Edwin M. Lerner

Acute and chronic autoimmune encephalomyelitis: age, strain, and sex dependency. The importance of the source of antigen.

Summary A variety of conditions favoring the production of chronic forms of AE existed between the optimal conditions for acute AE (guinea pig antigen in adult Strain 13/N) and for strong resistance to AE (rabbit antigen in newborn Strain 2/N). The resistance of Strain 2/N guinea pigs to autoimmune encephalomyelitis is not absolute. Older Strain 2/N female guinea pigs regularly develop severe or lethal AE when sensitized with guinea pig spinal cord in Freunds complete adjuvant. Guinea pig spinal cord is a more potent encephalitogen than rabbit spinal cord in Strains 2/N and 13/N guinea pigs. Sensitized Strain 2/N guinea pigs of an age group showing no overt clinical signs of AE nevertheless showed striking histological lesions of AE in the central nervous system.

Involvement of Thymus in Immune Response of Rabbits to Somatic Polysaccharides of Gram-Negative Bacteria

Plaque-forming cells elaborating antibody specific for Salmonella enteritidis somatic antigen have been demonstrated in the thymus of rabbits 5 days after a single systemic injection of a minute amount of this bacterial polysaccharide. A marked decrease in organ weight and loss of thymic cellularity was also seen, and was most pronounced at the time when antibody-forming cells made their appearance.

Adoptive Autoimmune Encephalomyelitis in Inbred Guinea Pigs: Immunological and Histological Aspects

Major variables which determine the induction and severity of adoptive autoimmune encephalomyelitis are the age and strain of the animal, and the amount of killed mycobacteria in the adjuvant. Control of these factors results in consistent production of this disease in high incidence and in severe form. The pathologic changes in the central nervous system can be correlated with the clinical disease. Maturity of the target tissues in the central nervous system of the newborn appears to be an important factor which distinguishes the response of the guinea pig from that of other species.

Autoimmune Encephalomyelitis and Ocular Lesions in Monkeys Sensitized during the Neonatal Period

The neonatal rhesus monkey is susceptible to the induction of autoimmune encephalomyelitis. The disease has been produced regularly by injection of neonatal animals with guinea pig spinal cord antigen in complete Freunds adjuvant. The onset of the disease, as compared with onset in adults, is delayed and is most often heralded by intrinsic eye lesions, notably widespread retinal hemorrhages.

Autoimmune Chorioretinitis in Rhesus Monkeys

Monkeys injected with monkey retinal tissue incorporated in Freunlds complete adjuvant developed ocular lesions characterized by choroiditic patches in the fundus periphery and sheathing of retinal vessels. Bovine retina, monkey choroid plexus, and guinea pig kidney were ineffective in this respect.

Genetic Influence on Experimental Allergic Thyroiditis in Guinea Pigs

After immunization with low doses of guinea pig thyroid extract, incidence of experimental allergic thyroiditis is greater in the Hartley strain of guinea pig than in strain 13.

Histopathology of Lymphocytic Choriomeningitis in Mice Spared by Amethopterin

Summary Mice infected with lymphocytic choriomeningitis virus in doses which were otherwise uniformly fatal were spared by administration of amethopterin. Histological examination of spared animals at intervals ranging from 5 to 57 days revealed greatly modified objective evidence of disease in the majority of these animals. In the acute stage, 82% of the mice showed no disease or extremely modified lesions of LCM. In the chronic stage, 33% showed similarly modified LCM. The remaining mice in both groups showed lesions of active LCM, even as late as 56 days after inoculation. Practically all spared mice gave evidence of multiplication of the virus in the central nervous system.

An Unfortunate Event

After Dement and Kleitman (1) first described a low-voltage, fast electroencephalographic sleep cycle in humans, the same type of activity was described in cats by Dement (2) and later by Jouvet et al. (3). We have duplicated this desynchronized sleep electroencephalogram in five of our cats that have been implanted with bipolar electrodes in various deep and surface structures of the brain. These animals have been trained to go to sleep in a sound-proofed room. Behavioral and electroencephalographic arousal thresholds in response to stimulation of the reticular formation are then recorded. The cats exhibited the normal behavioral and electroencephalographic patterns associated with going to sleep, and after 60 or more minutes of complete isolation they drifted into a very high frequency (40 to 50 per second), low amplitude, desynchronized activity (Fig. iB). As described by Jouvet et al. (3), the animals were completely relaxed and deeply asleep. Especially noticeable are the occasional convulsive limb twitches. One of the cats slept with the eyes partially open during this phase. She showed marked nystagmic movements of the eyeball under relaxed nictitating membranes. Although Dement (4) states that he cannot detect changes in arousal threshold between the fastor slow-wave sleep stages, we have found increases in the reticular formation behavioral arousal thresholds of from 1 to 2.5 volts in all of our cats (Fig. 1). This finding confirms Jouvets report (3) of increased auditory and reticular arousal thresholds during this sleep period. One aspect of this desynchronized sleep stage not yet reported is shown in Fig. 1C. Recticular stimulation that

Suppression of graft-versus-host disease and antibody formation by phytohemagglutinin: Examples of antigen competition

SUMMARY Phytohemagglutinin (PHA) has been used to suppress both graftversus- host disease and antibody formation in mice. However, PHA heated at 100 C for 30 min to destroy its in vitro mitogenicity and certain antigens produced quantitatively similar suppression. Consequently, the immunosuppressive effects of PHA demonstrated in our experiments were unrelated to its in vitro mitogenicity and are probably results of antigen competition

Sensitized Sheep Cell Hemagglutination Reaction in Rats with Experimental Infection of Bone and Joint

Summary 1) Rats infected with a strain of Streptobacillus moniliformis developed an inflammatory reaction in joint regions in 109 of 116 animals. 2) Sensitized sheep cell agglutination titres of the serum euglobulin tested from 55 infected rats were significantly higher than those of 53 uninfected controls.