The inflammatory infiltrate of the central nervous system in acute experimental allergic encephalomyelitis (EAE) in the guinea-pig has been isolated and characterized. Inflammatory cells found over the surface of the brain and spinal cord and within the leptomeninges have been isolated by washing, and were subsequently identified by a number of methods. By light microscopy approximately 60% were lymphocytes, 30% were cells of the mononuclear phagocyte series, and 5% were neutrophils: the occasional plasma cell and eosinophil were also identified. E, EA and EAC rosetting tests were used to determine the proportions of T lymphocytes (both early and late), and cells with Fc and C3 receptors respectively. Particular attention was paid to cells of the mononuclear phagocyte series bearing Fc and C3 receptors to determine whether any change or loss of these receptors was apparent. The percentage of phagocytic cells from the brain and spinal cord washes was also determined. Transmission and scanning electron microscopy showed that a large proportion of the inflammatory infiltrate consisted of cells of the mononuclear phagocyte series. This study therefore confirms that the cells of the mononuclear phagocyte series play a predominant role in EAE.

Brain↗

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Quantitation and in vitro analysis of the inflammatory cells in experimental allergic encephalomyelitis in the guinea-pig.

Inflammatory cells from the meninges of guinea-pigs with acute EAE have been isolated and quantitated. A mean of 7.5 x 10(6) cells were recovered from the brains of animals showing clinical signs of disease in contrast to only 1.5 x 10(6) cells in the controls. The immunological specificity of the meningeal inflammatory cells was determined using the lymphocyte transformation test and compared with another inflammatory cell population, the peritoneal exudate cells (PECs), in the same animal. The meningeal exudate cells responded only to the mitogen Concanavalin A (Con A) and not to the antigens myelin basic protein and tuberculin (PPD). In contrast, the PECs proliferated in the presence of both antigens and the mitogen.

Animals↗

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The effect of protecting guinea-pigs against EAE on the meningeal inflammatory cell-infiltrate.

Guinea-pigs were found to be fully protected from the clinical signs of EAE when they were given spinal cord in FIA either 3, 7. or 14 days immunization with spinal cord in FCA. If the animals were protected by the recruitment of suppressor cells then cyclophosphamide (CY) might break this protection. CY at 300 mg/kg and 20 mg/kg was given either before the protective inoculum to try to eliminate suppressor cell precursors or before immunization to eliminate the suppressors cells themselves. No clinical signs of EAE developed in any of these groups of guinea-pigs. It was found, however, that large numbers of meningeal inflammatory cells could be isolated from the brains of guinea-pigs protected from EAE when the protective inoculum was given only 1 week before immunization. These cell numbers were further significantly increased by giving CY in addition to the protective inoculum. The meningeal inflammatory cells and peritoneal exudate cells (PECs) from guinea-pigs protected against EAE were compared to those isolated from animals with acute EAE. These cells from guinea-pigs with acute EAE responded, in the lymphocyte transformation test, to the mitogen. The PECs also responded to the brain antigen, myelin basic protein (MBP) and to tuberculin (PPD). The meningeal inflammatory cells did not respond to either antigen. The PECs from animals protected against EAE responded to mitogen and PPD, but not to MBP, but the meningeal inflammatory cells did not respond to antigen or mitogen. The percentage of T lymphocytes in the meningeal inflammatory infiltrates of protected and unprotected guinea-pigs was similar, but that of phagocytic cells was significantly depressed in the inflammatory infiltrates of animals protected against EAE.

Animals↗

PubMedDate not supplied

Chronic relapsing experimental allergic encephalomyelitis in the guinea-pig: in-vitro analysis of meningeal inflammatory cells.

Inflammatory cells from the meninges of guinea-pigs with chronic relapsing experimental allergic encephalomyelitis (CREAE) have been isolated and compared to a similar cell population obtained from guinea-pigs with acute EAE. A mean of 6.2 x 10(6) cells were recovered from the brains of animals with CREAE while a similar number of cells (8.0 x 10(6)) was obtained from animals with acute EAE. Only 5.3% of the cells from animals with CREAE were found to be phagocytic in contrast with 28% of the cells obtained from animals with acute EAE. The meningeal inflammatory cells from guinea-pigs with CREAE did not respond, in the lymphocyte transformation test, to specific antigens or to mitogen. Peritoneal exudate cells (PECs) from these animals did, however, proliferate in the presence of tuberculin and of mitogen, but not with the brain antigen myelin basic protein (MBP). In contrast, the meningeal inflammatory cells from animals with acute EAE did respond to mitogen and PECs from the same animals responded to both the specific antigens and to the mitogen. The meningeal inflammatory cells and PECs from the guinea-pigs with CREAE did, however, behave in a similar manner to similar cell populations obtained from guinea-pigs fully protected against clinical signs of acute EAE.

Acute Disease↗

PubMedDate not supplied