Cynthia Webb

Suppression of experimental allergic encephalomyelitis in rhesus monkeys by a synthetic basic copolymer

Abstract Experiments with rhesus monkeys demonstrate that a random basic copolymer of amino acids, denoted Cop 1, suppresses experimental allergic encephalomyelitis (EAE) when administered to the animals after clinical symptoms have already appeared. Fifteen daily injection of this material caused reversal of disease symptoms in the two treated monkeys, one of which suffered relapse 38 days later. When no treatment was given, the control monkeys deteriorated rapidly and died within a short time after onset of symptoms. Histological tests indicate EAE lesions in the brains of all monkeys except the monkey saved by Cop 1.

Onset of endogenous synthesis of epidermal growth factor in neonatal mice.

We have analyzed mouse fetuses and neonates for the presence of epidermal growth factor (EGF)-specific mRNA. No detectable EGF-specific mRNA was found in fetuses, fetal membranes, or placentae from Day 9 of gestation through birth or in the early neonatal period. While the kidneys begin to produce EGF specific transcripts by two weeks postpartum, the salivary glands begin to produce detectable levels of EGF mRNA only after weaning and even then at levels far below the adult amount. Reports of EGF and EGF-related material in rodent fetuses failed to determine whether this material was of maternal or fetal origin. We now conclude that authentic EGF in these embryos is probably of maternal origin. We have performed experiments designed to determine whether EGF can be transported into the fetus. A small percentage of 125I-EGF administered to pregnant females either systemically or directly into the uterine arteries reached the fetus itself. The uterus and the placenta attained a high level of labeling, whereas the amniotic fluid and yolk sac were virtually devoid of the tracer. In the neonatal period, milk may be the physiologically relevant source of EGF. We have found that 125I-EGF ingested by neonates was absorbed into the circulation, reached many internal organs, and was eventually excreted in the urine. Previously demonstrated EGF receptors in mouse embryonic cell types may be activated by either alpha type transforming growth factor or maternal EGF transported via the placenta.

Molecular requirements involved in suppression of eae by synthetic basic copolymers of amino acids

Abstract A survey was carried out in order to characterize the molecular requirements involved in suppression of experimental allergic encephalomyelitis (EAE∗) by synthetic basic copolymers. A copolymer identical in composition to the most active suppressive copolymer (denoted Cop 1) was prepared from amino acids of D configuration. This material has no suppressive effect on EAE thus eliminating the possibility that the biological activity of the copolymers is due to their basicity either as regards net electrical charge or distribution of the charge on the molecule. On the other hand, a related copolymer in which tryptophan replaces tyrosine (Cop 4) was very effective in disease suppression. Cop 4 manifests at least the same extent of cross-reactivity with the natural encephalitogen as Cop 1, both in vivo and in vitro, whereas D -Cop 1 is not cross-reactive. These findings support the hypothesis that immunological mechanisms are involved in the suppressive phenomenon.

Cellular immune response to peripheral nerve basic protein in idiopathic facial paralysis (Bell's palsy).

Lymphocytes from patients with Bells palsy were shown to undergo significant stimulation when cultured in vitro in the presence of a purely neuritogenic basic protein (P1L) isolated from human peripheral nerve myelin. No sensitization was observed to other neural antigens, namely, another periperal nerve myelin basic protein (P2) and the central nerve myelin basic encephalitogenic protein (BE). A similar pattern of response was also demonstrated in patients with Guillain-Barré syndrome (GBS). Lymphocytes from patients suffering from other neuropathies or other diseases involving the face showed no response to any of these antigens. The specific in vitro response to P1L protein in Bells palsy may suggest that an in vivo sensitization of lymphocytes to such self protein occurs in this condition, and that cell-mediated, probably post-infectious, autoimmune mechanisms may be an important factor in the pathogenesis of the paralysis. Thus, Bells palsy is immunologically similar to GBS, or may even represent a mononeuritic variant of GBS. In view of these findings the administration of steroids to patients with Bells palsy seems logical on the basis of their immunosuppressive action.

Cell‐mediated immunity to neural antigens in idiopathic polyneuritis and myeloradiculitis: Clinical‐immunologic classification of several autoimmune demyelinating disorders

Patients with peripheral nervous system disorders were tested for the presence of cellular hypersensitivity to peripheral and central nervous system antigens by means of the in vitro lymphocyte transformation technique. Lymphocytes sensitized to the neuritogenic peripheral nervous system P1L basic protein were found in pure polyradiculitis of the Guillain-Barré syndrome type. Lymphocytes from patients with myeloradiculitis underwent transformation by peripheral P2 basic protein and by central nervous system basic encephalitogenic protein. In cases of chronic relapsing polyneuropathy response was shown to the central nervous system basic encephalitogen and to both of the peripheral nerve basic proteins. Lymphocytes from patients with other neurologic conditions showed no response to any of these antigens. These findings suggest that cell mediated immunity to specific basic proteins of the myelin plays a role in the pathogenesis of the above-mentioned demyelinating disorders and may lead to a new approach in their classification and diagnosis.

Developmental potential of myeloid leukemia cells injected into midgestation embryos

Cells from a clone of mouse myeloid leukemic cells that can be induced to differentiate in vitro to mature cells by the normal macrophage- and granulocyte-inducing protein, MGI-2, were injected into mouse embryos at 10 days gestation. The leukemic cells, derived from an SJL/J mouse, were microinjected into the placentae of C3HeB fetuses and the viable progeny were tested for chimerism by analysis of glucose phosphate isomerase isozymes. Fifty-five percent out of 201 viable progeny died prior to weaning due to tumors derived from the injected cells. Of the remaining 91 apparently healthy adult animals, 2 had chimeric populations. One mouse had a chimeric population of granulocytes and the other mouse a chimeric population of macrophages. The animal with a chimeric population of macrophages was chimeric at 1 and 2 months of age and had lost any detectable donor derived contribution by the age of 3 months. The chimeric granulocyte population in the other animal was still stable at 3 months. The myeloid leukemic cells injected into midgestation embryos thus participated in the development of two different cell types in apparently healthy adult animals. Our results indicate that malignant cells of more restricted developmental potential than teratocarcinoma cells may participate in normal development. It remains to be determined whether this participation in normal development was due to normal differentiation of the malignant cells, or the production of nonmalignant segregants derived from the malignant cells.

Neuritogenic and Encephalitogenic Properties of the Peripheral Nerve Basic Proteins

Two basic proteins, P1 of molecular weight 14,2000 and P2 of molecular weight 12,300, purified from bovine peripheral nerve, were assayed for biological activity. The P1 protein is an exclusively neuritogenic agent, capable of producing clinical signs of experimental allergic neuritis (EAN) and histological abnormalities in the peripheral nervous system (PNS) of guinea pigs and rabbits, without any changes in their central nervous system (CNS). P2 protein, like the CNS basic encephalitogenic protein (BE), has combined neuritogenic and encephalitogenic activities, therefore it induces in these animals neurological signs and pathological evidence of EAN, as well as histological characteristics of experimental allergic encephalomyelitis (EAE).

Appearance of functional EGF receptor kinase during rodent embryogenesis.

Mouse and rat embryonic tissues at various stages of development were examined for epidermal growth factor (EGF) receptor kinase activity. The phosphorylated EGF receptor from embryonic tissues appeared as a band of mol. wt. 170 000 daltons on SDS gels. It was clearly demonstrable in the developing mouse fetus from 10 days of gestation onwards. The distribution of the EGF receptor kinase was studied in various tissues of 13 day mouse fetuses. The activity was apparent in the skin, developing skeletal muscles and various internal organs but was notably absent in the liver and brain. The amnion was found to be one of the richest sources of activity while the yolk sac was negative, and the placenta was weakly positive. In 16 day rat fetuses the distribution was quite similar to that of the 13 day mouse fetus. The liver acquired EGF receptor kinase activity by 18 days of gestation and had high activity in neonates. Phosphoamino acid analysis revealed that phosphotyrosine was the major labelled amino acid residue in the embryonic tissues. Thus, the EGF receptor of fetal tissues as studied by immune precipitation and phosphorylation appears to be a similar entity to that found in adult mammalian tissues. This functional EGF receptor kinase activity could first be detected at the time of onset of organogenesis.

Changes in the GABA system in experimental allergic encephalomyelitis-induced paralysis.

Abstract— The content of γ‐aminobutyric acid (GABA), but not glutamate, and the uptake of [3H]GABA by synaptosomes was reduced in the lumbar cord of guinea pigs during experimental allergic encephalomyelitis (EAE)‐induced hind limb paralysis. The decrease in glutamate decarboxylase (GAD) activity in the dorsal and ventral parts of the cord was confined to the lumbar region, and appeared before the onset of motor dysfunction. No change in activity was found in the thoracic cord, motor cortex, cerebellum or striatum. GAD activity remained unchanged in animals which were EAE‐sensitized but did not develop the clinical symptoms. Choline acetyltransferase activity did not change in the cord during paralysis.

LYMPHOCYTES SENSITISED TO BASIC ENCEPHALITOGEN IN PATIENTS WITH MULTIPLE SCLEROSIS UNRESPONSIVE TO STEROID THERAPY

Abstract Patients in various stages of multiple sclerosis (M.S.) were tested for peripheral-blood lymphocytes sensitised to purified basic brain encephalitogen (B.E.) by measuring specific transformation in vitro. These patients included thirteen who were having steroid therapy when tested. Lymphocyte transformation in response to B.E. was significant in five patients who, without exception, had not responded clinically to steroid therapy. The other eight patients, whose lymphocytes were not transformed by B.E., all improved markedly on steroid therapy. Fifteen patients tested when they were not receiving steroids all had negative lymphocyte-transformation tests. Included in this group were three of the five patients who responded positively after initiation of steroid treatment. Patients with other unrelated neurological disorders had negative tests whether or not they had been receiving steroid treatment at the time. Normal subjects were also negative. These findings demonstrate that some patients with M.S. show a cell-mediated immune response to the antigen which induces experimental allergic encephalomyelitis. They may also lead to new ideas on the efficacy and desirability of indiscriminate steroid therapy for patients with M.S.