449 research outputs found
GENETIC CONTROL OF IMMUNE RESPONSES IN VITRO : V. STIMULATION OF SUPPRESSOR T CELLS IN NONRESPONDER MICE BY THE TERPOLYMERL-GLUTAMIC ACID60-L-ALANINE30-L-TYROSINE10 (GAT)
In recent studies we have found that GAT not only fails to elicit a GAT-specific response in nonresponder mice but also specifically decreases the ability of nonresponder mice to develop a GAT-specific PFC response to a subsequent challenge with GAT bound to the immunogenic carrier, MBSA. Studies presented in this paper demonstrate that B cells from nonresponder, DBA/1 mice rendered unresponsive by GAT in vivo can respond in vitro to GAT-MBSA if exogenous, carrier-primed T cells are added to the cultures. The unresponsiveness was shown to be the result of impaired carrier-specific helper T-cell function in the spleen cells of GAT-primed mice. Spleen cells from GAT-primed mice specifically suppressed the GAT-specific PFC response of spleen cells from normal DBA/1 mice incubated with GAT-MBSA. This suppression was prevented by pretreatment of GAT-primed spleen cells with anti-θ serum plus C or X irradiation. Identification of the suppressor cells as T cells was confirmed by the demonstration that suppressor cells were confined to the fraction of the column-purified lymphocytes which contained θ-positive cells and a few non-Ig-bearing cells. The significance of these data to our understanding of Ir-gene regulation of the immune response is discussed
Monovalent Ion Condensation at the Electrified Liquid/Liquid Interface
X-ray reflectivity studies demonstrate the condensation of a monovalent ion
at the electrified interface between electrolyte solutions of water and
1,2-dichloroethane. Predictions of the ion distributions by standard
Poisson-Boltzmann (Gouy-Chapman) theory are inconsistent with these data at
higher applied interfacial electric potentials. Calculations from a
Poisson-Boltzmann equation that incorporates a non-monotonic ion-specific
potential of mean force are in good agreement with the data.Comment: 4 pages, 4 figure
Vaporization and Layering of Alkanols at the Oil/Water Interface
This study of adsorption of normal alkanols at the oil/water interface with
x-ray reflectivity and tensiometry demonstrates that the liquid to gas
monolayer phase transition at the hexane/water interface is thermodynamically
favorable only for long-chain alkanols. As the alkanol chain length is
decreased, the change in excess interfacial entropy per area decreases to zero.
Systems with small values of excess interfacial entropy form multi-molecular
layers at the interface instead of the monolayer formed by systems with much
larger excess interfacial entropy. Substitution of n-hexane by n-hexadecane
significantly alters the interfacial structure for a given alkanol surfactant,
but this substitution does not change fundamentally the phase transition
behavior of the monolayers. These data show that the critical alkanol carbon
number, at which the change in excess interfacial entropy per area decreases to
zero, is approximately six carbons larger than the number of carbons in the
alkane solvent molecules.Comment: 27 pages, 10 figures, to be published in J. Phys. Cond. Ma
IMMUNOCHEMICAL STUDIES ON THE ANTIGENIC DETERMINANTS REQUIRED TO ELICIT DELAYED AND IMMEDIATE HYPERSENSITIVITY REACTIONS
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