Severe combined immunodeficiency mice engrafted with human T cells, B cells, and myeloid cells after transplantation with human fetal bone marrow or liver cells and implanted with human fetal thymus: a model for studying human gene therapy.

To develop an in vivo model wherein human hematopoiesis occurs, we transplanted severe combined immunodeficiency (SCID) mice with either human fetal bone marrow (HFBM) or human fetal liver (HFL). After transplantation of SCID mice with cultured HFBM (BM-SCID-hu mice) or HFL cells (Liv-SCID-hu mice), significant engraftment of the mouse bone marrow (BM) and population of the peripheral blood with human leukocytes was detected. Human colony-forming unit-granulocyte macrophage and burst forming unit-erythroid were detected in the BM of the BM-SCID-hu and Liv-SCID-hu mice up to 8 months after transplantation. When the HFBM or HFL cells were transduced with a retroviral vector before transplantation, integrated retroviral sequences were detected in human precursor cells present in the SCID mouse BM and in leukocytes circulating in the peripheral blood (PB) up to 7 months after transplantation. The PB of the BM-SCID-hu mice also became populated with human T cells after implantation with human thymic tissue, which provided a human microenvironment wherein human pre-T cells from the BM could mature. When the HFBM was retrovirally transduced before transplantation, integrated retrovirus was detected in sorted CD4+CD8+ double positive and CD4+ single positive cells from the thymic implant and CD4+ cells from the PB. Taken together, these data indicated that the BM of our BM-SCID-hu and Liv-SCID-hu mice became engrafted with retrovirally transduced human hematopoietic precursors that undergo the normal human hematopoietic program and populate the mouse PB with human cells containing integrated retroviral sequences. In addition to being a model for studying in vivo human hematopoiesis, these mice should also prove to be a useful model for investigating in vivo gene therapy using human stem/precursor cells.

Inhibition of acute in vivo human immunodeficiency virus infection by human interleukin 10 treatment of SCID mice implanted with human fetal thymus and liver.

To improve the usefulness of in vivo mode for the investigation of the pathophysiology of human immunodeficiency virus (HIV) infection, we modified the construction of SCID mice implanted with human fetal thymus and liver (thy/liv-SCID-hu mice) so that the peripheral blood of the mice contained significant numbers of human monocytes and T cells. After inoculation with HIV-1(59), a primary patient isolate capable of infecting monocytes and T cells, the modified thy/liv-SCID-hu mice developed disseminated HIV infection that was associated with plasma viremia. The development of plasma viremia and HIV infection in thy/liv-SCID-hu mice inoculated with HIV-1(59) was inhibited by acute treatment with human interleukin (IL) 10 but not with human IL-12. The human peripheral blood mononuclear cells in these modified thy/liv-SCID-hu mice were responsive to in vivo treatment with exogenous cytokines. Human interferon gamma expression in the circulating human peripheral blood mononuclear cells was induced by treatment with IL-12 and inhibited by treatment with IL-10. Thus, these modified thy/liv-SCID-hu mice should prove to be a valuable in vivo model for examining the role of immunomodulatory therapy in modifying HIV infection. Furthermore, our demonstration of the vivo inhibitory effect of IL-10 on acute HIV infection suggests that further studies may be warranted to evaluate whether there is a role for IL-10 therapy in preventing HIV infection in individuals soon after exposure to HIV such as for children born to HIV-infected mothers.

Divergent effects of chronic HIV-1 infection on human thymocyte maturation in SCID-hu mice.

We have recently developed a modified SCID-hu mouse model in which the implanted human thymus and liver (hu-thy/liv) and human peripheral T cells become infected with HIV-1 after i.p. inoculation. By using this model, we evaluated the effect of HIV-1 infection on thymic maturation and observed that different HIV-1 strains had divergent effects of thymic maturation. Although minimal effects on continued thymopoiesis in the hu-thy/liv implant were observed after chronic infection with two primary patient isolates, HIV-1(28) and HIV-1(59), and with HIV-1ADA, HIV-1Ba-L, HIV-1JR-CSF, HIV-1JR-FL, and HIV-1SF162, significant thymocyte depletion was detected after infection with HIV-1IIIB and HIV-1RF. Thus, the effect of HIV-1 infection on thymocyte maturation may depend upon the strain of HIV-1 infecting the thymus. Despite the minimal effects on thymopoiesis observed in the hu-thy/liv implanted in SCID-hu mice 6 mo after infection with HIV-1(28), significant changes were seen in the human T cell population circulating in the peripheral blood of these mice. These changes ranged from an inversion of the CD4/CD8 ratio of peripheral human T cells in some SCID-hu mice to the almost complete depletion of peripheral human T cells observed in other SCID-hu mice. Because these effects were associated with the detection of HIV-1 infection of the peripheral human T cells, these modified SCID-hu mice should prove to be a valuable model for investigating the effects of chronic HIV-1 infection on the peripheral human T cell population.

Reconstitution of SCID mice with human lymphoid and myeloid cells after transplantation with human fetal bone marrow without the requirement for exogenous human cytokines.

Investigation of human hematopoietic maturation has been hampered by the lack of in vivo models. Although engraftment of irradiated C.B-17 scid/scid (SCID) mice with human progenitor cells occurred after infusion with human pediatric bone marrow cells, significant engraftment of the mouse bone marrow with human cells was dependent upon continuous treatment with exogenous human cytokines. Furthermore, despite cytokine treatment, only minimal peripheral engraftment of these mice with human cells was observed. In the present study, after infusion of irradiated SCID mice with pre-cultured human fetal bone marrow cells (BM-SCID-hu mice), their bone marrow became significantly engrafted with human precursor cells and their peripheral lymphoid compartment became populated with human B cells and monocytes independently of the administration of extraneous human cytokines. Examination of the bone marrow of the BM-SCID-hu mice for human cytokine mRNA gene expression demonstrated human leukemia inhibitory factor mRNA and interleukin 7 mRNA in nine of nine BM-SCID-hu mice and macrophage-colony-stimulating factor mRNA in seven of eight BM-SCID-hu mice. This was an intriguing observation because these cytokines regulate different stages of human hematopoiesis. Since engraftment occurs in the absence of exogenous cytokine treatment, the BM-SCID-hu mouse model described should provide a useful in vivo system for studying factors important in the maturation of human myeloid and lymphoid cells in the bone marrow and the behavior of the mature human cells after dissemination into the peripheral lymphoid tissue.

Disseminated human immunodeficiency virus 1 (HIV-1) infection in SCID-hu mice after peripheral inoculation with HIV-1.

A small animal model that could be infected with human immunodeficiency virus 1 (HIV-1) after peripheral inoculation would greatly facilitate the study of the pathophysiology of acute HIV-1 infection. The utility of SCID mice implanted with human fetal thymus and liver (SCID-hu mice) for studying peripheral HIV-1 infection in vivo has been hampered by the requirement for direct intraimplant injection of HIV-1 and the continued restriction of the resultant HIV-1 infection to the human thymus and liver (hu-thy/liv) implant. This may have been due to the very low numbers of human T cells present in the SCID-hu mouse peripheral lymphoid compartment. Since the degree of the peripheral reconstitution of SCID-hu mice with human T cells may be a function of the hu-thy/liv implant size, we increased the quantity of hu-thy/liv tissue implanted under the renal capsule and implanted hu-thy/liv tissue under the capsules of both kidneys. This resulted in SCID-hu mice in which significant numbers of human T cells were detected in the peripheral blood, spleens, and lymph nodes. After intraimplant injection of HIV-1 into these modified SCID-hu mice, significant HIV-1 infection was detected by quantitative coculture not only in the hu-thy/liv implant, but also in the spleen and peripheral blood. This indicated that HIV-1 infection can spread from the thymus to the peripheral lymphoid compartment. More importantly, a similar degree of infection of the hu-thy/liv implant and peripheral lymphoid compartment occurred after peripheral intraperitoneal inoculation with HIV-1. Active viral replication was indicated by the detection of HIV-1 gag DNA, HIV-1 gag RNA, and spliced tat/rev RNA in the hu-thy/liv implants, peripheral blood mononuclear cells (PBMC), spleens, and lymph nodes of these HIV-1-infected SCID-hu mice. As a first step in using our modified SCID-hu mouse model to investigate the pathophysiological consequences of HIV-1 infection, the effect of HIV-1 infection on the expression of human cytokines shown to enhance HIV-1 replication was examined. Significantly more of the HIV-1-infected SCID-hu mice expressed mRNA for human tumor necrosis factors alpha and beta, and interleukin 2 in their spleens, lymph nodes, and PBMC than did uninfected SCID-hu mice. This suggested that HIV-1 infection in vivo can stimulate the expression of cytokine mRNA by human T cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Saline-instillation abortion with laminaria and megadose oxytocin.

This study examines the effect of laminaria and oxytocin in 638 saline instillation abortions. Laminaria were inserted into the cervical canal in the physician's office 2 to 3 hours before admission to hospital for instillation. Pitocin was given intravenously at a rate of 417 to 555 mu/min starting 2 hours after instillation. Pitocin was given intravenously at a rate of 417 to 555 mu/min starting 2 hours after instillation. Center for Disease Control (CDC) criteria were used to define complications in the present series. Complication rates compared favorably to those in a national CDC study of traditional saline procedures. Instillation-abortion times averaged 12.5 hours in the present series, about half the time previously reported for saline abortion. If confirmed by other studies, laminaria and oxytocin will be beneficial adjuncts for managing patients aborted by saline instillation.

PIP: The procedure for managing 2nd trimester patients undergoing abortion in a physician's office by saline solution instillation with laminaria and megadose oxytocin has considerable advantages, with complication rates comparably favorable to those in a national study, and an instillation-abortion (I-A) time of 12.5 hours, about 1/2 of the time previously reported for saline abortion. The 638 patients, estimated by palpation to be of more than 14 but not more than 24 weeks gestation are a consecutive series of women aborted by instillation after laminaria dilation. After the abortion, procedure for which is described, data and follow-up reports were analyzed. The I-A time ranged from 3 to 46 hours, with a mean of 12.5 hours. Although no overall association was seen, the I-A times less than 16 hours were somewhat less common when 4 or more laminaria sticks were used. The complications are compared to those of the large saline series reported by the Center for Disease Control, and it is concluded that the use of laminaria and megadose oxytocin to reduce I-A times does not incur any greater risk of complications from the procedure. If confirmed by other studies, laminaria and oxytocin will be useful adjuncts for managing patients aborted by saline instillation.