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S Livnat

Publications and source records attributed to S Livnat.

6 recordsLinked to original sources
PubMed1976

Recruitment of effector lymphocytes by initiator lymphocytes. In vivo migration of in vitro sensitized initiator T lymphocytes.

We previously found that mouse T lymphocytes sensitized in vitro against allo- or syngeneic fibroblasts, upon injection into syngeneic recipients, do not themselves differentiate into effector cells, but recruit effector T lymphocytes within the draining lymph nodes. As a result of sensitization, these initiator lymphocytes acquire a trypsin-sensitive membrane property which is necessary for recruitment. We now report studies on the in vivo migratory behavior of initiator lymphocytes following sensitization. We injected 51Cr-labeled initiator lymphocytes into recipient footpads and found significantly increased migration of sensitized cells to the draining popliteal lymph node (PLN) during the first day. By amputation of the foot at various times, we showed that migration during the first 12-24 hours was critical for subsequent recruitment. Trypsin treatment of initiator lymphocytes abolished this accelerated migration. Lymphocytes triggered nonspecifically by Con A migrated to the PLN like antigen-sensitized cells. We also compared the migration of injected lymphocytes from the footpad to the PLN in graft-versus-host and host-versus-graft reactions, and found these reactions to differ both from each other and from recruitment in terms of lymphocyte migration. These findings are discussed in terms of the physiology of the cell-mediated immune response and the notion of peripheral sensitization.

Animals↗
PubMed1976

Recruitment of effector lymphocytes by initiator lymphocytes. Recruited lymphocytes are immunospecific and include graft-versus-host-reactive lymphocytes.

We have shown previously that initiator T lymphocytes (ITL), sensitized in vitro against fibroblast antigens, recruit effector T cells in vivo. After injection into hind footpads of syngeneic recipients, sensitized ITL migrated to the draining popliteal lymph nodes (PLN) and activated a trapping mechanism by which circulating lymphocytes were recruited in the PLN. This paper reports experiments designed to test the immunospecificity of these recruited T lymphocytes (RTL). We found that immunospecific RTL were depleted from other lymphoid organs during recruitment in the PLN. However, immunospecific ITL were not depleted from spleens during PLN recruitment. Thus ITL and RTL are functionally distinguishable. We show that specific GVH reactive lymphocytes were also lost from spleens and distal lymph nodes during trapping of RTL in the PLN. Thus, the trapping phase of the recruitment response is immunospecific, as are the sensitization and effector phases. The trapped RTL are antigen-specific, and include the pool of GVH-reactive-lymphocytes committed to the same alloantigen. Thus, it appears that GVH-reactive cells respond to syngeneic ITL sensitized against allogeneic fibroblasts.

Animals↗