Vincent K. Tuohy

Acute Experimental Allergic Encephalomyelitis in SJL/J Mice Induced by a Synthetic Peptide of Myelin Proteolipid Protein

Clinical, histologic, and ultrastructural characteristics of acute experimental allergic encephalomyelitis (EAE) induced by sensitization with a synthetic peptide corresponding to mouse myelin proteolipid protein (PLP) residues 139-151 HCLGKWLGHPDKF were studied in SJL/J mice. Groups of mice were immunized with 20, 50, or 100 nmol of the peptide and were killed from seven to 28 days after sensitization or when they were moribund. Beginning on Day 9, the mice showed signs of EAE and the disease progressed rapidly to paralysis. Central nervous system (CNS) inflammation, edema, gliosis, and demyelination were found in all mice killed between Days 10 and 28 and white matter lesion areas correlated with clinical score at the time the mice were killed. Peripheral nerve roots and the cauda equina did not have lesions. Within the range studied, the severity of clincal or histologic disease was the same regardless of the PLP peptide dose. Two often mice immunized with 100 nmol and none of 14 mice given smaller doses of a synthetic peptide of mouse myelin basic protein (MBP) showed clinical EAE. These mice had small numbers of CNS lesions that were indistinguishable from those in PLP peptide-sensitized mice. These findings demonstrate that immunization of SJL/J mice with PLP peptide 139— 151 produces a disease with the clinical and morphologic features of CNS tissue-, whole PLP-, whole MBP-, and MBP peptide-induced acute EAE. Thus, PLP is a major encephalitogen and immune reactions to epitopes of different myelin proteins may induce identical patterns of injury in the CNS.

Myelin proteolipid protein: minimum sequence requirements for active induction of autoimmune encephalomyelitis in SWR/J and SJL/J mice ☆

Proteolipid protein (PLP) is the major protein constituent of mammalian central nervous system myelin. We have previously identified two different PLP encephalitogenic T cell epitopes in two mouse strains. Murine PLP peptides 103-116 YKTTICGKGLSATV and 139-151 HCLGKWLGHPDKF are encephalitogenic determinants in SWR/J (H-2q) and SJL/J (H-2s) mice, respectively. The purpose of the present study was to determine the minimum sequence requirements for each of these PLP encephalitogens. In SWR/J mice, at least two distinct overlapping peptides can induce experimental autoimmune encephalomyelitis (EAE). The eleven residue sequences PLP 105-115 TTICGKGLSAT and PLP 106-116 TICGKGLSATV are encephalitogenic in SWR/J mice, but PLP 106-115 TICGKGLSAT, the decapeptide indigenous to both sequences, is non-encephalitogenic. In contrast, the shortest PLP sequence capable of inducing EAE in SJL/J mice is the nonapeptide 141-149 LGKWLGHPD. These data indicate that encephalitogenic determinants of PLP are short contiguous peptide sequences similar in length and diversity to those of MBP.

Lower urinary tract phenotype of experimental autoimmune cystitis in mouse: a potential animal model for interstitial cystitis.

To examine bladder function in a newly developed experimental autoimmune cystitis (EAC) model in female SWXJ strain mice, as a potential animal model for interstitial cystitis (IC).

Sodium Stibogluconate Interacts with IL-2 in Anti-Renca Tumor Action via a T Cell-Dependent Mechanism in Connection with Induction of Tumor-Infiltrating Macrophages

IL-2 therapy results in 10–20% response rates in advanced renal cell carcinoma (RCC) via activating immune cells, in which the protein tyrosine phosphatase Src homology 2 domain-containing phosphatase 1 (SHP-1) is a key negative regulator. Based on finding that sodium stibogluconate (SSG) inhibited SHP-1, the anti-RCC potential and action mechanism of SSG and SSG/IL-2 in combination were investigated in a murine renal cancer model (Renca). Despite its failure to inhibit Renca cell proliferation in cultures, SSG induced 61% growth inhibition of Renca tumors in BALB/c mice coincident with an increase (2-fold) in tumor-infiltrating macrophages (Mφ). A combination of SSG and IL-2 was more effective in inhibiting tumor growth (91%) and inducing tumor-infiltrating Mφ (4-fold), whereas IL-2 alone had little effect. Mφ increases were also detected in the spleens of mice treated with SSG (3-fold) or SSG/IL-2 in combination (6-fold), suggesting a systemic Mφ expansion similar to those in SHP-deficient mice. T cell involvement in the anti-Renca tumor action of the combination was suggested by the observations that the treatment induced spleen IFN-γ T cells in BALB/c mice, but failed to inhibit Renca tumor growth in athymic nude mice and that SSG treatment of T cells in vitro increased production of IFN-γ capable of activating tumoricidal Mφ. The SSG and SSG/IL-2 combination treatments were tolerated in the mice. These results together demonstrate an anti-Renca tumor activity of SSG that was enhanced in combination with IL-2 and functions via a T cell-dependent mechanism with increased IFN-γ production and expansion/activation of Mφ. Our findings suggest that SSG might improve anti-RCC efficacy of IL-2 therapy by enhancing antitumor immunity.

A Novel Class II-Binding Motif Selects Peptides That Mediate Organ-Specific Autoimmune Disease in SWXJ, SJL/J, and SWR/J Mice

Idiopathic dilated cardiomyopathy (DCM) is responsible for ∼25% of all cases of congestive heart failure. We have recently shown that immunization of autoimmune-susceptible SWXJ mice with whole cardiac myosin leads to T cell-mediated experimental autoimmune myocarditis (EAMC) and DCM. We have now identified two disease-inducing peptides from cardiac α-myosin heavy chain (CAMHC). Our approach involved the use of a novel MHC class II-binding motif contained in several peptides known to be immunogenic in SWXJ (H-2q,s) mice or in the parental SJL/J (H-2s) or SWR/J (H-2q) mouse strains. Two of four CAMHC peptides containing the -KXXS- peptide motif were found to be immunogenic. Immunization of SWXJ or parental SJL/J and SWR/J mice with CAMHC peptides pα406–425 or pα1631–1650 resulted in EAMC and DCM, characterized by inflammation, fibrosis, and decompensated right-sided ventricular dilatation. Despite mediating high incidences of severe disease, both peptides were found to be cryptic determinants, thereby providing further evidence for the importance and perhaps predominance of self crypticity in autoimmunity. Both peptides showed dual parental I-Aq and I-As restriction and mediated passive transfer of disease with activated CD4+ T cells. An intact motif was necessary for antigenicity because loss of activity occurred in peptides containing nonconservative substitutions at the motif’s terminal lysine and serine residues. Our studies provide a new model for EAMC and DCM in strains of mice widely used in autoimmune studies. Moreover, the -KXXS- motif may be particularly useful in implicating previously overlooked proteins as autoimmune targets and in facilitating the development of new organ-specific autoimmune mouse models for human diseases.

EAE induced by myelin proteolipid apoprotein (PLP) in various strains of mice

Multiple sclerosis is considered to be an autoimmune demyelinating disease of the central nervous system. The cause of MS is unknown but there is much circumstantial evidence that immunological factors are involved, including the resemblance between this disease and its laboratory model, experimental allergic encephalomyelitis induced by immunization with myelin bas~c protein. Despite the similarities, however, there are also major differences which prevent EAE from being accepted as the experimental counterpart of MS. The mechanisms involved in MS are unknown but, since the blood-brain barrier is damaged, injury to endothelial cells is likely to have occurred. We report here the results of immune-mediated damage to these cells, produced by immunizing guinea pigs and rhesus monkeys with a membrane fraction obtained from cerebral endothelial cells grown in vitro. The inoculum was free from myelin basic protein. The immunized animals developed a neurological illness. Histological examination showed large areas of demyelination, especially in the periventricular region, were present. These lesions bore a striking similarity to the brain in MS. The new animal model described may prove to useful in the investigation of human demyelinating disease.

Autoimmune-mediated inner ear inflammation in mice immunized with coch-5B2

Abstract Problem: We have shown that SWXJ mice develop hearing loss when immunized with the p131–150 peptide of Coch-5B2 or following transfer of activated T cells specific for the Coch 131–150 peptide. Further studies to establish associated histopathology in the cochleas of these mice were pursued in this paper. Methods: Mice were immunized with Coch 131–150 in complete Freund’s adjuvant (CFA) and euthanized 2–5 weeks later. Inner ear tissues were immunostained for detection of inflammatory cells. ABR testing to determine hearing thresholds was performed on Coch 131–150 primed mice and on age- and sex-matched control mice immunized with CFA only. Results: Inner ear inflammation was observed 5 weeks after active immunization with Coch 131–150, but not at 2, 3, or 4 weeks. Increased ABR thresholds were accompanied by substantial CD45+ immunostaining in the lower spiral ligament primarily in the high frequency region of the cochlea. Control animals showed no increase in ABR thresholds and no inner ear inflammation. Conclusion: Induction of experimental autoimmune hearing loss in mice by immunization with Coch 131–150 results in appearance of leukocytes in the inner ear. The current data support our previously reported findings that Coch-5B2 targets T cell-mediated hearing loss in SWXJ mice. Significance: Our study shows that T cells targeted against inner ear-specific antigens may mediate inner ear inflammation and hearing loss in the mouse similar to that observed in human autoimmune sensorineural hearing loss (ASNHL). Thus, our study supports a critical role of autoreactive T cells in ASNHL and provides a contemporary mouse model for evaluating new treatment strategies. Support: Grants from the Deafness Research Foundation, the Samuel Rosenthal Foundation, the Triple T Foundation, the Milton and Charlotte Kramer Foundation, and NIH NS-36054.