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D L Peavy

Publications and source records attributed to D L Peavy.

28 records · Page 2Linked to original sources
PubMed1975

Cell-mediated immune responses in vitro. II. Simultaneous generation of cytotoxic lymphocyte responses to two sets of alloantigens of limited cross-reactivity.

The conditions for generation of simultaneous and independent cytotoxic lymphocyte (CL) responses to each of two sets of alloantigens of limited cross-reactivity by mouse spleen cells in vitro have been investigated. Responder spleen cells were incubated with mitomycin C-treated C57BL/6 (H-2b) or DBA/2 (H-2d) stimulator spleen cells and day 5 CL responses were assayed with 51Cr-labeled EL-4 leukemia (H-2b) and P815 mastocytoma (H-2d) as target cells. Spleen cells from mice of the various H-2 haplotypes tested differed greatly in their ability to develop specific CL responses against alloantigens on the stimulator spleen cells and in the degree of cross-reactive cytotoxic activity against target cells bearing alloantigens not present on the stimulator spleen cells. In contrast to the other strains examined, DBA/1 (H-2q) spleen cells developed specific CL responses to either H-2b or H-2d alloantigens without exhibiting significant cross-reactive activity on the inappropriate target cell. The CL responses to H-2b and H-2d alloantigens by DBA/1 spleen cells were comparable in magnitude and had similar stimulator cell-dose requirements. Further, DBA/1 spleen cells developed CL responses of normal magnitude simultaneously against both target cells when incubated with both mitomycin C-treated C57BL/6 and DBA/2 stimulator cells.

Animals↗
PubMed1975

Cell-mediated immune responses in vitro. III. Elimination of specific cytotoxic lymphocyte responses by 3H-thymidine suicide.

The role of cellular proliferation in the development of cytotoxic lymphocyte (CL) responses in one-way mixed lymphocyte reactions was investigated by using tritiated thymidine of high specific activity to kill proliferating cells. To develop maximum CL responses, responding lymphoid cells must proliferate for approximately 72 hr; thereafter, precursors of CL appear to differentiate into active CL without further proliferation. Different alloantigen-sensitive precursor cell populations participate in the CL responses to each of two sets of stimulating alloantigens. When cells responding to one set of alloantigens were selectively destroyed after incorporating the hot thymidine, the surviving cells retained the capacity to develop a normal CL response to the second set of alloantigens.

Animals↗
PubMed1974

Cell-mediated immune responses in vitro. I. Suppression of the generation of cytotoxic lymphocytes by concanavalin A and concanavalin A-activated spleen cells.

The effects of soluble concanavalin A (Con A) or Con A-activated spleen cells on the generation of cytotoxic lymphocytes (CL) in mixed leukocyte cultures (MLC) were examined. Mitogenic concentrations of soluble Con A or small numbers of Con A-activated spleen cells substantially inhibited CL responses. The suppression was partial rather than absolute and was critically dependent upon the concentration and time of addition of soluble Con A or Con A-activated spleen cells to the MLC. Suppressive effects of Con-A activated spleen cells were mediated by T cells since suppressor cell activity was abrogated by treatment of spleen cells with anti-theta serum and complement before or after Con A activation. X irradiation of spleen cells before Con A treatment also abrogated generation of suppressor cell activity. After activation by Con A, however, the function of suppressor cells was radioresistant. Although the precise mechanism(s) of suppression is, as yet, unknown, the precursors of CL must be exposed to Con A-activated cells during the early phases of the immune response for suppression to occur. Kinetic studies revealed that suppression of CL responses was not due to a failure to initiate an immune response, but represented a response which developed initially, but subsequently aborted. The relevance of these observations to the concepts of T-cell-T-cell interaction and regulatory control of immune responses by T cells is discussed.

Animals↗
PubMed1974

In vitro and in vivo effects of endotoxin on mouse peritoneal cells.

The in vitro effect of endotoxin (LPS) on unfractionated mouse peritoneal cells and cells fractionated into glass adherent and nonadherent populations was studied. LPS caused blast transformation and deoxyribonucleic acid synthesis in the nonadherent, nonphagocytic cells. There was no evidence of a mitogenic effect on macrophages. Instead, a cytotoxic effect was noted. When incubated with unfractionated peritoneal cells, LPS was still cytotoxic for macrophages, but the mitogenic effect for nonadherent cells was decreased or ablated. The intraperitoneal administration of LPS to mice resulted in an acute inflammatory response with a transient depletion of mononuclear cells. There was no stimulation of division of macrophages. Data were obtained which indicated that local cell division is an important factor in the normal turnover of peritoneal macrophages.

Animals↗
PubMed1973

Differential morphology of mouse spleen cells stimulated in vitro by endotoxin, phytohemagglutinin, pokeweed mitogen and staphylococcal enterotoxin B.

The in vitro mitogenic effects of endotoxin (LPS), phytohemagglutinin (PHA), pokeweed mitogen (PWM) and staphylococcal enterotoxin B (SEB) on mouse spleen cells were studied by light and electron microscopy. By light microscopy, LPS was found to "transform" a culture largely composed of small lymphocytes into "large lymphocytes" which did not synthesize DNA and into blast cells which did synthesize DNA. The blast cells were morphologically similar to those transformed by PHA, PWM and SEB. By electron microscopy, a large percentage of the endotoxin-transformed cells developed extensive dilated rough ER. Their appearance was similar to that reported by others for cells stimulated by PWM, but in our hands the development of rough ER was more conspicuous in LPS-stimulated cells. In contrast, PHA and SEB produced few blast cells which contained significant rough ER. The morphologic observations are consistent with the hypothesis that the mitogenic effect of endotoxin is on bone-marrow-derived lymphocytes. This effect may relate to the known adjuvant effect of endotoxin in vivo.

Animals↗
PubMed1971

Interferon production in mixed lymphocyte cell cultures.

Mixed lymphocyte cultures from mice with marked differences in major and minor histocompatibility antigens were found to produce an inhibitor of viral replication with properties of interferon. Cultures produced maximal amounts of interferon at approximately 72 to 96 hr, a time when maximal stimulation of deoxyribonucleic acid synthesis also occurred.

Journal Article↗