Successful semiallogeneic and allogeneic bone marrow reconstitution of lethally irradiated adult mice mediated by neonatal spleen cells.

Spleens of fetal/newborn mice less than 3-4 days of age contain a naturally occurring cell population capable of suppressing T-dependent and T-independent immune responses of third-party adult cells both in vitro and in vivo. We have utilized newborn spleen cells to prevent acute graft-versus-host (GVH) disease in lethally irradiated adult hosts reconstituted with semiallogeneic or even allogeneic bone marrow cells. Pretreatment of reconstituting cell populations with newborn spleen cells reduced the incidence of GVH disease from 100% to 20% in semiallogeneic and from 100% to 40% in allogeneic combinations. Long-term-surviving reconstituted hosts proved immunologically unresponsive to both donor and host histocompatibility antigens, yet possessed a fully chimeric lymphoid system responsive to T and B cell mitogens, as well as unrelated third-party alloantigens.

Immunogenicity and tolerogenicity of a major house dust mite allergen, Der p I from Dermatophagoides pteronyssinus, in mice and rats.

Primary immunization of different inbred strains of mice with the house dust mite allergen Der p I (from Dermatophagoides pteronyssinus) adsorbed to adjuvant revealed differences in IgE but not IgG responses. Thus, the CBA and C57 Black strains were shown to be high IgE responders in that persistent IgE was induced which lasted for several months. In contrast, the C3H, AKR and Balb/c strains were judged to be poor responders. Subsequent experiments showed that such responses were adjuvant-independent, refractory to irradiation (850 rad) and that they could be adoptively transferred using immune spleen cells in a dose-dependent manner. At sub-optimal doses, adoptively transferred IgE responses were initiated by either intraperitoneal or intranasal challenge of recipients with allergen in the absence of adjuvant. Allergen-specific IgE in rats was also shown to be strain-dependent, with Brown Norway rats, in contrast to Wistar Furth (WF) and Lou/M rats, being the highest responder strain studied. Repeated intranasal administration of soluble allergen induced IgE tolerance in rats but not mice. However, tolerance was restricted to the low IgE responder phenotype strain, WF.

Hematopoietic effects of continuous intravenous infusion of mice with growth factors produced by the WEHI-3 cell line.

A method for continuous intravenous infusion of unanesthetized adult C3H/HeJ or Wx/Wv anemic mice was designed using cage immobilization and a tail vein catheter connected to a model 940 Harvard infusion pump. Infusates included: WEHI-3 cell line dialyzed, 5 times concentrated conditioned medium containing multi-colony-stimulating factor (C-SF) interleukin 3 (IL-3); purified murine IL-3; bacterial endotoxin; serum-free medium, or normal saline. Mice were monitored at days 5-7 after infusion for complete peripheral blood counts and production of granulocytes in vitro by explanted marrow in long-term bone marrow cultures. We observed a stimulatory effect of WEHI-3 conditioned medium infusion that was not attributable to endotoxin and produced significant increases in peripheral blood WBC count and neutrophils, colony-forming units in spleen and numbers of granulocyte/macrophage colony-forming unit culture responsive to both C-SF-1 (L cell C-SF) and multi-C-SF in vitro. This infusion method should prove valuable for test of the in vivo effects of purified growth factors and molecularly cloned hematopoietins.

Functional effects of splenin32-34 on antibody formation in immunosuppressed mice.

Sublethally irradiated AB/Bln mice (500 cGy) were treated with splenotritin (fragment 32-34 of the splenic hormone splenin) and tested for their capability of producing antibodies against target sheep red blood cells. In x-ray plus splenotritin treated mice antibody forming cells were found earlier and in a higher frequency than in mice treated with x-rays alone.

Prevention of GvHD by a lymphokine.

T lymphocytes which are capable of preventing GvHD when mixed with GvHD inducing cells before grafting and of inhibiting MLR, have been demonstrated in spleen and thymus of neonatal mice and rats. The supernatant of short term cultures of neonatal thymus and spleen contains a factor termed SUF, that produces the same suppressions. SUF has been produced by a number of hybridoma cell lines, that were obtained by fusion of a T lymphoma cell line with neonatal spleen cells. SUF does not reduce CFU-S upon incubation with mouse bone marrow. Suppression by SUF in MLR is not mediated via a cytotoxic mechanism, neither does SUF inhibit proliferation of normal and malignant lymphocytes. Preliminary data suggest that SUF interferes with the action of IL-2 on T effector lymphocytes.

Different responses of two mouse strains to 650 rads and protection by surgical stress.

Radiation survival of C57B1/6J mice after 650 rads improved from 1.7% to 66% when mice were stressed surgically one week before irradiation. Surgical stress one or three weeks before irradiation increased endogenous CFUs and decreased exogenous CFUs in C57B1/6J and DBA/1J mice. Survival may be related to the proportion of stem cells in different phases of the cell cycle, which was abnormal in C57B1/6J mice and compensated for by a greater number of nucleated cells per femur.