Adoptive Transfer Of Experimental Allergic Encephalomyelitis Research Articles

Immune Invasion of the Central Nervous System Parenchyma and Experimental Allergic Encephalomyelitis, But Not Leukocyte Extravasation from Blood, Are Prevented in Macrophage-Depleted Mice

Organ-specific autoimmune diseases are characterized by infiltrates, including T lymphocytes and activated macrophages. Macrophages and secondarily activated tissue resident counterparts can both present Ag to and contribute to cytokine secretion by T lymphocytes. We have previously shown a crucial role of peripheral macrophages in experimental allergic encephalomyelitis (EAE), a Th1-mediated demyelinating disease that serves as a an animal model for multiple sclerosis (MS), by their depletion using mannosylated liposome-encapsulated dichloromethylene diphosphonate (Cl2MDP). Here we describe studies to investigate the mechanisms by which macrophages contribute to the lesion formation in EAE, by studying the effect of Cl2MDP-containing mannosylated liposomes (Cl2MDP-mnL) on adoptively transferred EAE in SJL/J mice. Adoptive transfer of EAE with myelin basic protein-reactive CD4+ T cells to SJL/J mice was abrogated by Cl2MDP-mnL treatment. CD4+ T cell and MHC II+ B220+ B cell extravasation from blood vessels and Th1 cytokine production were not inhibited. However, invasion of the central nervous system intraparenchymal tissues by lymphocytes, F4/80+, Mac-1+, and MOMA-1+ macrophages was almost completely blocked after treatment with Cl2MDP-mnL. Furthermore, in Cl2MDP-mnL-treated mice, the myelin sheaths appeared completely normal, whereas, in the control groups, marked demyelination occurred. Production of TNF-alpha and inducible nitric oxide synthase, both associated with macrophage/microglial activation, was inhibited. This intervention reveals a role for macrophages in regulating the invasion of autoreactive T cells and secondary glial recruitment that ordinarily lead to demyelinating pathology in EAE and multiple sclerosis.

Enhancing effects of irrelevant lymphocytes on adoptive transferred experimental allergic encephalomyelitis

To help understand effector mechanisms in experimental allergic encephalomyelitis (EAE) we examined the effects of adding ‘irrelevant’ lymphocytes from non-EAE donors to major basic protein (MBP)-reactive lymphocytes in the adoptive transfer of EAE (Tr-EAE). The intravenous injection of tentanus toxoid-reactive lymphocytes (TT-cells) and phytohemagglutinin-stimulated lymphocytes on the same day or 2 days after intra-arterial injection of MBP-reactive lymphocytes enhanced the clinical and pathological expression of Tr-EAE. In lymphocyte trafficking studies there was significant accumulation of these injected TT-cells in the central nervous system during enhanced transfer of EAE. W3/25-positive cells were much more predominant in lesion of central nervous system when reinjected with TT cells along with MBP cells compared with lesions of rats injected with MBP cells alone. These findings suggest possible participation of lymphocytes other than MBP-reactive cells in the expression of EAE and provide a useful model to further explore effector mechanism in the future.

Experimental allergic encephalomyelitis in the absence of a classical delayed-type hypersensitivity reaction. Severe paralytic disease correlates with the presence of interleukin 2 receptor-positive cells infiltrating the central nervous system.

One characteristic of experimental allergic encephalomyelitis (EAE) in all species is the presence of a considerable leukocyte infiltrate in the central nervous system (CNS). By adoptive transfer of EAE into irradiated or nonirradiated Lewis strain rats we now show that the bulk (greater than 90%) of infiltrating cells in the CNS are superfluous to the induction of disease, as lethally irradiated recipients, despite having very few infiltrating cells in the CNS, acquire severe paralytic EAE. The reduction in the level of infiltration in irradiated recipients is selective, however, as both irradiated and nonirradiated diseased animals have very similar numbers of cells expressing IL-2-R. Disease in irradiated recipient animals is associated with substantial submeningeal hemorrhage in the spinal cord and brain stem and similar hemorrhages are found in recipients rendered leukopenic with cytotoxic drugs. Clinical signs of disease and hemorrhage are preventable, however, by administration to the recipient rats of mAbs specific for the CD4 antigen. Classic delayed-type hypersensitivity (DTH) reactions are transferable with the same cells that produce EAE in both irradiated and nonirradiated recipient rats, but such transfer of DTH is observed only in nonirradiated recipient animals and not in irradiated rats. Collectively, the findings reported herein support the conclusion that the paralysis characteristic of acute EAE is mediated by the direct action of very small numbers of activated CD4+ lymphocytes that infiltrate the CNS and produce their effects by inducing vascular damage. The findings are not consistent with reports that the lesions in EAE are produced by a classic DTH reaction.

The immunopathology of adoptively transferred experimental allergic encephalomyelitis (EAE) in Lewis rats: Part 1. Immunohistochemical examination of developing lesions of EAE

In order to examine developing lesions of experimental allergic encephalomyelitis (EAE) at the preclinical stage, adoptive transfer of EAE was achieved in Lewis rats using spleen cells obtained from rats previously immunized with 50 μg of guinea pig myelin basic protein (MBP) in complete Freund's adjuvant. After cell transfer, all the recipient rats developed severe paraparesis with minimal variation in the onset of clinical signs, which facilitated immunohistochemical examination of developing lesions of EAE in asymptomatic animals. The initial pathological finding detected in this system was an increased number of inflammatory cells (both OX19 + and OX8 + T cells and macrophages) in the subarachnoid space (SAS) which was observed on day 3 post-transfer (PT) when the recipient animals showed no neurological abnormalities. By day 4 PT, inflammatory cells were detected in the Virchow-Robin space of vessels which were continuous to the SAS. Perivascular lymphocytic infiltration was scarcely detected in the gray matter. On day 5 PT, the rats showed severe paraparesis. Inflammatory foci increased in number and were detected in both the white and gray matter. Diffuse parenchymal T-lymphocyte infiltration was also recognized at this stage. From day 6 PT onwards, inflammatory cells decreased gradually. On day 8 PT, all the rats recovered from EAE and few inflammatory cells were detected in the parenchyma and SAS. Immunohistochemical examination of T-cell subsets and Ia antigens revealed that (1) the number of OX19 + cells was greater than that of OX8 + cells in the parenchyma and SAS at all stages examined, (2) the distribution of OX19 + cells was almost the same as that of OX8 + cells, (3) OX8 + cells decreased in number before clinical signs subsided, and that (4) after the infiltration of T cells into the parenchyma, cells with dendritic morphology (microglia) expressed Ia antigens in close association with the infiltrating T cells. Adoptive transfer of MBP-sensitized spleen cells provides constant induction of EAE with minimal variation in clinical onset and severity, thus being a useful model for the examination of early events of EAE.

Failure of serum from recovered rats to prevent enhanced adoptive transfer of experimental allergic encephalomyelitis

The rat is unique among species used for research on experimental allergic encephalomyelitis (EAE) because of the spontaneous recovery which occurs routinely after severe, almost fatal disease. The mechanism of recovery has never been adequately explained although it has been suggested that suppressor cells might play a role in this phenomenon. In another immune system (contact sensitivity) anti-idiotypic antibodies obtained during the recovery phase have been shown to have a protective effect. Adoptive transfer of EAE, which can be markedly enhanced by incubation of sensitized cells with antigen in vitro, offers a convenient tool for investigating mechanisms of recovery. With this system, we have attempted to suppress transfer of disease with serum obtained from recovered rats. In spite of various manipulations of the experimental protocol, including the use of serum plus complement before and after incubation of cells with antigen, we have been unable to demonstrate suppression of disease. We and others recently reported that cells from recovered rats are also capable of enhanced transfer. This permitted the use of autologous serum from individual cell donors. Even in this strictly autologous system, however, no inhibitory effect of serum could be detected.