Transfer of allergic encephalomyelitis in rats by means of lymph node cells

Peripheral nervous system lesions in experimental allergic encephalomyelitis. Ultrastructural distribution of T cells and Ia-antigen

The distribution of T cells and Ia-antigen in peripheral nervous system (PNS) lesions of experimental allergic encephalomyelitis was studied by light- and electron-microscopic immunocytochemical techniques. Sprague Dawley rats, sensitized with guinea pig spinal cord tissue, developed a biphasic disease with acute inflammatory and chronic inflammatory demyelinating lesions in the PNS. In both the acute non-demyelinating and the chronic demyelinating disease inflammatory infiltrates were composed of T cells and Ia-positive monocytes/macrophages. Dependent upon the stage of the disease a variable percentage of T-lymphocytes carried the Ox 8 antigen (suppressor/cytotoxic cells). In demyelinating lesions no evidence for an interaction of T cells with myelin or Schwann cells was observed, thus arguing against a direct T-cell cytotoxicity in demyelination. The whole sequence of myelin destruction and digestion was performed by W3/13-, Ia+ mononuclear cells with ultrastructural features of monocytes/macrophages. In contrast to the acute inflammatory stage of the disease, high titers of anti-myelin antibodies were present in sera of affected animals sampled during the chronic inflammatory demyelinating stage. The sera from the latter animals also showed pronounced in vivo demyelinating activity when transferred into the cerebrospinal fluid (CSF) of normal recipient rats. It is thus suggested that demyelination in this model is induced by a co-operation of cell-mediated and humoral immune mechanisms. We did not find evidence for Ia-antigen expression on local elements of the PNS (Schwann cells, axons, or endothelial cells).

Induction of experimental allergic encephalomyelitis in Lewis rats with purified synthetic peptides: delineation of antigenic determinants for encephalitogenicity, in vitro activation of cellular transfer, and proliferation of lymphocytes

Four highly purified synthetic peptides encompassing segments of the 68-86 region [for the numbering system used, see Eylar, E.H., Brostoff, S., Hashim, G., Caccam, J. & Burnett, P. (1971) J. Biol. Chem. 246, 5770-5784] of myelin basic protein (MBP), a region known to induce experimental allergic encephalomyelitis (EAE) in Lewis rats, were used to define and compare structure-function relationships between the primary structure of the 68-86 sequence and the three following biological activities: induction of EAE in Lewis rats, stimulation of T lymphocytes in vitro as measured by augmented cellular transfer of EAE to syngeneic recipients, and lymphocyte proliferation, as measured by [3]thymidine incorporation. Guinea pig (GP) MBP was approximately 60 or 1500 times more active than the GP68-84 (Y G S L P Q K S Q R S Q D E N; single-letter amino acid abbreviations) or the modified bovine (MB) 68-84 (Y G S L P Q K A Q R P Q D E N) peptides for induction of EAE, respectively. Furthermore, lymphocytes primed with either GPMBP, GP68-84, or MB68-84 crossreacted in vitro with either GPMBP, GP68-84, or MB68-84 for activation of lymphocyte transfer activity. In contrast, lymphocytes primed with either GP68-84 or MB68-84 exhibited antigen-specific proliferation in vitro exclusively in response to either GP or MB sequences, respectively. Neither GP75-84 (S Q R S Q D E N) nor GP75-86 (S Q R S Q D E N P V) induced EAE, activated lymphocytes for EAE transfer, or stimulated lymphocyte proliferation under conditions and doses tested. We conclude that (i) structurally distinct determinants, reflecting existence of functionally independent classes of antigen receptors, specify encephalitogenic and proliferative responses of primed lymphocytes and (ii) determinants for EAE induction, cellular transfer of EAE, and lymphocyte proliferation include amino acid residues in the 68-74 (Y G S L P Q K) sequence of GPMBP.

Effect of rat and beta-human interferons on hyperacute experimental allergic encephalomyelitis in rats

Human interferon-beta (human IFN-beta) and rat interferon (rat IFN) were evaluated on experimental allergic encephalomyelitis (EAE) in rats, a delayed cellular reaction resembling human multiple sclerosis (MS). Rat IFN was active by intravenous and intracerebroventricular routes. It decreased the severity of clinical symptoms of paralysis during the 22 days of the assay. Human IFN-beta, on the contrary, had no effect when similarly tested in this rat model. Cyclophosphamide delayed the onset of paralysis, but levamisole enhanced the severity of the EAE.

Preliminary analysis of cell and serum-induced demyelination in vitro using a syngeneic system

Previous studies on immune-mediated demyelination in vitro have usually tested sera and lymphoid cells in heterologous systems. The present study involved the examination of CNS cultures of SJL/J mouse spinal cord exposed to sera and lymphoid cells isolated from animals of the same strain previously injected with syngeneic spinal cord homogenate (SSCH) to induce acute experimental autoimmune encephalomyelitis (EAE). Examination of treated versus control cultures by light and electron microscopy at varying time points after exposure showed that spleen cells from animals with EAE produced significant demyelination and oligodendroglial cell destruction. Lymph node cells and sera from the same animals showed the same type of demyelination without marked oligodendroglial cell damage. The degree of myelin damage induced by spleen cells and sera did not correlate with the clinical status of the animal but a slight positive correlation was noted with lymph node cells. Cells and sera from control animals did not induce significant demyelination. These results suggest that in this syngeneic mouse system, there was a differential effect among cells from spleens and lymph nodes, and serum. This syngeneic system might allow for more meaningful pathologic and genetic analyses of immune-mediated demyelination.

Acute experimental allergic encephalomyelitis in the mouse: immunopathology of the developing lesion

To investigate the sequence of immunopathologic events during lesion formation in acute experimental allergic encephalomyelitis (EAE), SJL/J mice were inoculated with isogeneic spinal cord in complete Freund's adjuvant (CFA) and with Bordetella pertussis on Days 1 and 3 postinoculation (PI). Mice were sampled at different time points PI and T cells, T-cell subsets. Ia+ cells, Ig+ cells, albumin, and Ig deposits were localized in frozen sections by the avidin-biotin complex (ABC) method and direct fluorescence. Furthermore, samples were stained for Ia antigen, myelin basic protein (MBP), and galactocerebroside (GC) localization on endothelial cells by the ABC technique. Clinical and pathologic observations were correlated with the immunopathologic results. It was found that early in the disease process myelin and Ia-antigens were demonstrable on endothelial cells within the central nervous system (CNS). Simultaneously, damage to the blood-brain barrier was apparent, as indicated by albumin deposits, and small numbers of infiltrating T cells, T-cell subsets, and Ia+ cells were found. With time PI, the density of infiltrating total T cells (Thy-1.2+), helper/inducer (Lyt-1+), and suppressor/cytotoxic (Lyt-2+) T cells increased; Lyt-1+ and Lyt-2+ cells were detectable in meningeal as well as parenchymal infiltrates, while later on, Lyt-1+ cells showed some predilection for the CNS parenchyma and Lyt-2+ cells for meninges. Ia+ cells (B cells, macrophages, activated T cells) were present in small numbers only. Ig+ cells (B cells and macrophages) appeared shortly before onset of signs and persisted in moderate numbers. These results reconfirm the importance of early T-cell involvement for the development of EAE; they might also indicate a secondary role for Ig+ cells and are consistent with the concept that presentation of myelin antigens to T cells might occur locally on Ia-bearing endothelial cells within the CNS.

Modulation of experimental allergic encephalomyelitis in Lewis rats by monoclonal anti-T cell antibodies

The effect of monoclonal antibodies to different T lymphocyte populations of the rat on the induction and the course of experimental allergic encephalomyelitis (EAE) was investigated. EAE was induced by injection of guinea pig spinal cord in adjuvant. Subcutaneous injections of monoclonal antibodies to all peripheral T lymphocytes (W3/13) abrogated or prevented the development of clinical EAE. Similar results were obtained in animals injected with monoclonal antibodies to T helper cells (W3/25) mixed with monoclonal antibodies to T nonhelper cells (OX8). Animals treated with either W3/25 or OX8 developed clinical EAE as the control rats (subcutaneous injected with normal mouse serum). Histological examination after the acute stage revealed no significant differences between rats treated prophylactically with W3/13, W3/25 or OX8 and rats injected with normal mouse serum. Animals treated prophylactically with a mixture of W3/25 and OX8 developed, on the whole, EAE with less histological severity compared to the control animals. Treatment of rats after the onset of the first clinical symptoms of EAE (tail flaccidity) with W3/13 resulted in a less fatal course of the disease. Compared to surviving rats injected with mouse serum (controls) the number of infiltrates were reduced in these rats treated therapeutically.

Serum and cells from Theiler's virus-infected mice fail to injure myelinating cultures or to produce in vivo transfer of disease. The pathogenesis of Theiler's virus-induced demyelination appears to differ from that of EAE

Intracerebral inoculation of SJL mice with Theiler's Murine Encephalomyelitis virus (TMEV) results in a biphasic disease characterized by early grey matter involvement followed by late, chronic white matter inflammation and demyelination. Morphological parameters of TMEV-induced demyelination are essentially identical to those of experimental allergic encephalomyelitis (EAE) and immunosuppression has been shown to prevent demyelination. To test whether the pathogenesis of demyelination in TMEV infection is based on an autoimmune attack on myelin as in EAE, we tested sera and cells from infected animals for their ability to produce in vitro demyelination and cells for their ability to transfer disease in vivo. Isogeneic organotypic cultures were exposed to either serum or splenocytes from diseased animals. Neither serum nor splenocytes demyelinated or prevented myelination in these cultures. Splenocytes from diseased animals were also incubated with basic protein or whole spinal cord and assayed for their proliferative response or their ability to transfer disease to naive recipients. Neither proliferation nor transfer of disease was observed. These results show that the immunopathology of demyelination in the Theiler's model differs from that of EAE in a number of important parameters and support the contention that demyelination in this viral infection is produced by immunological mechanisms different from those operating in EAE.

Canine distemper and experimental allergic encephalomyelitis in the dog: comparative patterns of demyelination

The pattern of virus-induced and allergic demyelinating encephalomyelitis in the dog were compared. The predominant pattern of myelin loss in canine distemper (CD) infection was focal, periventricular and was initially noninflammatory. In contrast, sensitization to myelin produced a uniform pattern of central nervous system (CNS) myelinolysis which was disseminated, inflammatory and perivascular. Ultrastructurally, virus-infected neuroglia participated in the demyelination in CD, whereas infiltrating haematogenous mononuclear cells predominated in the lesions of experimental allergic encephalomyelitis (EAE). Areas of predilection within the CNS differed, being influenced by viral spread in CD and by vascular factors in EAE. In CD, the paramyxovirus appears to play a central role in the process of demyelination. In contrast to EAE, however, these studies do not support the view that autoreactivity to myelin contributes to the pathogenesis of CD demyelinating encephalomyelitis.

Attempts to transfer experimental allergic neuritis with lymphocytes

Attempts have been made to transfer experimental allergic neuritis (EAN) both by the intraneural and the intravenous injection of cells derived from Lewis rats with the disease into naive recipients of the same strain. Lymph node cells obtained 12 and 15 days after inoculation with bovine dorsal root in Freund's complete adjuvant were injected intraneurally. A small number of demyelinated axons were observed, but clinical weakness was not evident. Lymph node cells, lymph node cells cultured with concanavalin A, or cultured spleen cells from animals with EAN were transferred intravenously to normal rats. Uncultured lymph node cells were transferred to X-irradiated animals. There were no clinical or histological differences between these recipients and controls receiving cells from rats inoculated with Freund's adjuvant alone. The findings are discussed in relation to previous reports of attempts to transmit EAN by cell transfer.

Mononuclear cell accumulation and plasma protein extravasation (PPE) during induction, remission and re-challenge of experimental allergic encephalomyelitis in the rat

Plasma protein extravasation (PPE) and cell accumulation have been studied in the CNS of rats during experimental allergic encephalomyelitis (EAE) using radioisotopic techniques. Use of such techniques makes it possible to study objectively and conveniently the rate of cell infiltration and PPE during the disease process in relation to clinical signs and time after immunization. The following observations have been made: After the first immunization, the number of rats showing increased PPE in the CNS correlated well with the severity of EAE. Mononuclear cell infiltration into brain and spinal cord during EAE did not parallel one another; infiltration being of earlier onset and shorter duration in the spinal cord, in comparison with brain. Animals re-challenged with encephalitogenic antigen showed considerably increased cellular infiltration into the brain but failed to exhibit comparable infiltration in the spinal cord. In this case infiltration of cells is not accompanied by increased PPE, in contrast to what is seen during primary disease. Increased infiltration into the brain of re-challenged animals appears, therefore, unrelated to gross damage of vascular endothelium.

Mononuclear lymphoid populations infiltrating the microenvironment of primary CNS tumors. Characterization of cell subsets with monoclonal antibodies

Mononuclear cell infiltrates are found to varying degrees in 30% to 60% of primary human central nervous system (CNS) gliomas. To explore the immunological importance of this, six operative glial tumors, eight non-glial tumors, and three normal brain specimens were studied. Utilizing an immunoperoxidase method, the authors examined frozen sections for lymphoid infiltrates expressing suppressor/cytotoxic and helper phenotypes, as identified with the Leu-1,2,3 monoclonal antibodies. Four of six gliomas demonstrated lymphoid infiltrates: three tumors exhibited a predominant suppressor/cytotoxic cell phenotype and the fourth showed mixed staining of suppressor/cytotoxic and helper cell phenotypes. Varying degrees of lymphoid infiltration characterized four out of eight non-glial primary CNS tumors. Two cases exhibited a prevalence of suppressor/cytotoxic phenotype cells, while two cases demonstrated a more heterogeneous pattern of phenotype expression. Normal brain sections revealed little or no evidence of mononuclear infiltrates. The immunobiological significance of these findings is discussed in the context of tumor-host interaction within the CNS.

Adoptive transfer of myelin basic protein-sensitized T cells produces chronic relapsing demyelinating disease in mice

The autoimmune disease of the central nervous system (CNS), experimental allergic encephalomyelitis (EAE), is induced by challenge of genetically susceptible animals with spinal cord homogenates or myelin basic protein (MBP). Chronic and relapsing forms of the disease have some similarities to human demyelinating disorders, namely, multiple sclerosis, and are of particular interest. EAE can be transferred passively with sensitized lymphoid cells into syngeneic animals but transferred EAE has been believed to have limited relevance to human disease because it is usually monophasic and manifested by minimal demyelination. We report here that a single transfer of MBP-sensitized lymph node cells or T cell, in the absence of a peripheral antigen depot, leads to both acute EAE with significant primary demyelination, and chronic relapsing disease with lesions typical of demyelination over a long period. These findings have major implications for the immunological mechanisms involved in experimental and human demyelinating diseases.

The suppression of mitogen responses associated with resistance to experimental autoimmune encephalomyelitis requires adherent and T cells

Resistance to experimental autoimmune encephalomyelitis (EAE) in Hartley guinea pigs has previously been reported to be associated with disease-specific antigen-induced suppression of mitogen responses in vitro. The present studies were initiated to investigate the requirement for different cell populations in this suppression. Intact and adherent-cell-depleted cultures of spleen cells from experimental and control animals were incubated with myelin basic protein (MBP), the major antigen of EAE, with the T-cell mitogen concanavalin A (Con A) alone or with Con A in the presence of MBP. In agreement with previous studies, MBP-induced suppression of the Con A response was observed only in cultures derived from resistant animals. In addition, it was observed that this suppression was abrogated by depletion of adherent cells. When cells from resistant and susceptible animals were mixed, suppression occurred only in the presence of nonadherent cells from resistant guinea pigs. Adherent cells from either resistant or susceptible animals functioned equally well. Cultures of purified E-rosette-forming cells (E+) from resistant animals (i.e., T cells) showed no suppression. Similarly, cells from these same animals which were depleted of E+ cells (i.e., non-T cells) did not demonstrate suppression in vitro. Upon reconstitution of spleen cell populations from resistant guinea pigs by mixing E+ and E- cells, suppression was restored. These experiments show that this model of suppression in vitro requires adherent cells as well as T cells and suggests that antigen-induced suppression of mitogen responses is dependent upon a cell-mediated immunologic mechanism.

Ultracytochemical distribution of myelin basic protein after injection into the cerebrospinal fluid. Evidence for transport through the blood-brain barrier and binding to the luminal surface of cerebral veins

Distribution of myelin basic protein (MBP) in the central nervous system (CNS) following injection into the cerebrospinal fluid (CSF) was studied by different qualitative and quantitative immunelectron -microscopic techniques. Endogenous MBP was present in myelin sheaths in injected as well as in control animals. After injection of exogenous MBP into CSF this protein was present in the subarachnoid space, on the surface of meningeal cells, on the surface of collagen fibers, in the basement membrane of the glia limitans, in vessel walls, and in the extracellular space of spinal roots. In meningeal veins, endothelial vesicles filled with peroxidase reaction product were found on the abluminal side of endothelial cells, in the endothelial cytoplasm and sometimes opening into the vascularllumen . In addition patchy staining of the luminal surface of endothelial cells was noted, indicating binding of antigen at this location. Quantitative immunelectron microscopy (an indirect technique with rabbit anti-MBP serum as primary layer and gold-labeled anti-rabbit IgG as secondary layer) revealed highly significant MBP binding on the luminal surface of endothelial cells after injection of this antigen into the CSF. The present results indicate that MBP, when liberated in CNS is transported through the blood-brain barrier and presented on the luminal surface of endothelial cells of the cerebral and meningeal veins. This observation may be important in interpretation of pathogenesis of initial inflammatory infiltrates in experimental allergic encephalitis (EAE).

Delayed type skin response to myelin basic protein in chronic relapsing experimental allergic encephalomyelitis

The skin response to myelin basic protein (MBP) was studied in chronic relapsing experimental allergic encephalomyelitis (EAE) using strain 13 guinea pigs. The delayed type skin response showed a monophasic curve; it gradually increased after immunization, reached maximum levels around 80 days post-immunization, and decreased thereafter. Relapses were more frequent while it was at high levels although it did not correlate directly in individuals with the clinical stage. The skin response was also high in MBP-immunized animals which had recovered from acute EAE. Our results suggest that delayed type hypersensitivity to MBP is involved but is not sufficient by itself to cause relapsing EAE.

Immune cell populations in cutaneous delayed-type hypersensitivity

Delayed-type hypersensitivity (DTH) is a prototypic T lymphocyte-mediated response to antigenic challenge. In this study, mononuclear cells infiltrating the skin during cutaneous response to tuberculin in presensitized human subjects (responders) and nonimmune controls were identified using monoclonal antibodies by indirect immunofluorescence. In both responders and controls the infiltrate consisted mainly of T lymphocytes (T11+ and OKT3+) and monocytes (OKM1+, 63D3+, Mo2+) which initially accumulated in proximity to small blood vessels and later infiltrated the interstitial dermis and epidermis. More T lymphocytes reacted with OKT4 than with OKT8. 6 h after tuberculin the ratio of OKT4/OKT8 in tissue from responders exceeded that in blood, whereas in tissues studied at 15-48 h and in all control tissues those ratios in blood and tissue were similar. Evidence of T lymphocyte activation was sought using monoclonal antibodies anti-Tac, OKT9, and OKT10. In responders but not in controls the proportion of infiltrating cells reactive with these antibodies increased during the course of DTH. The presence of activated T lymphocytes in tissue was not associated with a comparable increase in peripheral blood cell populations identified by anti-Tac and OKT10. Studies using anti-B1, Leu-7, and anti-IgD/IgM revealed comparatively few reactive cells. Dual-labeling studies demonstrated that most Leu-7--reactive cells also bound T11 while fewer bound OKM1 or OKT8 and that cells reactive with OKIa1 and T11 constituted largely nonoverlapping populations. Specific patterns of reactivity were not observed when tissues were stained with anti-human C3, or poly C9-MA, a monoclonal antibody reactive with a neoantigen on polymerized C9 of the membrane attack complex of complement. The number of epidermal Langerhans cells identified by OKT6 was similar in responders and controls. Thus, the cutaneous response to tuberculin in sensitized individuals is characterized by early enrichment of the OKT4 subpopulation of T lymphocytes in tissue infiltrates and subsequent (15-48 h) evidence of T lymphocyte activation.

Immunoglobulin-deficient rats fail to develop experimental allergic encephalomyelitis

Lewis rats were treated from day of birth with a rabbit anti-rat IgM antiserum. As adults these animals were found to have no detectable serum IgM and greatly reduced levels of IgG. They failed to respond to the B-cell mitogen LPS, or to make antibodies to sheep red blood cells (SRBC) or myelin basic protein (BP). These B-lymphocyte and immunoglobulin-deficient rats failed to develop clinical or histological evidence of EAE when sensitized with either whole spinal cord or purified BP. That some T-cell functions of these suppressed animals were not altered was seen by their ability to respond normally to PHA and to reject tissue allografts. The results would suggest that B-cell function (immunoglobulin-antibody production) is essential for the induction of EAE.

Attachment of myelin to coated pits on macrophages in experimental allergic encephalomyelitis

In experimental allergic encephalomyelitis (EAE) invading macrophages appear to destroy the antigen-containing region of the plasma membrane of the myelinating cell, leaving the cell body intact. We report here that during myelin destruction and phagocytosis, myelin lamellae are attached to coated pits on the macrophage surface. As coated pits are sites where receptor-ligand complexes concentrate prior to endocytosis, we conclude that ligand-mediated phagocytosis may explain the targeted activity of macrophages in autoimmune demyelination.

Induction of immune responses in vivo with small numbers of veiled (dendritic) cells

The role of dendritic or veiled cells (VC) from lymph nodes or spleens of rats and mice in initiating immune responses in vivo has been investigated. Host-versus-graft responses were induced by injection of VC from spleens of (C57BL/10 X CBA) F1 mice into the footpads of parental strain (CBA) animals and measured by the increase in the weight of the draining popliteal lymph nodes. The potency of VC to induce the responses was 100-fold greater than that of unseparated spleen cells. The in vivo effect of VC was not limited to this direct allogeneic stimulation because autologous VC could also be used in the induction of an experimental autoimmune disease. In these studies, experimental allergic encephalomyelitis was produced in Lewis rats by injection of guinea pig brain and spinal cord material emulsified in Freund's complete adjuvant. Small numbers of VC from spleens or lymph nodes of rats showing clinical signs of experimental allergic encephalomyelitis induced a mild form of the disease when injected intravenously into normal Lewis rats. Thus, VC carrying antigen, either as an integral part of their surface membrane or acquired during exposure to antigenic substances, appeared to be very potent agents for the induction of immune responses.

Chronic relapsing experimental allergic encephalomyelitis: its value as an experimental model for multiple sclerosis

Comparison of the pathohistology of chronic relapsing experimental allergic encephalomyelitis (CR-EAE) and multiple sclerosis (MS) reveals a close similarity. Thus, CR-EAE appears to be a valuable model for the study of pathogenetic factors leading to the formation of MS lesions, although the induction of the disease may be different (active sensitization with CNS antigens and adjuvant in CR-EAE versus unknown etiology in MS). CR-EAE furthermore mimicks the pathohistological patterns of other related human inflammatory demyelinating diseases (i.e., acute perivenous leukoencephalomyelitis and acute hemorrhagic leukoencephalomyelitis). The expression of an acute, predominantly inflammatory versus chronic inflammatory demyelinating disease in this model depends upon the time interval between sensitization and sampling of the animals. Recent evidence is discussed that a cooperation between cellular and humoral immune mechanisms, directed against multiple CNS antigens, is responsible for the formation of large demyelinated plaques in EAE and MS.

In vivo demyelinating activity of sera from animals with chronic experimental allergic encephalomyelitis. Antibody nature of the demyelinating factor and the role of complement

Sera from guinea pigs and rats with chronic experimental allergic encephalomyelitis were injected into the cerebrospinal fluid (CSF) of normal recipient rats. Guinea pig sera induced demyelination in the central and (or) peripheral nervous system, whereas injection of rat sera resulted in demyelination in the peripheral nervous system only. Control sera did not induce demyelination. Demyelinating activity in guinea pig sera was confined to the IgG-fraction; in rat sera the IgG- as well as the IgM-fraction were able to induce demyelination. The demyelinating activity was abolished when the sera were absorbed with with sensitising antigen (guinea pig spinal cord tissue) or when immunoglobulins were removed from the sera. When chronic EAE sera from rats were injected into the CSF of rats, complement was not required for the induction of demyeLination. The presence of complement, however, augmented the demyelinating activity. Decomplemented chronic EAE sera from guinea pigs failed to induce demyelination after injection into the CSF of rats. Injection of control and non-demyelinating or demyelinating EAE sera into the subarachnoid space of normal recipient rats induced a weak inflammatory response with increased numbers of large mononuclear cells in the meninges. It is discussed that in vivo a complex interaction of antibodies, complement and effector cells is responsible for induction of demyelination.

An explanation of prevention and suppression of experimental allergic encephalomyelitis

An explanation of experimental allergic encephalomyelitis prevention and suppression is presented based upon evidence that the active unit in disease induction is an encephalitogen-adjuvant complex. The stereochemical complementarity in structure of the encephalitogen and adjuvant is mirrored in complementarity in the recognition sites of lymphocyte populations activated against encephalitogen and adjuvant. Since two complementary lymphocyte populations are necessary for disease induction, any procedure that prevents the development of one of these populations will prevent disease induction. Any procedure that eliminates one population after induction has occurred will suppress the disease. We argue that all extant data support the hypothesis. Several new experiments are proposed to further test it.

Immunopharmacological studies on experimental glomerulonephritis

Immunopharmacological studies on modified nephrotoxic serum (NTS) nephritis in rats were conducted. The modified NTS nephritis was produced by an intravenous (i.v.) injection of NTS in a subnephrotoxic dose (sub-dose) into the rats which had been previously immunized with rabbit IgG (RGG) and complete Freund's adjuvant (CFA). In previously immunized rats, typical nephritic syndrome was demonstrated with respect to the elevation of urinary protein, serum cholesterol, blood urea nitrogen (BUN) and histopathologic scores of the kidneys. No changes in complement levels were found. By adoptive transfer experiments, it was found that sensitized lymphocytes were essential for causing the nephritis. The potency of the sensitized lymphocytes was reinforced by passing them through a nylon wool or Sephadex G-10 column after treatment with rabbit anti-rat F(ab')2 antibody and complement. The administration of cyclophosphamide, prednisolone, tilorone or cis-1-methyl-4-isohexylcyclohexane carboxylic acid (IG-10) showed a clear remission of nephritis. Cobra venom factor (CoVF) and Cu-chlorophyllin complement inhibitors showed a contradictory efficacy on the nephritis. CoVF which decreased the serum CH50 value did not produce any remission of the nephritis, whereas Cu-chlorophyllin, which slightly decreased CH50 values produced a significant decrease in urinary protein and serum cholesterol. The macrophage-toxic agents carrageenan and dextran sulfate, also did not produce a remission of nephritis. These findings suggest that the participation of T cells is important for the onset of this nephritis and that macrophages and complement do not appear to be involved.

Etiology and pathogenesis of monophasic and relapsing inflammatory demyelination - human and experimental

The close similarity of the CNS lesions in cr-EAE and MS renders this model especially valuable for the study of pathogenetic factors, leading to the formation of inflammatory demyelinated plaques. Recent evidence indicates, that various immune reactions, directed against different CNS antigens cooperate in the formation of the plaques. Furthermore it is discussed, that a combination of virus infection and autoimmunity may result in similarity structured lesions. It is thus propose that multiple different etiologic factors (autoimmune as well as exogenous events) may lead to the clinical pathohistological syndrome of multiple sclerosis.

Circulating myelinotoxic factors in human and experimental demyelinative disease

Demyelinating agents in demyelinating diseases have been analysed using organoid cultures of the nervous tissue. The agents can be classified into humoral and cellular factors. Humoral factor is complement C3 dependent IgG antibody against glycolipids, such as galactocerebroside, sulfatide and ganglioside. Antigenicity of these glycolipids seems to be species specific. Other than rabbits, vulnerability seems to be low. Demyelinating pattern in vitro produced by application of antisera and patient sera are characterized by enhancement of activities of the macrophages. Adhesion of activated cells to myelin, penetration, loosening, splitting and vesicular dissolution of myelin lamellae are characteristic features. Hapten antigen described above also induces myelination inhibiting antibody, which interferes with in vitro myelination. Cellular factors are characterized by lymphotoxic effects and activation of macrophages. These alterations are identical to those by lymphokines liberated from T lymphocytes. Effects of humoral factors can be seen only in limited animal species, whereas cellular factors affect overall animals, suggesting the cellular factors play the major role in the processes of demyelination.

Intraneural injection of lymphocytes in experimental allergic neuritis

Passive transfer of experimental allergic neuritis (EAN) lymph node cells (LNC) by intraneural injection did not produce significant demyelination. EAN-LNC stimulated with myelin in vitro produced mild demyelination while those incubated with Concanavalin A had no effect. The lack of demyelination by unstimulated EAN-LNC is in contrast to the marked demyelination produced by intraneural injection of EAN serum. The mononuclear cell infiltration and demyelination of classical EAN seem to require both cellular and humoral immune responses.

Transfer of lesions of allergic encephalomyelitis in sheep with cell-free lymph from animals sensitized with homologous spinal cord plus adjuvant

An experiment was designed to test the hypothesis that the inability to transfer experimental allergic encephalomyelitis (EAE) with serum from sensitized animals was due to the absorption, from the serum, of the relevant antibodies by the target organ of the donor. The immune response to central nervous system (CNS) antigens was isolated to a single lymph node, and the cell-free lymph coming from the node was shown to transfer lesions of EAE to naive recipients. These results are compatible with the hypothesis; however, the antibody nature of the transfer activity has yet to be established.

Cancer and depression: cancer presenting with depressive illness: an autoimmune disease?

It is proposed that some cases of depressive illness in cancer patients may be caused by immunological interference with the activity of serotinin, one of the neurotransmitters thought to be implicated in depression. This interference could be mediated in two ways. Antibody induced against a protein released from cancer cells could, on the basis of cross-reactivity with CNS tissue, bind to receptors for serotonin and block them. Such primary antibodies could stimulate the production of anti-idiotypic antibodies, which would act as an alternative receptor for serotonin and reduce its synaptic availability.

Effect of indomethacin treatment upon actively-induced and transferred experimental allergic encephalomyelitis (EAE) in Lewis rats

Daily administration of indomethacin (5 mg/kg) to Lewis rats from day 7 through day 21 following sensitization to guinea-pig spinal cord neural antigen plus Freund's complete adjuvant (FCA) resulted in an aggravation of clinical signs of EAE accompanied by a higher mortality. In contrast, lymph node cells (LNC) from sensitized and drug-treated donor rats showed decreased EAE transfer activity. The in vitro Con A response of LNC from sensitized, indomethacin-treated rats was comparable to those of normal LNC or LNC from sensitized animals only. The spleen cell response of sensitized rats was significantly lower than the response seen in normal animals, but was returned to normal levels in sensitized, indomethacin-treated animals. We believe these observations reflect an indomethacin-mediated diminished accumulation of EAE effector cells within peripheral lymph node tissues together with abrogation of splenic suppressor cell activity by indomethacin-mediated inhibition of prostaglandin (PG) synthesis in Lewis rats sensitized and treated with this drug under the conditions defined.

Syngeneic sensitization of mouse lymphocytes on monolayers of thyroid epithelial cells. III. Induction of thyroiditis by thyroid-sensitized T lymphoblasts

During in vitro sensitization of CBA spleen lymphocytes on syngeneic monolayers of either thyroid epithelial cells (TEC) or fibroblasts, stimulation occurs, as assessed by thymidine incorporation and lymphoblast generation. When lymphoblasts generated on syngeneic TEC are injected either into thyroid lobes of intact CBA recipients or i.v., thyroiditis appears at least 21 days after injection. Thyroiditis is assessed by both optical and electron microscopic blind studies and by the presence of antibodies in the sera directed against mouse thyroglobulin. In contrast, control animals which received identical numbers of lymphoblasts generated on syngeneic fibroblasts behaved as normal. Thyroiditis was also induced using pure thyroid-sensitized T lymphoblasts. This is the first report showing the role of T lymphocytes in the induction of experimental autoimmune thyroiditis.

Antibodies-restricted heterogeneity in serum and cerebrospinal fluid of chronic relapsing experimental allergic encephalomyelitis

An animal model which might help to study multiple sclerosis has long been sought. With chronic relapsing experimental allergic encephalitis (EAE), the search seems to have brought hope and evidence of comparable pathology whether concerned with clinical or neuropathological results, but no study of the cerebrospinal fluid (CSF) electrophoretic pattern has been made so far. A new sensitive method enables to study the CSF proteins: unconcentrated CSF proteins after agar gel electrophoresis are stained with silver reagents. The silver technique allows to follow the evolution of the inflammatory reaction in chronic relapsing EAE as well as in the acute form of EAE. This technique provides an additional approach to the study of EAE and an argument in favor of chronic relapsing EAE in guinea pigs as a model for multiple sclerosis.

Goblet cell glycoprotein: an organ-specific antigen for gut. Isolation, tissue localization and immune response

We report, for the first time, immune responses within two lines of inbred rats to a purified Lewis rat glycoprotein antigen which is organ-specific for intestine. The antigen was prepared by solubilization of gut epithelial cell-associated macromolecules, fractionation in ethanol, and molecular sieve chromatography over Sepharose 2B. Homogeneity of the end product (RGCG-PK1) was supported by results of both double diffusion in agar and SDS polyacrylamide gel electrophoresis. Amino acid analysis and specific sugar determination proved that RGCG-PK1 was not a classical mucin because of its comparatively high tyrosine and low galactosamine + glucosamine content, and the absence of glycosidic linkages to serine and threonine. Organ-specificity was shown by the ability of RGCG (but not liver homogenate) to inhibit precipitation and haemagglutination by heterologous specific sera. Organ-specificity was confirmed by the demonstration of RGCG-PK1-specific immunofluorescence staining of rat small and large intestine, but not esophagus, stomach or liver. RGCG-PK1 determinants within rat and human small bowel were found to be confined to goblet cells and intestinal glycocalyx. Anti-RCGC-PK1 serum showed no reactivity with highly purified xenogeneic mucins nor with syngeneic small bowel mucin. Specific antibody (as well as antibody-dependent cellular cytotoxicity) to RGCG was elicited and detected for up to 10 days in two lines of inbred rats, including the one (Lewis) from which the antigen was isolated. The duration and peak of the humoral immune response were abbreviated compared with that of a xenogeneic control glycoprotein studied in parallel, probably due to immunoregulatory mechanisms operative for self antigens.

Cellular cytotoxicity and gastrointestinal inflammation in inbred rats: induction with gut organ-specific antigens

Although the ability to induce with organ-specific antigens autoimmune inflammatory lesions in the brain and thyroid is well-established, it has not been accomplished for the gastrointestinal system. Therefore, purified rat intestinal glycoproteins (RGCG and RCG) with defined biochemical and immunological properties and known to be organ-specific, were employed to study immune responses in four highly inbred strains of rats. Animals subcutaneously immunized with RGCG/RCG (or saline in controls) and Mycobacterium butyricum as the primary adjuvant were followed weekly for (a) weight loss and diarrhoea; (b) development of specific antibody; (c) cell-mediated cytotoxicity by a ⁵¹Cr release assay; (d) pathological changes (graded I—IV) in intestine at the time of serial killing; and (e) increase in lamina propria cell count in histological sections taken from both macroscopically normal and abnormal bowel wall.

Disease incidence was highest in LOU/Mn strain rats injected with RCG, where small bowel lesions began at the fifth week after immunization (one of three animals), their frequency progressively increasing through the seventh week (four of five animals) when weight loss was most marked. Lewis strain rats injected with RCG had similar small bowel lesions at the sixth and seventh week. Colonic lesions were found in LOU/Mn strain rats injected with RGCG. Antibody-dependent cellular cytotoxic responses to RCG were detectable at both 50:1 and 10:1 effector to target ratios, occurred principally in injected animals who progressed to disease, and were correlated in time with the onset of lesions (weeks 5–7). Pathologically, all small bowel lesions were grade III (dark red granular mucosa) or IV (granular with obvious haemorrhage). Involved segments were 4–16 cm long, confined to the ileum, and diffuse without punctate ulcers. Colonic lesions were 2 cm long and diffusely hyperemic (grade II). Histologically, sections from diseased animals showed three changes: distortion (blunting) of villus shape, a hypercellular lamina propria (grade, moderate) and disruption of columnar epithelial lining cells. Two (ACI and Wistar—Furth) of the four strains studied were non-responders with respect to disease induction. We conclude that purified organ-specific gut glycoproteins can induce bowel wall pathological changes and antibody-dependent cellular cytotoxic reactions in susceptible strains of immunized rats. This technique may be useful for studying both the origin of, and the mediators for, autoimmune disease of the intestine.

Immunological aspects of intrinsic glial tumors

✓ Fundamental concepts of general tumor immunology and modes of immunotherapy are presented. Significant work dealing with the relationship of the immune system to intrinsic glial neoplasms is reviewed in relation to therapeutic applications and future investigative efforts.

Induction of lethal experimental allergic encephalomyelitis in nonhuman primates and guinea pigs with human glioblastoma multiforme tissue

✓ The introduction of active specific immunotherapy as an adjunct to conventional therapy of the brain-tumor patient creates the risk of the concomitant induction of experimental allergic encephalomyelitis (EAE). The lack of resolution concerning the total group of central nervous system (CNS) antigens which may be encephalitogenic, and the lack of definition of the necessary conditions for the induction of an anti-CNS myelin response complicate the design of an immunotherapeutic regimen for brain-tumor patients. We report here the ready induction of EAE in four of four guinea pigs and both of two nonhuman primates (Macaca fascicularis) with human glioblastoma multiforme (GBM) tissue injected with either complete or incomplete Freund's adjuvant (CFA, IFA). Immunization protocols utilizing encephalitogenic GBM tissue and adjuvant which did not result in EAE induction were established in both of two macaques, and the production of significant levels of antibodies specifically reactive with immunizing GBM-derived cultured cell lines in all of 12 macaques without EAE induction was demonstrated. As the lower detection limit of the sodium dodecyl sulfate-polyacrylimide gel electrophoresis (SDS-PAGE) assay for human myelin basic protein (HBP) was 0.6 µg HBP/gel, and an extract prepared from WR-GBM tumor tissue contained less than 0.6 µg of detectable HBP/25 µg of pH 3 extractable protein, and as 100 to 1000 µg of purified human basic protein (HBP) failed to induce EAE in three of three macaques, it was hypothesized that 1) GBM tissue may act as an adjuvant and markedly lower myelin basic protein (MBP) threshold doses for EAE induction, that 2) MBP encephalitogenic fragments capable of EAE induction may be present in GBM tissue but difficult to quantitate in precipitates by in vitro methods, or that 3) secondary encephalitogenic antigens unrelated to MBP may be present in GBM tissue. The threat of EAE induction and the potential difficulty of its detection in the deteriorating brain-tumor patient receiving active specific immunotherapy warrants a biological screen in immunizing CNS material in experimental animals prior to administration to patients in immunotherapy protocols.

Successful immunization against experimental allergic encephalomyelitis with myelin basic protein-sensitized allogeneic lymphocytes

Prevention and suppression of experimental allergic encephalomyelitis were demonstrated in rats, guinea pigs, and rabbits immunized with allogeneic, but not with syngeneic lymphocytes from susceptible donors sensitized to myelin basic protein (MBP). Donor lymphnode, splenic, or peripheral blood lymphocytes were effective in inducing a state of unresponsiveness to an encephalitogenic challenge in either of the three species. Unresponsiveness was not obtained in recipients immunized with sensitized allogenic lymphocytes and simultaneously challenged with MBP suggesting that a time lapse between immunization and challenge is necessary for the development of protective immunity. Induced in immunized recipients, unresponsiveness was transferred into normal syngeneic recipients with immunoglobulin-G (IgG) isolated from protected donors before challenge. Furthermore, both immunized and IgG recipients failed to develop cell-mediated immunity after challenge with MBP. The results show that prevention and suppression of EAE was mediated by antibodies which inhibited the development of delayed type hypersensitivity to the challenging antigen.