Peptide-specific prevention of experimental allergic encephalomyelitis. Neonatal tolerance induced to the dominant T cell determinant of myelin basic protein.

Experimental allergic encephalomyelitis (EAE) is a model of antigen-specific T cell-mediated autoimmune disease. The alpha-acetylated, NH2-terminal nine amino acids (1-9NAc) of myelin basic protein (MBP) represents the dominant T cell epitope for the induction of EAE in the B10.PL (H-2u) strain. We tolerized neonatal B10.PL mice to 1-9NAc and studied the proliferative responses to this peptide and to whole MBP. Mice exposed to 1-9NAc in the neonatal period were tolerant to subsequent challenge at the proliferative T cell level. Similarly, in the 1-9NAc-tolerant group, both the incidence and severity of 1-9NAc induced EAE were greatly reduced. The fact that we were able to tolerize mice normally responsive to MBP suggests that this self antigen is sequestered (within the central nervous system) and hence tolerance to it is not normally induced. No significant difference in disease incidence was seen in response to rat MBP between control animals and 1-9NAc-tolerized mice (50% in both groups), demonstrating the presence of at least one additional encephalitogenic determinant elsewhere on the molecule. We have successfully prevented disease induction by peptide-induced tolerization. Tolerance induction by peptides provides a new and specific strategy in the prevention of autoimmunity. However, it will be clearly necessary to fully define all epitopes potentially capable of inducing pathogenic T cells to ensure complete and effective therapy of T cell-mediated autoimmune disease.

Two minor determinants of myelin basic protein induce experimental allergic encephalomyelitis in SJL/J mice.

Experimental allergic encephalomyelitis (EAE) is an autoimmune demyelinating disease of the central nervous system (CNS) that occurs after immunization of animals with myelin basic protein (MBP). The disease is a prototype model for the study of antigen-specific T helper cell-mediated autoimmune disease. In SJL/J mice, EAE is mediated by T helper cells directed against a 40-amino acid COOH-terminal peptic fragment of mouse small MBP. To identify the minimal T cell epitopes of MBP responsible for EAE, overlapping peptides completely encompassing the epitopes within this region were synthesized. A 28-residue peptide of mouse MBP spanning residues 87-114 (pM87-114) was able to elicit both a strong T cell response and chronic relapsing disease. To better localize the T cell epitopes, shorter peptides within this region were synthesized and two overlapping peptides, pM87-98 and pM91-104, were able to induce EAE. T cell clones and bulk lymph node cell populations reactive with pM87-98 did not respond to pM91-104. However, lymph node cells reactive with pM91-104 also reacted with pM87-98, thus showing that these two peptides represent contiguous, but distinct encephalitogenic epitopes and that both these epitopes may be contained within pM87-98. In addition, pM87-114 and pM87-98 were found to be minor determinants of the total T cell response to rat and rabbit MBP. The restricted response to MBP in SJL/J mice is similar to that of the PL/J mice in that each appears to have only a single peptide region in MBP that elicits encephalitogenic T cells. However, within the region studied, there were two if not more T cell epitopes. This differs from the single encephalitogenic PL/J epitope. These findings of a single encephalitogenic peptide region with multiple T cell epitopes and the fact that encephalitogenic T cell epitopes may be subdominant have implications for the design of treatments directed at the T cell receptor-MHC-peptide epitope complex in autoimmune disease.

Induction of immunity to prostate cancer antigens: results of a clinical trial of vaccination with irradiated autologous prostate tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor using ex vivo gene transfer.

Vaccination with irradiated granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting gene-transduced cancer vaccines induces tumoricidal immune responses. In a Phase I human gene therapy trial, eight immunocompetent prostate cancer (PCA) patients were treated with autologous, GM-CSF-secreting, irradiated tumor vaccines prepared from ex vivo retroviral transduction of surgically harvested cells. Expansion of primary cultures of autologous vaccine cells was successful to meet trial specifications in 8 of 11 cases (73%); the yields of the primary culture cell limited the number of courses of vaccination. Side effects were pruritus, erythema, and swelling at vaccination sites. Vaccine site biopsies manifested infiltrates of dendritic cells and macrophages among prostate tumor vaccine cells. Vaccination activated new T-cell and B-cell immune responses against PCA antigens. T-cell responses, evaluated by assessing delayed-type hypersensitivity (DTH) reactions against untransduced autologous tumor cells, were evident in two of eight patients before vaccination and in seven of eight patients after treatment. Reactive DTH site biopsies manifested infiltrates of effector cells consisting of CD45RO+ T-cells, and degranulating eosinophils consistent with activation of both Th1 and Th2 T-cell responses. A distinctive eosinophilic vasculitis was evident near autologous tumor cells at vaccine sites, and at DTH sites. B-cell responses were also induced. Sera from three of eight vaccinated men contained new antibodies recognizing polypeptides of 26, 31, and 150 kDa in protein extracts from prostate cells. The 150-kDa polypeptide was expressed by LNCaP and PC-3 PCA cells, as well as by normal prostate epithelial cells, but not by prostate stromal cells. No antibodies against prostate-specific antigen were detected. These data suggest that both T-cell and B-cell immune responses to human PCA can be generated by treatment with irradiated, GM-CSF gene-transduced PCA vaccines.

Clinical significance of a single test for anti-cardiolipin antibodies in patients with systemic lupus erythematosus.

PURPOSE: Clinicians have difficulty interpreting results of tests for anti-cardiolipin antibodies (aCL) because of conflicting reports of the clinical associations of these antibodies in patients with systemic lupus erythematosus (SLE). We therefore decided to evaluate the clinical associations of aCL in an effort to facilitate interpretation of single reports of either positive or negative test results. We also assessed the role of estrogen on the development of aCL. PATIENTS AND METHODS: The study population consisted of 85 consecutive outpatients with SLE and 40 control subjects. Serum samples and clinical and laboratory data were obtained from each patient and control. Testing for aCL was performed using a standardized enzyme-linked immunoabsorbent assay developed at an international workshop. RESULTS: The presence of aCL was documented in 42.4 percent of patients with SLE and 7.5 percent of control subjects. In patients with SLE, these antibodies were significantly associated with thrombosis, fetal loss, and thrombocytopenia, but not with other manifestations. Measurement of all isotypes optimized clinical correlations. Titers did not add clinical utility. Fluctuations of levels of aCL occurred, making it difficult to interpret a single negative result. Among control subjects, the presence of aCL was not significantly more common in women who used oral contraceptives. CONCLUSION: Our findings suggest that positive results of testing for aCL correlate with a predisposition for thrombosis, fetal loss, and thrombocytopenia in patients with SLE; however, the test is not predictive for other clinical manifestations of SLE, including activity and severity of disease. We believe that measurement of all isotypes of aCL should be performed in patients with SLE considering pregnancy, to identify those with a high risk of fetal loss, and in SLE patients with a thrombotic episode.

Cancer cells engineered to secrete granulocyte-macrophage colony-stimulating factor using ex vivo gene transfer as vaccines for the treatment of genitourinary malignancies.

When irradiated and administered intradermally as vaccines, cancer cells engineered to secrete high levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) by gene transfer elicit potent anticancer immune responses in a variety of animal tumor models. Upon vaccination, antigens present in the cancer cells are phagocytosed and processed by skin dendritic cells. These dendritic cells then prime anticancer immune responses by presenting antigenic peptides to T cells. The immune responses generated are capable of eradicating small but lethal cancer cell inocula with minimal toxicity in preclinical animal tumor studies. To develop this vaccination strategy for the treatment of human genitourinary cancers, we have conducted phase I clinical trials using human genitourinary cancer cells as sources of cancer cell antigens. In the first human clinical trial of genetically engineered cancer cell vaccines, a phase I clinical trial of kidney cancer cell vaccines (n = 18), kidney cancer cells were removed at surgery, propagated briefly in vitro, and then genetically modified to secrete high levels of GM-CSF via ex vivo transduction with the retrovirus MFG-GM-CSF. After irradiation, the kidney cancer cells were administered as vaccines to 18 patients with advanced kidney cancers. Vaccine treatment, which caused few side effects, nonetheless appeared to trigger anticancer immune responses manifest as conversion of delayed-type hypersensitivity (DTH) skin responses against irradiated autologous cancer cells after vaccination. Biopsies of vaccine sites yielded findings reminiscent of biopsies from preclinical animal model studies, with evidence of vaccine cell recruitment of dendritic cells, T cells, and eosinophils. One patient with measurable kidney cancer metastases treated at the highest vaccine dose level experienced a partial treatment response. The bioactivity of GM-CSF-secreting autologous cancer cell vaccines was confirmed in a phase I clinical trial for prostate cancer (n = 8). Vaccine cells were prepared from surgically harvested prostate tumors by ex vivo transduction with MFG-GM-CSF in a manner similar to that used for the kidney cancer trial. Vaccine treatment was well tolerated and associated with induction of anticancer immunity as assessed using DTH skin testing. In addition, new antiprostate cancer cell antibodies were detected in serum samples from treated men as a consequence of vaccination. These first clinical trials of GM-CSF-secreting cancer cell vaccines for the treatment of genitourinary cancers have demonstrated both safety and bioactivity, in that very few side effects have been seen and anticancer immune responses have been detected. Future clinical studies will be required to assess vaccine treatment efficacy, refine vaccination dose and schedule, define the appropriate clinical context for the use of such vaccines, and ascertain optimal combinations involving vaccines and other local or systemic anticancer treatments.

Idiotype regulatory networks promote autoantibody formation.

There is good evidence that the idiotypic network of the immune system can be implicated in the synthesis of pathogenic subsets of autoantibodies. The individual with systemic lupus erythematosus must have the immunoglobulin gene information which permits synthesis of those idiotypes, helper T populations which drive or select for the B cells producing them, and inadequate mechanisms to suppress those activated effector cells.

Sarcoid myopathy with elevated creatine phosphokinase.

Acute inflammatory myopathy complicating sarcoidosis is rare, and its prognosis and appropriate therapy have not been defined well. We describe a patient with chronic sarcoidosis who, during a 3-month period, developed an acute proximal myopathy associated with marked elevations in creatine phosphokinase (CPK) and extensive granulomatous inflammation on muscle biopsy. High-dose corticosteroids were dramatically effective in inducing remission, with resolution of all signs and symptoms of the myopathy and normalization of CPK.

Mechanisms of T and B cell collaboration in the in vitro production of anti-DNA antibodies in the NZB/NZW F1 murine SLE model.

B/W mice spontaneously develop IgG antibodies to DNA that cause lethal immune nephritis. T and B cell interactions in the in vitro anti-DNA antibody response of B/W mice were investigated, and two distinct families of helper T cells that drive these responses were defined. First, the anti-DNA antibody-forming cell (AFC) response was found to be increased in B/W mice with nephritis and was inhibited with the monoclonal antibody anti-L3T4, suggesting a major role for helper T cells. Purified splenic T cells from mice with nephritis were able to augment both the IgG and the IgM anti-DNA AFC response of young B/W B cells. T helper cells were cloned from spleens of NZB/W F female mice with high titer anti-DNA antibodies and nephritis. The cloned T cells augmented both IgG and IgM anti-DNA AFC responses of young B/W B cells. Four clones--27.9, 30.7, 30.8, and 30.10--were selected for further study. These cells proliferated, in the context of syngeneic (H2d/z) antigen-presenting cells (APC) but not to allogeneic APC. Analysis of the mechanism of T helper cell clone-mediated augmentation of anti-DNA AFC revealed two populations: "cognate" T helper cells, which specifically augment anti-DNA AFC (30.7 and 30.10), and non-antigen-specific T helper cells (27.9 and 30.8), which augment the response of B cells of differing specificity by a bystander mechanism, probably through increased release of B cell growth and differentiation factors.

Detection of native and denatured DNA antibody forming cells by the enzyme-linked immunospot assay. A clinical study of (New Zealand black x New Zealand white)F1 mice.

A new method for measuring DNA antibody forming cells (DNA-AFC) using the enzyme-linked immunospot (ELISPOT) assay is described. This method uses enzyme-linked immunosorbent assay (ELISA) techniques applied to cells cultured on DNA-coated plates, which allows visual quantitation of spots representing imprints of specific antibodies from DNA-AFC. Specificity for DNA was confirmed by inhibition studies and lack of reactivity by anti-lysozyme hybridomas. Isotypes of IgG and IgM can be measured using the appropriate antisera in the assay. A study of 16 female (New Zealand black x New Zealand white)F1 ([NZB x NZW]F1) female mice showed significant correlation between age, rising blood urea nitrogen levels, and increasing proteinuria and increasing numbers of DNA-AFC. In contrast, the correlation between circulating antibodies to DNA (ELISA method) and clinical parameters of nephritis was not significant. Both the native DNA ELISPOT and the native DNA ELISA had similar significant linear correlations with age. This is the first report of use of the ELISPOT assay for measurement of DNA-AFC. The DNA-AFC measured by this method were specific and correlated with the presence of clinical nephritis in (NZB x NZW)F1 mice. This method should allow further study on the regulation of DNA-AFC in vitro and in vivo, and will be useful in the investigation of DNA-AFC and cellular mechanisms of autoimmunity.

Encephalitogenic T cells in the B10.PL model of experimental allergic encephalomyelitis (EAE) are of the Th-1 lymphokine subtype.

T helper cells reactive to myelin basic protein are clearly implicated in the pathogenesis of murine EAE. We have developed a T cell line, BML-1 that (1) is reactive to the encephalitogenic amino terminal nonapeptide (1-9NAC) of MBP, (2) is I-Au restricted, and (3) induces relapsing EAE in B10.PL (H-2u) mice. Measurement of the lymphokine profile of BML-1 revealed secretion of IL-2, interferon-gamma and lymphotoxin but not IL-4. This profile is consistent with the Th1/DTH subtype. Coculture of BML-1 with MBP-primed B cells shows that BML-1 does not provide significant helper function in vitro. In addition, BML-1 secretion of interferon-gamma was found to inhibit LPS-induced anti-MBP antibody responses. This suggested that anti-MBP antibodies may not be necessary for induction of EAE. Sera from mice, in which severe disease was induced with the 1-9NAC peptide and Bordetella pertussis, showed no development of serum antibodies to MBP. These data show that MBP-reactive Th cells of the Th-1/DTH subtype can induce EAE and do not provide Th function for anti-MBP responses and that serum anti-MBP antibodies are not found in peptide 1-9NAC-induced disease. T cell lines specific for encephalitogenic epitopes and characterized for lymphokine secretion will provide a useful tool for understanding the role of T cells in the induction of EAE.

Inflammatory leukocytes and cytokines in the peptide-induced disease of experimental allergic encephalomyelitis in SJL and B10.PL mice.

Experimental allergic encephalomyelitis (EAE) was generated in SJL and B10.PL mice by using the synthetic myelin basic protein peptides. Inflammation in brain and spinal cord preceded clinical signs of disease. Infiltrating lymphocytes were predominantly Lyt1+ (CD5+), L3T4+ (CD4+) T cells, until day 18. After that, F4/80+ monocyte/macrophages outnumbered T cells. Ia+ cells were microglia, macrophages, and endothelial cells, but Ia was not detectable on astrocytes in this EAE model. Ia+ endothelial cells appeared later in the disease than Ia+ microglia and macrophages, suggesting that antigen presentation at the blood-brain barrier is not initially responsible for inflammation. Cells staining for interferon gamma, interleukin 2 (IL-2), and IL-2 receptors were more prominent than IL-4, IL-5, lymphotoxin (LT), and tumor necrosis factor alpha (TNF-alpha), which occurred transiently in the second week and were associated with fewer cells. TNF-alpha and LT were never seen in spinal cord, suggesting that these cytokines are not responsible for initiation of clinical disease. Few or no cells stained for IL-6, IL-1, or transforming growth factor beta. Control animals injected with complete Freund's adjuvant in saline or control antigen demonstrated no inflammatory cell infiltration or cytokine production. Thus, our findings suggest a peptide-induced EAE model in which Th1 T-cell-macrophage interactions result in the disease process.

Idiotypic spreading promotes the production of pathogenic autoantibodies.

We propose that a major immunoregulatory abnormality in murine and human autoantibody-mediated disease is idiotypic spreading. By this mechanism, B cells with the genetic information to produce immunoglobulin (Ig) bearing certain public idiotypes (Ids) are selectively upregulated, probably by Id-recognizing helper T cells. The model in which we are testing the hypothesis is systemic lupus erythematosus (SLE) in humans and NZB/NZW F1 (BW) female mice. Recent experiments have shown that the number of public Ids expressed on the Ig of nephritic BW mice is quite restricted. IdX is the dominant Id on serum Ig; IdGN1 and IdGN2 are also common. All three Ids were initially derived from spontaneous antibodies to DNA. Together the three are present on 85% of the total Ig repertoire. Such restriction suggests idiotypic spreading. In glomerular Ig deposits from nephritic BW mice, IdGN1 and IdGN2 are found on 45% of the total Ig: IdX is present in minute amounts. Furthermore, suppression of IdGNs by administration of anti-IdGN1 to BW mice resulted in significant delay in the onset of nephritis, but the IdGNs escaped from control and eventually caused a fatal nephritis. Finally, studies of glomerular Ig deposits in renal biopsies of patients with SLE have shown that IdGN2 dominates such Ig, being present in 76% of renal biopsies from SLE patients and in 6% from patients with non-lupus immune nephritis. Therefore, we have concluded that IdGN1 and IdGN2 are markers of nephritogenic subsets of autoantibodies and are probably the products of idiotypic spreading most likely to cause disease. Finally, after a review of recent experiments suggesting the dominance of autoreactive, Mossman Type 2 T helper cells in nephritic BW mice, it is hypothesized that autoreactive, IdGN-recognizing helper T cells may be central to the sustained upregulation of pathogenic autoantibodies in murine and human SLE.

Restricted use of T cell receptor V genes in murine autoimmune encephalomyelitis raises possibilities for antibody therapy.

Experimental allergic encephalomyelitis (EAE) is a paralytic autoimmune disease induced in susceptible animals by active immunization with myelin basic protein (MBP) or by passive transfer of MBP-specific T helper (TH) lymphocytes. We have analyzed the T cell receptor genes of 33 clonally distinct TH cells specific for a nonapeptide of MBP inducing EAE in B10.PL (H-2u) mice. All 33 TH cells used two alpha variable gene segments (V alpha 2.3, 61%; V alpha 4.2, 39%), the same alpha joining gene segment (J alpha 39), and two V beta and J beta gene segments (V beta 8.2-J beta 2.6, 79%; V beta 13-J beta 2.2, 21%). The anti-V beta 8 monoclonal antibody F23.1 was found to block completely recognition of the nonapeptide by V beta 8 TH cells in vitro and to reduce significantly the susceptibility of B10.PL mice to peptide-induced EAE.