Expression of CD45RC and Ia antigen in the spinal cord in acute experimental allergic encephalomyelitis: An immunocytochemical and flow cytometric study

Abstract

We performed immunocytochemical studies to analyze the inflammatory infiltrate and major histocompatibility complex class II (Ia) antigen expression in the spinal cord of Lewis rats with acute experimental allergic encephalomyelitis (EAE) induced by inoculation with myelin basic protein and adjuvants. Using antibodies to lymphocyte markers and other monoclonal antibodies we found that during clinical episodes the inflammatory infiltrate was chiefly composed of T lymphocytes and macrophages. The majority of cells in the inflammatory infiltrate were stained by the W3/25 antibody to CD4 and a proportion was stained by OX22 which labels the high molecular weight form of the leucocyte common antigen (CD45RC). CDB+ T cells were sparse and B cells were not detected. There was minimal staining with the OX39 antibody to the interleukin-2 receptor. Presumptive microglia, identified by their dendritic morphology, expressed Ia antigen during the clinical episodes and after recovery. The prominence of Ia antigen expression after recovery could indicate that this la expression was associated with downregulation of the encephalitogenic immune response. We also performed flow cytometry studies on cells extracted from the spinal cord of rats before and during attacks of EAE. With flow cytometry, we found that in established disease a mean of 83(SD, 23)% of CD2+ cells were CD4+, and a mean of 27(SD, 12)% of CD2+ cells were CD45RC+. In rats sampled on the first day of signs, a mean of 43(SD, 22)% of CD2+ cells were CD45RC+. In the cells extracted from the spinal cord of rats with established disease a mean of 47(SD, 32)% of macrophages were CD45RC+. Our study has combined an immunocytochemical assessment of tissue sections with quantitative flow cytometry assessment of cells extracted from the spinal cord of rats with acute EAE. We have shown that the majority of T lymphocytes in the spinal cord are CD45RC − . We have also found prominent Ia expression on dendritic cells in acute EAE and after clinical recovery.

Inflammatory cells, microglia and MHC class II antigen-positive cells in the spinal cord of Lewis rats with acute and chronic relapsing experimental autoimmune encephalomyelitis

“…In the later episodes of CR-EAE, prominent Ia expression on cells of dendritic morphology was observed with immunocytochemistry, and increased numbers of Ia + cells, including FSC low cells typical of microglia, were found with flow cytometry. In the CNS, Ia can be expressed on infiltrating lymphocytes, macrophages and microglia and has been widely described in acute EAE (Matsumoto et al, 1986;Vass et al, 1986;Konno et al, 1989;McCombe et al, 1992). In this model of CR-EAE, widespread Ia expression in the CNS was found 50 days after inoculation (Polman et al, 1988).…”

“…In rats with acute EAE induced by inoculation with whole CNS tissue or MBP, the majority of the T cells in the spinal cord are CD4 + CD45RC McCombe et al, 1992). In mice with acute EAE induced by the passive transfer of labelled, MBP-sensitized lymph node cells, the labelled cells in the CNS are CD45RB low (equivalent to our CD45RC − ) (Zeine and Owens, 1992).…”

Corticosteroid treatment of experimental autoimmune encephalomyelitis in the Lewis rat results in loss of Vβ8.2+ and myelin basic protein-reactive cells from the spinal cord, with increased total T-cell apoptosis but reduced apoptosis of Vβ8.2+ cells

“…The development of EAE in Lewis rats is associated with infiltration of the nervous system by T-lymphocytes and macrophages (Hickey et al, 1983;McCombe et al, 1992), followed by demyelination of the central nervous system and the nerve roots. We have recently shown that recovery from passively transferred and actively induced MBP-EAE is associated with a selective elimination of V 8.2 + MBP-reactive T-cells from the spinal cord by apoptosis (Tabi et al, 1994 andTabi et al, 1995;McCombe et al, 1996) and have suggested that this apoptosis may represent activation-induced cell death of T-lymphocytes in the target organ of this autoimmune disease Tabi et al, 1994 andTabi et al, 1995).…”

“…EAE is the best available animal model of multiple sclerosis. Recovery from EAE is associated with loss of T-lymphocytes from the central nervous system (CNS) (Matsumoto and Fujiwara, 1987;McCombe et al, 1992;Zeine and Owens, 1993) and apoptosis of these lymphocytes in the CNS (Pender et al, 1991 andPender et al, 1992;Schmied et al, 1993). In the Lewis rat, the encephalitogenic lymphocytes in EAE induced by inoculation with myelin basic protein (MBP) (MBP-EAE) are predominantly V 8.2 + (Offner et al, 1993;Tsuchida et al, 1993;Imrich et al, 1995).…”

Cytokine expression by inflammatory cells obtained from the spinal cords of Lewis rats with experimental autoimmune encephalomyelitis induced by inoculation with myelin basic protein and adjuvants

“…It can be induced by inoculation with myelin proteins, such as myelin basic protein (MBP), and adjuvants and can be passively transferred to naive animals by CD4 + T cells (Pettinelli and McFarlin, 1981). EAE is characterized by infiltration of the nervous system with activated T lymphocytes and macrophages (Raine, 1984;McCombe et al, 1992). Cloned encephalitogenic T cells secrete interleukin-2 (IL-2) and interferon-(IFN-) (Ando et al, 1989;Baron et al, 1993).…”