Effects of plasmapheresis on the course of experimental allergic neuritis in rabbits

Experimental allergic neuritis was induced in 30 rabbits with extract of bovine peripheral nerve in complete Freund's adjuvant. Of the 22 animals that completed the study, nine animals were plasmapheresed within two weeks of inoculation and 13 animals served as controls. The plasmapheresed animals developed a less severe form of EAN than the controls. Differences were apparent in clinical weakness, weight loss, degree of dispersion of the muscle action potential and histological changes.     

A characterization of human tonsillar lymphocytes after separation from other tonsillar cells in an isokinetic gradient of ficoll in tissue culture medium.

Purified human tonsillar lymphocytes responded less to mitogentic stimulation than did unseparated tonsillar cells. Their response to mitogens was restored when they were combined with cells from all other gradient fractions. We interpret our data as evidence that the majority of tonsillar lymphocytes require the presence of more rapidly sedimenting cells for a maximum response to the tested mitogens. The purified tonsillar lymphoyctes were 47.0% lymphocytes that have detectable surface immunoglobulin and 29.9% lumphocytes that form rosettes with sheep red blood cells. The predominant cell surface immunoglobulin was IgM. Digestion of the tonsil with trypsin yielded tenfold more plasma cells, more vialbe cells, and a larger proportion of blasts, histiocytes, and binucleated cells than were obtained by mechanical dissociation of the tissue.     

A new method of measuring the deformability of the red cell membrane

Red cells moving in a stream of fluid can be arrested by means of a network of fibrin threads. Those cells which fold over a fibrin thread present to view a flat strap-like portion of membrane in which the strain can be easily observed and accurately measured both optically and by scanning electron microscopy. Preliminary results obtained by this method show elastic strains of nearly 300% and indicate that the stress required to produce these large strains is an order of magnitude greater than that reported by other methods.     

ADJUVANT-ANTIGEN RELATIONSHIPS IN THE PRODUCTION OF EXPERIMENTAL "ALLERGIC" ENCEPHALOMYELITIS IN THE GUINEA PIG

Quantitative relationships between the amounts of encephalitogenic neural tissue and mycobacterial adjuvant are presented for the guinea pig, for comparison with similar results obtained in the mouse and presented in an accompanying paper by Lee and Schneider (27). Definite threshold amounts of both neural encephalitogenic and mycobacterial adjuvant can be defined. With the proper amounts of each component, 100 per cent of guinea pigs can be made to develop EAE, 97 per cent dying of it, and over 50 per cent becoming paralyzed by the 12th day after challenge. With moderate amounts of encephalitogen the severity and incidence of EAE can be very great, but this encephalitogenic potential can be masked if large amounts of mycobacteria are employed. The mechanism of this masking effect by excess adjuvant is not known, but speculation centers upon the possibility of competition of antigens of the mycobacteria at the expense of those of the encephalitogen.     

Red cell membrane deformability: new data

Red cells arrested by fine fibers and subjected to drag forces in a moving stream of fluid can be stressed beyond the point of rupture. The technique, which is basically an in vitro analogue of the microangiopathic hemolytic state, thus permits a study of red cell behavior over the entire range of stress that the membrane can withstand. Measurements made by this approach show an exponential relationship between the velocity of fluid flow and the resultant membrane deformation. Such exponential membrane deformation is consistent with the morphology of red cell fragments and appears to explain their mechanism of formation.