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Epithelial cells are effective targets for lymphocyte stimulation in vitro. The magnitude of response to incompatible epithelial cells was equal to or slightly greater than that following incubation with lymphoid cells. Lymph node lymphocytes appear slightly more reactive to epithelia than comparable preparations of spleen cells. This model was used to study whether differentiation antigens of skin (Sk) which are not expressed on lymphoid cells can provoke an in vitro allograft reaction. [ABSTRACT FROM AUTHOR]

Migration patterns of 51Cr-labelled murine lymph node cells were studied in syngeneic, allogeneic, semi-allogeneic and congenic strain combinations. In certain allogeneic and semi-allogeneic combinations with strong H-2 histoincompatibility, reduced migration of a donor population representing recirculating lymphocytes into recipient lymph nodes was observed. This phenomena could be reproduced in congenic strains differing only at the H-2 locus, and was not seen in congenic strains differing at the Ly-A, Ly-B, RZ, M, or θ loci. The kinetics of reduced lymphocyte homing to allogeneic lymph nodes and the role of host and donor recognition were investigated. These studies are discussed in relation to possible mechanisms of action, and relevance to factors regulating lymphocyte recirculation. [ABSTRACT FROM AUTHOR]

Antilymphocyte globulin (ALG) and to a lesser extent normal rabbit globulin (NRG), when given to mice prior to immunization with sheepRBC suppress both the γM and γG2a responses. Globulin injected after the antigen suppresses the γG2a response, augments the γG1 response and has little effect on the γM response. These effects are also observed in mice partially paralysed to rabbit γ globulin In another system—the response to hapten-protein conjugates precursors of antibody producing cells were found to be more resistant to ALS treatment in vivo than were helper celIs. It is concluded that the suppressive effects of ALG treatment are largely due to the direct action of ALG on helper cells (Tcells). The mechanism of the adjuvant-like effect is nuclear. [ABSTRACT FROM AUTHOR]