Specialized NK cells are recruited in high numbers to the mammalian embryo implantation sites, yet remain pregnancy compatible. It is not well understood whether uterine NK (uNK) cells become adversely activated and mediate fetal demise, a common complication of early pregnancy. In this study we show that mating of IL-10−/− mice resulted in fetal resorption or intrauterine growth restriction in response to very low doses of LPS. Pregnancy in congenic wild-type mice was normal even at 10-fold higher LPS doses. Fetal resorption in IL-10−/− mice was associated with a significant increase in uNK cell cytotoxic activation and invasion into the placenta. Depletion of uNK cells, TNF-α neutralization, or IL-10 administration rescued pregnancy in LPS-treated IL-10−/− animals. Our results identify an immune mechanism of fetal demise involving IL-10 deficiency, NK cells, and inflammation. These results may provide insight into adverse pregnancy outcomes in humans.

Mirasol PRT treatment is able to functionally inactivate WBCs in blood products along with inactivating pathogens and should prevent immunological consequences resulting from the presence of WBCs in blood products.

When B cells are deprived of signaling through CD40, they exhibit the ability to induce T cell tolerance. The in vivo administration of anti-gp39 and allogeneic B cells diminished the ability of mice to mount an allogeneic response. Tolerance induction was specific for the haplotype expressed on the allogeneic B cells. Selective allospecific unresponsiveness was induced in the CD8 and CD4 compartments by the administration of anti-gp39 and class II-deficient B cells or class I-deficient B cells, respectively. As predicted by studies with anti-gp39 treatment, diminished allospecific responsiveness was induced by the administration of B cells to mice genetically deficient in gp39. Taken together, these data are consistent with the premise that deprivation of CD40 signaling engenders B cells with enhanced tolerogenicity. These studies provide insights into the tolerogenic capacity of resting B cells and outlines a practical approach to exploit this function.

Allogeneic bone marrow transplantation relies on immunosuppression, which controls graft-versus-host disease (GVHD) and allows engraftment at the expense of diminished graft versus-tumor (GVT) activity. Advances in hematologic transplantation have prompted the development of effective, less-toxic regimens that attempt to balance GVH and GVT immunoreactions. We analyzed the safety and efficacy of haploidentical transplantation in a Phase I/II nonimmunosuppressive, nonmyeloablative setting. A total of 41 patients with relapsed refractory cancer received 100 cGy of total body irradiation (TBI), along with an infusion of 1 x 10(6) to 2 x 10(8) CD3+ cells/kg; 29 patients received the highest dose. A postinfusional cellular graft rejection syndrome resembling engraftment syndrome was noted at the 2 highest CD3+ infusion cohorts. There were 26 patients with hematologic malignancies with 14 responses, 9 of which were major. Two of 6 patients with lymphoma remained free of disease at 76 months and 82 months, respectively; there were 5 durable complete responses and 4 partial responses in 13 patients with acute myelogenous leukemia (AML). All responses occurred outside of donor chimerism. TBI at 100 cGy followed by HLA-haploidentical immunotherapy is a biologically active therapy for patients with refractory AML and lymphoma. Possible mechanisms contributing to its effectiveness include initial GVT kill, breaking of host tolerance to tumor through cross-reactive alloreactive responses, persistent nondetectable microchimerism, or some combination of these.

The ability to effectively inactivate WBCs in fresh whole blood using Rb-UV, prior to separation into components, provides the transfusion medicine community with a potential alternative to gamma irradiation.

Chronic and acute graft-versus-host disease (cGVHD and aGVHD) result from donor cells responding to host disparate MHC alleles. In cGVHD (H-2d --H-2bd)), heightened polyclonal immunoglobulin production is due to the interaction of donor allospecffic helper T cells (Th) and the host B cells. In vivo administration of antibody to the ligand for CD40, gp39, blocked cGVHD-induced serum anti-DNA autoantibodies, IgE production, spontaneous immunoglobulin production in vitro, and associated splenomegaly. Antibody production remained inhibited for extended periods of time after termination of anti-gp39 administration. Antiallogeneic CTL responses induced in aGVHD were also prevented by the in vivo administration of anti-gp39 as was the associated splenomegaly. These data suggest that CD40-gp39 interactions are critical in GVHD and that CD40-gp39 may be a valuable ligand-receptor pair for targeting immunotherapeutic agents to control GVHD. (J. Clin. Invest. 1994.

We have previously shown that the inhibition of histone deacetylases (HDACs) protects the heart against acute myocardial ischemia and reperfusion injury. We also demonstrated that HDAC inhibition stimulates myogenesis and angiogenesis in a cultured embryonic stem cell model. We investigate whether in vivo inhibition of HDAC preserves cardiac performance and prevents cardiac remodeling in mouse myocardial infarction (MI) through the stimulation of endogenous regeneration. MI was created by ligation of the left descending artery. Animals were divided into three groups: 1) sham group, animals that underwent thoracotomy without MI; 2) MI, animals that underwent MI; and 3) MI ϩ trichostatin A (TSA), MI animals that received a daily intraperitoneal injection of TSA. In addition, infarcted mice received a daily intraperitoneal injection of TSA (0.1 mg/kg), a selective HDAC inhibitor. 5-Bromo-2-deoxyuridine (50 mg/kg) was delivered every other day to pulse-chase label in vivo endogenous cardiac replication. Eight weeks later, the MI hearts showed a reduction in ventricular contractility. HDAC inhibition increased the improvement of myocardial functional recovery after MI, which was associated with the prevention of myocardial remodeling and reduction of myocardial and serum tumor necrosis factor ␣. HDAC inhibition enhanced the formation of new myocytes and microvessels, which was consistent with the robust increase in proliferation and cytokinesis in the MI hearts. An increase in angiogenic response was demonstrated in MI hearts receiving TSA treatment. It is noteworthy that TSA treatment significantly inhibited HDAC activity and increased phosphorylation of Akt-1, but decreased active caspase 3. Taken together, our results indicate that HDAC inhibition preserves cardiac performance and mitigates myocardial remodeling through stimulating cardiac endogenous regeneration.

Skeletal muscle transplantation strategies for muscle repair or gene therapy involve either the injection of proliferating myoblasts followed by fusion with host myofibers or implantation of ex vivo differentiated myofibers; however, both implant procedures are associated with significant cell loss. Biodegradable porous, gas-foamed poly-lactide-co-glycolide (PLG) scaffolds have desirable characteristics for cell transfer and were used to study attachment, growth, differentiation and survival of human myogenic cells. Primary human myoblasts suspended in clinical grade extracellular matrixes (ECMs) and adhered to PLG scaffolds differentiated in vitro into high-density tropomyosin positive myofibers. An immunodeficient non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mouse implant model was used to study the transfer and in vivo survival of differentiated human myofibers on these scaffolds. Scaffold rigidity allowed the myofibers to be maintained under tension in vitro and following subcutaneous transplantation in vivo. Following implantation, myofiber density on the PLG scaffolds decreased linearly by 78% over a 4-week period. ECM composed of either Tisseel s fibrin or Zyderm s collagen type I did not significantly affect in vivo cell viability over the 4-week period. Varying PLG scaffold microsphere content (10-100%) also had little effect on cell survival in vivo. In contrast, when the residual NK cell population in the immunodeficient NOD/SCID mouse model was depleted with anti-asialo GM1 (ASGM1) antiserum, in vivo cell survival significantly increased from 22% to 34% after 4 weeks. With further improvements in cell survival, PLG scaffolds may prove useful for the implantation of primary human myofibers in future clinical applications. r