Rodriguez, Moses

Abstract Intracerebral inoculation of mice with Theiler's murine encephalomyelitis virus results in an intense inflammatory response of mononuclear leukocytes which infiltrate into the central nervous system. Resistant strains of mice have the ability to clear virus whereas susceptible strains become infected persistently and are associated with chronic demyelination which is proposed to be immune-mediated. In an attempt to better understand the role of the immune response during demyelination, mononuclear leukocytes were isolated from the central nervous system of infected mice and stained by an immunoperoxidase technique with anti-Thy-1.2, anti-L3T4, anti-Lyt-2 and anti-MAC-1 mAb. Infection of susceptible SJL/J mice resulted in a biphasic immune response which peaked on days 7 and 27 post-infection. In contrast, a single peak (day 7) was observed in resistant C57BL/10SNJ mice. The presence of Thy-1.2, L3T4, and MAC-1+ cells was similar between the two strains. However, although the number of Lyt-2+ cells peaked on day 7 in C57BL/10SNJ mice, they were not detected in SJL/J mice until 14 days post-infection and gradually increased in number over the course of infection. To further study the role of T cells in demyelination, serial frozen sections of brain and spinal cord were stained for the presence of Lyt-2 and L3T4+ cells in the lesions of chronically infected SJL/J mice. L3T4+ cells were observed predominantly in perivascular regions while Lyt-2+ cells were observed infiltrating the parenchyma. These results provide further evidence that Lyt-2+ lymphocytes are important in the mechanism of susceptibility/resistance to Theiler's murine encephalomyelitis virus-induced demyelination.

Abstract Demyelination induced by Theiler's virus was examined in nonrecombinant H-2 congeneic strains of mice on common backgrounds expressing independent haplotypes. Light and electron microscopy of spinal cord sections from mice with s, f, p, r, v, or q haplotypes on a C57BL/10 background showed perivascular inflammation and multifocal areas of demyelination in the white matter. The demyelination in these mice was usually associated with clinical neurologic deficits. In contrast, mice with identical genetic backgrounds but b, k, or d haplotypes showed no pathologic or clinical abnormalities. Qa or Tla haplotypes did not appear to influence demyelination. The observations support the hypothesis that susceptibility to Theiler's murine encephalomyelitis virus-induced demyelination is influenced by genes that are linked to the H-2 complex. The findings suggest that the demyelination may be mediated by immune cells rather than being a direct cytolytic effect of virus on oligodendrocytes.

Abstract Mice bearing the autosomal recessive gene "wasted" (wst/wst) have been reported to develop low or absent secretory immune responses, abnormal DNA repair mechanisms, and uncoordinated body movements. We have performed a detailed immunologic and neuropathologic investigation of the disease. Con A and LPS mitogenic responses of splenic lymphocytes as well as total serum Ig levels were equivalent in wst/wst and undiseased control littermates (wst/+ and +/+). Amounts of serum IgM, IgG2a, IgG2b, IgG3, and IgA, however, were reduced in wst/wst animals. FACS analyses of Ig+ and isotype-specific B cell populations revealed similar percentages of Ig+, mu +, gamma +, and alpha + cells in wst/wst and control mice. However, the percentage of "very bright" Ig+ cells as well as "very bright" heavy and light chain-specific B cell subpopulations was increased at least 10-fold in wst/wst B cells as compared with littermate controls. In addition, studies of Ig-specific mRNA accumulation in these animals revealed significant decreases in all isotypes except gamma 3 in spleens of wst/wst mice as compared with littermate controls. Neuropathologic studies in wst/wst mice showed prominent vacuolar degeneration of neurons within anterior horns of the spinal cord and the motor nuclei of the brain stem. No abnormalities were noted in Purkinje cells of the cerebellum nor within myelin sheaths. The abnormalities in the nervous system resembled human motor neuron disease rather than ataxia-telangiectasia as had been reported previously. The immunologic studies suggest that splenic B cells from wst/wst mice have a defect in the ability to "switch" from membrane to secreted Ig. In addition, this mutation provides a mechanism to study regulatory interactions between the immune and nervous systems.

Abstract Theiler's murine encephalomyelitis virus induced central nervous system demyelination in susceptible strains of mice with s, q, v, p, and f H-2D alleles. We used immunoelectron microscopy to look for differential production of class II immune response gene products (Ia) within astrocytes, oligodendrocytes, microglia, and endothelial cells. Spinal cord sections from susceptible mice (B10.S and B10.ASR2) showed increased content of Ia in glial and endothelial cells. In contrast, resistant mice [B10.S(9R)] showed minimal Ia production within the CNS. The findings indicate an important role of class II immune response products on glial cells during demyelination after virus infection.

Abstract Intracerebral infection of certain strains of mice with Theiler’s virus results in chronic immune-mediated demyelination in spinal cord. We used mouse mutants with deletion of the V beta class of TCR genes to examine the role of TCR genes in this demyelinating disease which is similar to multiple sclerosis. Quantitative analysis of spinal cord lesions demonstrated a markedly increased number and extent of demyelinated lesions in persistently infected RIII S/J mice which have a massive deletion of the TCR V beta-chain (V beta 5.2, V beta 8.3, V beta 5.1, V beta 8.2, V beta 5.3, V beta 8.1, V beta 13, V beta 12, V beta 11, V beta 9, V beta 6, V beta 15, V beta 17) compared with B10.RIII mice which are of identical MHC haplotype (H-2r) but have normal complement of V beta TCR genes. In contrast, infection of C57L (H-2b) or C57BR (H-2k) mice which have deletion of the V beta TCR genes (V beta 5.2, V beta 8.3, V beta 5.1, V beta 8.2, V beta 5.3, V beta 8.1, V beta 13, V beta 12, V beta 11, and V beta 9) resulted in few demyelinating lesions. Genetic segregation analysis of (B10.RIII x RIII S/J) x RIII S/J backcrossed mice and (B10.RIII x RIII S/J) F2 mice demonstrated correlation of increased susceptibility to demyelination with deletion of TCR V beta genes. The increase in number of demyelinating lesions correlated with increase in number of virus-Ag+ cells in spinal cord. These experiments provide strong evidence that the structural diversity at the TCR beta-complex can influence susceptibility to virus-induced demyelination.

Abstract The effects of therapy with mAb to T cell subsets were studied in mice with Theiler's murine encephalomyelitis virus-induced demyelination. mAb GK1.5 (directed at class II-restricted T cells) and mAb 2.43 (directed at class I-restricted T cells) depleted the appropriate subset of T cells in lymph nodes, spleens, and peripheral blood for 6 to 8 wk after a single i.p. injection of 1 mg of purified mAb. Early treatment with mAb GK1.5 (days -1, 0, and +1 relative to virus injection) resulted in death, encephalitis, and increased demyelination in the majority of animals tested. Treatment with mAb 2.43 resulted in less meningeal inflammation and fewer demyelinating lesions in the spinal cord, irrespective of whether the mAb was given early or after demyelinating disease was established (days 15, 16, and 17). Beneficial response to mAb therapy did not correlate with titers of virus isolated from the central nervous system or serum. These results indicate an important role of class II-restricted T cells during early disease in preventing overwhelming encephalitis; class I-restricted T cells may be critical during demyelination.

Abstract Intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) produces chronic demyelination and persistent infection in the central nervous system (CNS) of susceptible SJL mice. This series of experiments examined the contribution of humoral immunity and C to myelin destruction. As in multiple sclerosis, mice persistently infected with TMEV had elevated levels of IgG and oligoclonal bands in the cerebrospinal fluid (CSF). Immunoblot studies revealed that even in animals exhibiting profound demyelination, IgG in the serum and CSF was directed primarily at virus antigen rather than at normal myelin components. Inflammatory cells positive for Ig were distributed mainly around blood vessels, but occasionally they infiltrated the spinal cord parenchyma. Rare examples of myelin sheaths positive for IgG were found by immunoelectron microscopy in spinal cord sections from infected mice; the third component of complement (C3) was commonly found in the walls of CNS blood vessels but not on myelin. Neither serum nor CSF IgG from infected mice bound to myelin sheaths or other CNS components in sections of normal syngeneic spinal cord. There were significantly more demyelinating lesions in infected mice depleted of C components with cobra venom factor. These data do not support a humoral autoimmune basis for the CNS demyelination that occurs in association with persistent TMEV infection. However, the humoral immune response directed at TMEV antigens may either limit virus spread or promote virus persistence.

Abstract MS is an autoimmune disease of the CNS and among all the genetic factors; MHC class-II molecules show the strongest association. To better understand the role of MHC class-II (HLA-DR/DQ) genes in susceptibility and resistance to MS, we utilized transgenic (Tg) mice expressing HLA class-II gene lacking endogenous mouse class II genes. HLA-DR3 Tg mice are susceptible to PLP91-110 induced experimental autoimmune encephalomyelitis (EAE), whereas DQ8 (DQB1*0302) transgenic mice are resistant. To identify the gene expression changes and pathways required for disease susceptibility vs resistance to EAE, we performed mRNA expression profiling of CD4+ T cells from HLA-DR3 (susceptible) and HLA-DQ8 (resistant) Tg mice. Whole genome expression analysis identified 2945 genes in HLA-DR3 Tg mice (PLP91-110 immunized vs. naïve) and 1053 genes in HLA-DQ8 Tg mice (PLP91-110 immunized vs. naïve). Comparison of modulated genes between DR3 and DQ8 identified 772 genes common to both strains, 2173 genes unique to DR3 whereas 281 genes were unique to DQ8 mice. Ingenuity pathway analysis showed up regulation of pathways involved in T cell signaling in inflammation, NF-kB signaling and those responsible for communication between innate and adoptive immunity. Majority of these pathways have IL1β as a major upstream regulator in disease susceptible HLA-DR3 Tg mice. Thus microarray data indicates an important role of IL1β induced encephalitogenic T helper cell differentiation in disease susceptibility.

Objective: Cognitive involvement in pediatric multiple sclerosis (MS) relative to adult MS is less defined. This study advances our understanding by measuring cognitive performances in pediatric MS, adult MS, and pediatric healthy controls. Methods: Consecutive relapsing pediatric MS participants from the United States Network of Pediatric MS Centers were compared with pediatric healthy controls and adults with relapsing MS. Participants were compared on two screening batteries: the Brief International Cognitive Assessment for MS and the Cogstate Brief Battery. Results were transformed to age-normative z scores. Results: The pediatric groups (MS vs. Healthy Controls) did not differ on either battery’s composite mean score or individual test scores ( ps > 0.32), nor in the proportions impaired on either battery, Brief International Cognitive Assessment for MS (26% vs. 24%, p = 0.83); Cogstate Brief Battery (26% vs. 32%, p = 0.41). The pediatric versus adult MS group even after controlling for differences in disease duration performed better on the Brief International Cognition Assessment for MS composite ( p = 0.03), Symbol Digit Modalities Test ( p = 0.02), Rey Auditory Verbal Learning Test ( p = 0.01), and Cogstate choice reaction time ( p < 0.001). Conclusion: Pediatric MS patients do not differ from healthy pediatric controls on cognitive screens but perform better than adults with MS.

Objective The purpose of this study was to determine the frequency of myelin oligodendrocyte glycoprotein (MOG)‐IgG and aquaporin‐4 (AQP4)‐IgG among patients with pediatric‐onset multiple sclerosis (POMS) and healthy controls, to determine whether seropositive cases fulfilled their respective diagnostic criteria, to compare characteristics and outcomes in children with POMS versus MOG‐IgG‐associated disease (MOGAD), and identify clinical features associated with final diagnosis. Methods Patients with POMS and healthy controls were enrolled at 14 US sites through a prospective case–control study on POMS risk factors. Serum AQP4‐IgG and MOG‐IgG were assessed using live cell‐based assays. Results AQP4‐IgG was negative among all 1,196 participants, 493 with POMS and 703 healthy controls. MOG‐IgG was positive in 30 of 493 cases (6%) and zero controls. Twenty‐five of 30 patients positive with MOG‐IgG (83%) had MOGAD, whereas 5 of 30 (17%) maintained a diagnosis of multiple sclerosis (MS) on re‐review of records. MOGAD cases were more commonly in female patients (21/25 [84%] vs 301/468 [64%]; p = 0.044), younger age (mean = 8.2 ± 4.2 vs 14.7 ± 2.6 years; p < 0.001), more commonly had initial optic nerve symptoms (16/25 [64%] vs 129/391 [33%]; p = 0.002), or acute disseminated encephalomyelitis (ADEM; 8/25 [32%] vs 9/468 [2%]; p < 0.001), and less commonly had initial spinal cord symptoms (3/20 [15%] vs 194/381 [51%]; p = 0.002), serum Epstein–Barr virus (EBV) positivity (11/25 [44%] vs 445/468 [95%]; p < 0.001), or cerebrospinal fluid oligoclonal bands (5/25 [20%] vs 243/352 [69%]; p < 0.001). Interpretation MOG‐IgG and AQP4‐IgG were not identified among healthy controls confirming their high specificity for pediatric central nervous system (CNS) demyelinating disease. Five percent of those with prior POMS diagnoses ultimately had MOGAD; and none had AQP4‐IgG positivity. Clinical features associated with a final diagnosis of MOGAD in those with suspected MS included initial ADEM phenotype, younger age at disease onset, and lack of EBV exposure. ANN NEUROL 2023;93:271–284