IgG2ab suppression is restricted by major histocompatibility complex class I, but not class II molecules

To determine the major histocompatibility complex (MHC) restriction of the T/ B cell interaction involved in a negative regulation of Ig production, we used mouse model of T cell-induced IgG2ab suppression in vivo. Normal or specifically triggered T splenocytes from mice of the Igha haplotype, when neonatally transferred into histocompatible Igha/b heterozygotes, are able to induce a specific and total suppression of the IgG2ab allotype. Nevertheless, only transfer of IgG2ab-primed Igha T splenocytes induces this suppression in Ighb/b homozygous congenic mice in which the whole IgG2a isotype production is inhibited. This suppression is chronically maintained by CD8+ T cells, but can be experimentally reversed. We have established that the suppression induction required a CD4+CD8+ T cell cooperation and operated via the recognition by the involved TCR of C gamma 2ab-derived peptides presented by the target B cells in an MHC haplotype-restricted manner. Here, by using Ighb mice genetically deficient for MHC class I (beta 2-microglobulin%, or beta 2m%) or class II (I-A beta%) molecules, we demonstrate functionally that the suppression induction implicates an MHC class I-, but not class II-restricted interaction. Indeed, the anti-IgG2ab T cells transferred into Ighb H-2b I-A beta% mice carry out the suppression process normally, while in Ighb H-2b beta 2m% recipients, their suppression induction capacity is significantly inhibited. Moreover, the C gamma 2ab 103-118 peptide, identified as the sole C gamma 2ab-derived peptide able to amplify the anti-IgG2ab T cell reactivity in Igha H-2b mice, is also able to stabilize the H-2Db, but not the H-2Kb class I molecules at the surface of RMA-S (TAP2-, H-2b) cells. These results indicate that, despite the CD4+/CD8+ T cell cooperation during the induction phase of suppression only MHC class I molecule expression is required at the surface of IgG2ab+ B cells for suppression establishment.     

A nonimmunodominant nucleoprotein-derived peptide is presented by influenza A virus-infected H-2b cells

Influenza A virus-infected H-2b mice mount a CTL response directed against the nucleoprotein (NP) 366-374 but not against the NP 55-63 peptide, although both peptides fulfill the prerequisites for having high binding affinity toward the Db molecule. Two hypotheses have been proposed to explain the inability of B6 mice to respond to the NP 55-63 peptide: 1) B6 mice are tolerant to the NP 55-63 peptide and 2) NP 55-63 peptide is not naturally processed by H-2b cells. Our results show that 1) B6 mice possess a NP 55-63-specific CTL repertoire because their immunization with the NP 55-63 peptide itself recruits specific CTL; 2) NP 55-63 peptide is naturally processed by the virus-infected H-2b cells but its efficient presentation by the Db molecule requires higher amounts of NP than presentation of the NP 366-374 peptide; 3) NP 55-63 peptide is naturally presented in virus infected B6 mice, however, the quantity of Db/NP 55-63 complexes at the cell surface is sufficient to tolerize but not to recruit and stimulate specific CTL; and 4) NP 55-63 peptide binds to the Db molecule with a lower affinity than NP 366-374 does and this difference could explain the inefficient presentation of the NP 55-63 peptide by B6 cells. The involvement of the self-protein-derived nonimmunodominant peptides in self-tolerance and the possibility of using nonimmunodominant peptides of viral proteins for peptide vaccination are discussed.     

Solitary pancreas allografts. The role of percutaneous biopsy and standardized histologic grading of rejection

Murine models such as NZB/W F1, NZB.H-2bm12 and MRL.lpr/lpr mice have provided greater insight into the pathogenic mechanisms of lupus. To understand further the roles of T cells and cytokines in the pathogenesis of murine lupus, 11 cloned anti-DNA antibodies augmenting autoreactive T cell lines were derived from NZB/W F1 mice. All these autoreactive cells responded to syngeneic splenic cells and helped syngeneic B cells to produce anti-DNA antibodies, especially the IgG antibody. Ten out of 11 autoreactive T cell lines expressed neither CD4 nor CD8 cell surface markers on their surface. In addition, the cytokine production pattern of these autoreactive T cell lines was predominantly of type 0 (Th0) or type 2 T helper cells (Th2). To further investigate the role of accessory molecules in the activation of these autoreactive T cell lines, expression of IL-2R and heat-stable antigen (HSA) on these autoreactive T cells was analysed. Results suggest that the HSA played a critical role in the activation and function of these double-negative cloned autoreactive T cells.     

Interferon gamma-producing gammadelta T cell-dependent antibody isotype switching in the absence of germinal center formation during virus infection

Ig class switching usually occurs as a consequence of cognate interactions between antigen-specific B cells and CD4(+) alphabeta T cells. Vesicular stomatitis virus (VSV) infection of immunocompetent mice induces a rapid T-independent neutralizing IgM response followed by a long-lived T-dependent IgG response. Surprisingly, alphabeta T cell-deficient (TCRalpha-/-) mice also produced neutralizing IgG antibodies when infected with live VSV or with a recombinant vaccinia virus expressing the VSV glycoprotein (Vacc-IND-G), but not when immunized with UV-inactivated VSV (UV-VSV). The neutralizing IgG responses did not require the presence of NK cells or complement, but were crucially dependent on IFN-gamma and were predominantly of the IgG2a isotype. IgG production depended on residual CD3(+) non-alphabeta T cell populations present in the TCRalpha-/- mice, which produced IFN-gamma upon in vitro stimulation. A key role for gammadelta T cells was confirmed by the fact that TCRbeta-/- mice also generated strong neutralizing IgG responses to VSV, whereas TCRbeta-/-delta-/- mice produced very low titers. The neutralizing IgG responses of TCRalpha-/- mice were accompanied by the development of memory B cells, but not by antigen-specific germinal center (GC) formation. Thus, during viral infection of alphabeta T cell-deficient mice, gammadelta T cells may provide the signals that are required for isotype switching.     

Hematopoietic cells and radioresistant host elements influence natural killer cell differentiation

Radioresistant host elements mediate positive selection of developing thymocytes, whereas bone marrow-derived cells induce clonal deletion of T cells with receptors that are strongly autoreactive. In contrast to T cell development, little is known about the elements governing the natural killer (NK) cell repertoire, which, similar to the T cell repertoire, differs between individuals bearing different major histocompatibility complex (MHC) phenotypes. We have used murine bone marrow transplantation models to analyze the influence of donor and host MHC on an NK cell subset. We examined the expression of Ly-49, which is strongly expressed on a subpopulation of NK cells of H-2b mice, but not by NK cells of H-2a mice, probably because of a negative effect induced by the interaction of Ly-49 with Dd. To evaluate the effect of hematopoietic cell H-2a expression on Ly-49 expression of H-2b NK cells, we prepared mixed allogeneic chimeras by administering T cell-depleted allogeneic (B10.A, H-2a) and host-type (B10, H-2b) marrow to lethally irradiated B10 mice, or by administering B10. A marrow to B10 recipients conditioned by a nonmyeloablative regimen. Expression of H-2a on bone marrow-derived cells was sufficient to downregulate Ly-49 expression on both H-2a and H-2b NK cells. This downregulation was thymus independent. To examine the effect of H-2a expressed only on radioresistant host elements, we prepared fully allogeneic chimeras by administering B10 bone marrow to lethally irradiated B10.A recipients. B10 NK cells of these fully allogeneic chimeras also showed downregulation of Ly-49 expression. The lower level of H-2a expressed on H-2b x H-2a F1 cells induced more marked downregulation of Ly-49 expression on B10 NK cells when presented on donor marrow in mixed chimeras than when expressed only on radioresistant host cells. Our studies show that differentiation of NK cells is determined by interactions with MHC molecules expressed on bone marrow-derived cells and, to a lesser extent, by MHC antigens expressed on radioresistant host elements.     

CD28-independent induction of T helper cells and immunoglobulin class switches requires costimulation by the heat-stable antigen

It is well established that B7-CD28/CTLA4 interactions play an important role in the induction of T helper cells for T-dependent antibody responses. However, targeted mutation of CD28 does not significantly affect production of IgG and activation of CD4 T helper cells in response to infections by some viruses and nematode parasites. To test whether the CD28-independent induction of Ig class switches requires costimulation by the heat-stable antigen (HSA), we compared T helper cell induction and antibody response in mice deficient for either HSA, CD28, or both genes. We found that after immunization with KLH-DNP, mice deficient for both CD28 and HSA lack DNP-specific IgA and all subtypes of IgG. This deficiency corresponds to a reduced number of effector helper T cells that rapidly produce IL-2, IL-4, and IFN-gamma after in vitro stimulation with carrier antigen KLH. In contrast, priming of T helper cells and Ig class switch are normal in mice deficient with either HSA or CD28 alone. IgM responses are not affected by any of these targeted mutations. These results demonstrate that CD28-independent induction of T helper cells and Ig class-switches requires costimulation by the HSA.     

Th1 response in Salmonella typhimurium-infected mice with a high or low rate of bacterial clearance

Previous studies have shown that the capacity to clear an attenuated strain of Salmonella typhimurium after the second week of infection varies widely among mouse strains. Bacterial clearance is mediated by CD4+ T cells and is regulated in part by the H-2 complex. The aim of the present study was to compare the patterns of cytokine mRNA expression in the spleens of C57BL/6 (H-2b) and CBA (H-2k) mice, which exhibit a low and a high rate of bacterial clearance, respectively. A transient increase in interleukin-12 (IL-12) mRNA levels was found in both mouse strains. Gamma interferon (IFN-gamma) gene expression was higher and more sustained in C57BL/6 than in CBA mice. No increase in IL-4 mRNA was detected. A transient increase in IL-10 mRNA was found in C57BL/6 mice. Separation of spleen cells into CD4+ and CD4- fractions showed that CD4+ T cells produced the bulk of IFN-gamma in both mouse strains and of IL-10 in C57BL/6 mice. Infection of H-2 congenic mice induced a higher level of IFN-gamma mRNA expression by CD4+ T cells in mice with a low rate of clearance (H-2b) than in mice with a high rate of clearance (H-2q). Treatment of infected C57BL/6 mice with anti-IFN-gamma or anti-CD4 monoclonal antibodies indicated that IFN-gamma participates in resistance in the early phase of infection, but not in bacterial clearance, and that CD4+ T cells mediate bacterial clearance during the 3rd week of infection. Taken together, these results suggest that defective bacterial clearance in H-2b mice is not linked to defective IFN-gamma production and that CD4+ T cells mediate bacterial clearance by an IFN-gamma-independent mechanism.     

Lethal murine graft-versus-host disease induced by donor gamma/delta expressing T cells with specificity for host nonclassical major histocompatibility complex class Ib antigens

Although T-cell receptor (TCR) alpha/beta expressing cells have a well-known role in graft-versus-host disease (GVHD) generation, the role of TCR gamma/delta expressing cells in this process has remained unclear. To elucidate the potential function of TCR gamma/delta cells in GVHD, we have used transgenic (Tg) H-2d mice (termed G8) that express gamma/delta heterodimers on a high proportion of peripheral T cells. In vitro, G8 Tg gamma/delta T cells proliferate to and kill C57BL/6 (B6) (H-2b) which express gene products (T10b and T22b) from the nonclassical major histocompatibility complex (MHC) class Ib H-2T region. The infusion of G8 Tg (H-2Td) TCR gamma/delta cells into lethally irradiated [900 cGy total body irradiation (TBI)] B6 (H-2b) mice resulted in the generation of lethal GVHD characterized histologically by destruction of the spleen, liver, lung, and colon. Lethal GVHD was prevented by the injection of anti-TCR gamma/delta monoclonal antibodies. Immunohistochemical analysis of B6 recipients post-bone marrow transplantation (BMT) confirmed that G8 Tg TCR gamma/delta cells infiltrated GVHD target tissues (skin, liver, colon, and lung) and were absent in recipients treated with anti-TCR gamma/delta monoclonal antibodies (MoAbs) but not anti-CD4 plus anti-CD8 MoAbs. In contrast, injection of TCR gamma/delta+ cells into irradiated (900 cGy TBI) B6.A-TIaa BoyEg mice that do not express either T10b or T22b did not induce lethal GVHD. Similarly, in a different GVHD system in which sublethal irradiation without bone marrow (BM) rescue was used, B6 but not B6.A-TIaa/BoyEg mice were found to be susceptible to TCR gamma delta+ cell mediated GVHD-induced lethality characterized by an aplasia syndrome. These results demonstrate that TCR gamma/delta cells have the capacity to cause acute lethal GVHD in mice and suggest that nonclassical MHC class Ib gene products expressed on GVHD target organs are responsible for G8 Tg TCR gamma/delta+ cell mediated lethality.     

Antibody response of murine B1 cells to hen eggwhite lysozyme

Cell transfer studies were performed to investigate the ability of murine peritoneal B1 cells to produce specific IgG antibody against the T-dependent protein antigen, hen eggwhite lysozyme (HEL). Peritoneal cells (PeC) from normal BALB/c mice were transferred into newborn, allotype-congenic, C.B-17 severe combined immunodeficient (SCID) mice alone or together with splenic T cells from HEL-primed C.B-17 mice. After immunization with HEL, only those mice that received both PeC and primed T cells produced HEL-specific IgG of the PeC donor allotype. To identify the B cell subset responsible for antibody production, PeC were sorted before transfer into B1 and conventional B (B2) cell populations. It was found that transfer of purified B1 cells plus primed T cells resulted in high levels of IgG1 anti-HEL in approximately half of the SCID recipients, while mice receiving B2 cells produced little detectable antibody. The responses consisted primarily of IgG1 kappa anti-HEL, with no significant IgM or lambda-bearing components. Seventeen HEL-specific hybridomas of BALB/c origin, i.e., derived from the B1 cell donor, were obtained from reconstituted SCID mice after various periods of immunization and analyzed for fine specificity using a panel of avian lysozymes. All but one of the B1 cell-derived mAbs recognized an HEL epitope not present on the closely related bobwhite quail lysozyme (differing from HEL at only 4 of 129 amino acid positions). While IEF analyses demonstrated the presence of extensive clonotypic diversity, the epitope specificity pattern, which is rare among B2-cell-derived antibodies, suggests that the B1 cell recognition repertoire for HEL is severely limited.     

A novel antagonist, phenylbenzene omega-phosphono-alpha-amino acid, for strychnine-sensitive glycine receptors in the rat spinal cord

Leukaemia-specific proteins may be recognized by T-lymphocytes as neoantigens if peptides corresponding to mutated sequences bind to major histocompatibility complex (MHC) molecules on leukaemic cells. We studied the ability of a series of synthetic peptides corresponding to the junctional sequences of BCR/ABL proteins to bind to class I molecules in two human cell lines, LBL 721.174 (T2) (HLA-A2, B5) and BM36.1 (HLA-A1, B35), and one murine cell line RMA-S (H-2Kb, Db). These cell lines are defective in intracellular peptide loading of class I molecules, resulting in markedly reduced cell surface class I expression: class I expression can be rescued by provision of peptides binding to the alleles expressed by the mutant cell. Eighteen peptides spanning the junctional sequences of the b2a2 and b3a2 proteins were tested for their ability to rescue expression of the class I alleles borne by these cells using flow cytometry. Allele-specific control peptides known to bind HLA-A2, HLA-B35, H-2Kb and H-2Db increased expression of these alleles 2- to 3-fold: 0/18 BCR/ABL peptides enhanced HLA-A2, HLA-B35 or H-2Kb expression, but three b2a2 peptides consistently increased H-2Db expression. These results suggest that BCR/ABL junctional peptides are unlikely to be presented to T-cells in association with HLA-A2, HLA-B35 or H-2Kb. Conversely, the finding that some b2a2 peptides bind specifically to H-2Db suggests that a murine model of graft-versus-leukaemia (GVL) could be constructed.     

Reduced susceptibility to collagen-induced arthritis in mice deficient in IFN-gamma receptor

Collagen-induced arthritis (CIA) is an arthritic model that was developed after immunization with type II collagen (CII). Apparently, contradictory results have been reported regarding the role of IFN-gamma in the development of CIA. Therefore, we employed IFN-gamma R-deficient mice to study the role of IFN-gamma. To introduce the CIA susceptibility gene (H-2q), IFN-gamma R-deficient (H-2b/b/IFN-gamma R-/-) mice were mated with DBA/1 (H-2q/q/IFN-gamma R+/+) mice; next, the F1 mice were interbred to yield F2 offspring bearing different combinations of H-2 (H-2q/q, H-2q/b, and H-2b/b) and IFN-gamma R (IFN-gamma R+/+, IFN-gamma R+/-, and IFN-gamma R-/-) genes. Although the H-2q allele appeared to confer susceptibility to CIA, mice that were homozygous for the IFN-gamma R mutation showed a substantially decreased incidence and severity of CIA. The CII-specific IgG levels of serum samples, which are known to be involved in the development of CIA, were remarkably reduced in IFN-gamma R-/- mice. Furthermore, the anti-CII IgG2a levels controlled by IFN-gamma R were significantly reduced in IFN-gamma R-/- F2 mice compared with those seen in IFN-gamma R+/+ and IFN-gamma R+/- mice, although the levels of all IgG subclass Abs examined were lower in IFN-gamma R-/- mice than in IFN-gamma R+/+ mice. No clear evidence of the imbalance of Th1/Th2 cytokines was observed in CII-immunized, IFN-gamma R-deficient mice. Taken together, these results suggest that IFN-gamma exacerbates CIA by affecting, at least, levels of CII-specific IgG Ab rather than the imbalance of Th1/Th2 cells.     

Murine gamma/delta-expressing T cells affect alloengraftment via the recognition of nonclassical major histocompatibility complex class Ib antigens

T cells with antidonor specificities have been isolated from human recipients experiencing graft rejection after allogeneic bone marrow transplantation (BMT). Partial T-cell depletion of unrelated BM grafts with an anti- T-cell receptor (TCR) monoclonal antibody (MoAb) directed against the TCR alpha/beta heterodimer have shown that the incidence of graft-versus-host disease is low and that the incidence of durable engraftment is high. These studies suggest either that the number of residual TCR alpha/beta+ cells was sufficient to permit alloengraftment or that the preservation of cells other than TCR alpha/beta+ cells was beneficial for engraftment. With respect to the latter, one such candidate cell is the TCR gamma/delta+ T cell. Because no studies have specifically examined whether TCR gamma/delta+ cells might be capable of eliminating BM-derived hematopoietic cells, we established a new graft rejection model system in which transgenic (Tg) H-2d mice (termed G8), known to express gamma/delta heterodimers on high proportion of peripheral T cells, were used as BMT recipients. These Tg TCR gamma/delta+ cells respond vigorously to target cells that express the nonclassical major histocompatibility complex (MHC) class lb region gene products encoded in H-2T region of H-2T(b)+ strains. G8 Tg mice were used as recipients for C57BL/6 (B6: H-2(b); H-2T(b)) T-cell-depleted (TCD) donor BM. We show that G8 Tg (H-2(d), H-2T(d)) mice are potent mediators of B6 BM graft rejection and that the rejection process was inhibited by anti-TCR gamma/delta MoAbs. In contrast, BM from a B6 congenic strain that expresses the H-2T(a) allele, B6.A-Tl(a)/BoyEg, was readily accepted, suggesting that H-2T antigens on repopulating donor BM cells are the targets of host graft rejecting T cells that express the TCR gamma/delta heterodimer. PB chimerism studies were performed at > or = 1.5 months post-BMT using TCD BM from severe combined immunodeficient allogeneic donors, which is highly susceptible to rejection by the host. The addition of donor G8 TCR gamma/delta+ cells to TCD donor BM was shown to significantly increase alloengraftment in B6 recipients. These results show that (1) host TCR gamma/delta+ cells can reject repopulating donor cells, presumably by responding to nonclassical MHC class lb gene products expressed on BM-derived hematopoietic progenitor cells; and (2) donor TCR gamma/delta+ cells can facilitate the alloengraftment of rigorously TCD donor BM.     

Autoimmunity caused by disruption of central T cell tolerance. A murine model of drug-induced lupus

A side effect of therapy with procainamide and numerous other medications is a lupus-like syndrome characterized by autoantibodies directed against denatured DNA and the (H2A-H2B)-DNA subunit of chromatin. We tested the possibility that an effect of lupus-inducing drugs on central T cell tolerance underlies these phenomena. Two intrathymic injections of procainamide-hydroxylamine (PAHA), a reactive metabolite of procainamide, resulted in prompt production of IgM antidenatured DNA antibodies in C57BL/6xDBA/2 F1 mice. Subsequently, IgG antichromatin antibodies began to appear in the serum 3 wk after the second injection and were sustained for several months. Specificity, inhibition and blocking studies demonstrated that the PAHA-induced antibodies showed remarkable specificity to the (H2A-H2B)-DNA complex. No evidence for polyclonal B cell activation could be detected based on enumeration of Ig-secreting B cells and serum Ig levels, suggesting that a clonally restricted autoimmune response was induced by intrathymic PAHA. The IgG isotype of the antichromatin antibodies indicated involvement of T cell help, and proliferative responses of splenocytes to oligonucleosomes increased up to 100-fold. As little as 5 microM PAHA led to a 10-fold T cell proliferative response to chromatin in short term organ culture of neonatal thymi. We suggest that PAHA interferes with self-tolerance mechanisms accompanying T cell maturation in the thymus, resulting in the emergence of chromatin-reactive T cells followed by humoral autoimmunity.     

Isotype profiles of Leishmania donovani-infected BALB/c mice: preferential stimulation of IgG2a/b by liposome-associated promastigote antigens

Leishmaniasis presents a complex spectrum of diseases and immunological manifestations depending upon both the species of the microorganism and the host it infects. BALB/c mice, which are homozygous for Lsh(s) on chromosome 1, are genetically susceptible to the visceralizing species of Leishmania. Infection of these mice with an Indian strain of Leishmania donovani showed a steady rise in the level of parasite burden in both the liver and the spleen to 24 wk. To investigate the immune responses determining the course of infection, we studied the relative levels of specific IgG, IgM, and IgA antibodies, and IgG isotypes, in the sera of diseased and protectively immunized mice at different periods of infection. IgG1 and IgG2a were stimulated in the control, infected, and immunized mice after parasite challenge. However, an early induction of IgG1 in the normal infected mice and stimulation of IgG2a and IgG2b isotypes prior to parasite challenge in liposome-antigen-immunized mice suggest that the elicitation of a particular subset of CD4+ T cells at the onset of disease may be responsible for either progression or resolution of infection.     

Induction of specific T cell tolerance by Fas ligand-expressing antigen-presenting cells

Autocrine interaction of Fas and Fas ligand leads to apoptosis of activated T cells, a process that is critical for the maintenance of peripheral T cell tolerance. Paracrine interactions of Fas ligand with T cells also may play an important role in the maintenance of tolerance, as Fas ligand can create immune-privileged sites and prevent graft rejection by inducing apoptosis in T cells. We surmised that APCs that express Fas ligand might directly induce apoptosis of T cells during presentation of Ag to the T cells, thus inducing Ag-specific, systemic T cell tolerance. Here, we show that profound, specific T cell unresponsiveness to alloantigen was induced by treatment of H-2k mice with H-2b APCs that expressed Fas ligand and that profound T cell unresponsiveness specific for the H-Y Ag was induced by treatment of H-2Db/H-Y TCR transgenic female mice with H-2Db/H-Y APCs that expressed Fas ligand. The induction of this systemic T cell tolerance required the expression of Fas ligand on the APCs as well as the expression of Fas on the T cells. The tolerance was restricted to the Ag presented by the APCs. The rapid and profound clonal deletion of the Ag-specific, peripheral T cells mediated by the Fas ligand-expressing APCs contributed to the induction of tolerance. These findings demonstrate that Ag-specific T cell tolerance can be induced by APCs that express Fas ligand and suggest a novel function for APCs in the induction of T cell apoptosis. Furthermore, they indicate a novel immunointervention strategy for treatment of graft rejection and autoantigen-specific autoimmune diseases.     

Susceptibility to anti-glomerular basement membrane disease and Goodpasture syndrome is linked to MHC class II genes and the emergence of T cell-mediated immunity in mice

We developed a new mouse model of human anti-glomerular basement membrane (GBM) disease to better characterize the genetic determinants of cell-mediated injury. While all major histocompatibility complex (MHC) haplotypes (H-2a, k, s, b, and d) immunized with alpha3 NC1 domains of type IV collagen produce anti-alpha3(IV) NC1 antibodies that cross-react with human Goodpasture [anti-GBM/anti-alpha3(IV) NC1] autoantibodies, only a few strains developed nephritis and lung hemorrhage associated with Goodpasture syndrome. Crescentic glomerulonephritis and lung hemorrhage were MHC-restricted in haplotypes H-2s, b, and d (A beta/A alpha region in H-2s) and associated with the emergence of an IL-12/Th1-like T cell phenotype. Lymphocytes or anti-alpha3(IV) NC1 antibodies from nephritogenic strains transfer disease to syngeneic recipients. However, passive transfer of isogenic alpha3(IV) NC1 antibodies into -/- T cell receptor-deficient mice failed to produce nephritis. Finally, nephritis and its associated IL-12/Th1-like T cell response attenuate in disease-susceptible mice tolerized orally to alpha3(IV) collagen before immunization. Our findings suggest collectively, as a hypothesis, that anti-GBM antibodies in mice only facilitate disease in MHC haplotypes capable of generating nephritogenic lymphocytes with special T cell repertoires.     

Influence of adjuvants on the induction of autoantibodies to the thyrotropin receptor

To determine the influence of adjuvant on the induction of antibodies to thyrotropin receptor (TSHR), we immunized BALB/c mice with a extracellular domain of the TSHR (ETSHR) protein in complete Freund's adjuvant (CFA), Titer Max (TM) and Gerbu. Similarly, control groups of mice were immunized with bovine serum albumin (BSA) in each of the different adjuvants. As determined by ELISA, ETSHR given along with CFA elicited high titers of antibodies to ETSHR which were mainly restricted to the IgG1 subclass. Mice immunized with ETSHR in TM also developed high titers of anti-ETSHR antibodies but had higher levels of both IgG1 and IgG2a. However, immunization with ETSHR in Gerbu resulted in low titers of antibodies, restricted to IgG1 subclass. Immunization of mice with BSA in each of the three adjuvants induced higher antibody titers to BSA. The subclass of antibodies in mice immunized with BSA in CFA and TM were predominantly IgG1 and IgG2a with lower levels of IgG2b, whereas in Gerbu treated group, antibody to BSA was restricted to IgG1 subclass. Analysis of specificity of antibodies against ETSHR, in mice immunized with ETSHR, revealed that irrespective of the adjuvant used, the dominant reactivity was against peptide 1 (AA 22-41) with weaker reactivity against several other. peptides. The only exception was in mice immunized with ETSHR in TM which also showed significant reactivity against peptide 23 (AA 352-371). Mice immunized with the ETSHR in CFA or in TM showed elevated levels of serum TSH binding inhibitory immunoglobulins (TBII). However, mice immunized with ETSHR in Gerbu, which had lower titers of antibodies to ETSHR, showed normal TBII levels. These studies showed that adjuvant composition could influence the titer, subclass and fine specificity of antibodies to ETSHR which in turn could affect the development of TBII activity.     

Efficient tumor eradication by adoptively transferred cytotoxic T-cell clones in allogeneic hosts

Tumor-specific cytotoxic T cells (CTLs) can play an important role against cancer as illustrated by the observation that adoptive transfer of tumor-specific CTLs can mediate potent anti-tumor effects. Although such CTLs can be detected at the tumor site, relatively little is known about the mechanisms by which they enter the tumor. In this study, the role of major histocompatibility complex (MHC) class 1 molecules on vascular endothelium in the tumor in entry of, and tumor eradication by, tumor-specific CTL was investigated. Two H-2Db-restricted CTL clones recognizing peptide VNIRNCCYI on human adenovirus type 5 early region 1-(Ad5E1)-induced tumors were used to test whether CTLs were able to cross the vascular endothelium lacking the restricting MHC molecule. One CTL clone recognizes peptide VNIRNCCYI in the context of both H-2Db and H-2Dbm14 molecules. The other CTL clone recognizes this peptide only in the context of H-2Db. Adoptive transfer of these CTLs leads to eradication of Ad5E 1-induced, H-2Db-expressing tumors in B6(H-2Db+) and Bm14(H-2Db-) nude mice. Our data show that presentation of tumor-derived peptides by MHC molecules on endothelial cells of blood vessels in a tumor do not play a major role in eradication of tumors by adoptively transferred CTL in combination with interleukin-2. Moreover, our data show that successful adoptive CTL immunotherapy is possible across allogeneic barriers, without inducing severe side effects, provided the tumor expresses the MHC class 1-peptide complex recognized by the CTLs.     

Induction and exhaustion of lymphocytic choriomeningitis virus-specific cytotoxic T lymphocytes visualized using soluble tetrameric major histocompatibility complex class I-peptide complexes

This study describes the construction of soluble major histocompatibility complexes consisting of the mouse class I molecule, H-2Db, chemically biotinylated beta2 microglobulin and a peptide epitope derived from the glycoprotein (GP; amino acids 33-41) of lymphocytic choriomeningitis virus (LCMV). Tetrameric class I complexes, which were produced by mixing the class I complexes with phycoerythrin-labeled neutravidin, permitted direct analysis of virus-specific cytotoxic T lymphocytes (CTLs) by flow cytometry. This technique was validated by (a) staining CD8+ cells in the spleens of transgenic mice that express a T cell receptor (TCR) specific for H-2Db in association with peptide GP33-41, and (b) by staining virus-specific CTLs in the cerebrospinal fluid of C57BL/6 (B6) mice that had been infected intracranially with LCMV-DOCILE. Staining of spleen cells isolated from B6 mice revealed that up to 40% of CD8(+) T cells were GP33 tetramer+ during the initial phase of LCMV infection. In contrast, GP33 tetramers did not stain CD8+ T cells isolated from the spleens of B6 mice that had been infected 2 mo previously with LCMV above the background levels found in naive mice. The fate of virus-specific CTLs was analyzed during the acute phase of infection in mice challenged both intracranially and intravenously with a high or low dose of LCMV-DOCILE. The results of the study show that the outcome of infection by LCMV is determined by antigen load alone. Furthermore, the data indicate that deletion of virus-specific CTLs in the presence of excessive antigen is preceded by TCR downregulation and is dependent upon perforin.