New experimental model of meningeal leukemia.

Meningeal leukemia is a common, often fatal complication of leukemia. Efforts to devise better prophylactic or therapeutic regimens have been limited by large gaps in knowledge regarding the pathogenesis of the process. This report describes a new experimental model of meningeal leukemia that should facilitate its study and fill some of the gaps. T-cell lymphomas, originally induced in C3H mice by Gross murine leukemia virus, were established as transplantable tumor lines in syngeneic mice. Three of ten tumor lines produced meningeal leukemia when injected i.v. into normal recipient animals. The others produced predominantly visceral lymphomas.

Epithelial morphogenesis in developing Artemia: the role of cell replication, cell shape change, and the cytoskeleton.

The roles of cell replication and shape change as morphogenetic forces in epithelial invagination were examined in instar II Artemia. The epidermal cells underwent a fixed pattern of cell division during the first 5 hr of instar II. Greater cell replication in the thoracopod bud (ThB) than in the arthrodial membrane (AM) region resulted in a higher density of epidermal cells in the ThB region (differential cell density). The ratio of cell density (AM/ThB) declined from 1.0 to less than 0.80 by Hour 2 of instar II. Invagination of the AM occurred during Hour 4 when the AM/ThB reached 0.75. A 2-hr pulse with 5'-fluorodeoxyuridine (FudR) during instar I delayed completion of the cell replication pattern and development of transverse cell files in the ThB region for a period equal to the length of the exposure. The delay in the cell division program resulted in a cell density ratio of 0.93 at Hour 4, a value normally observed in Hour 2 larvae, and evagination of the epidermis did not occur at apolysis (Hour 4). The FudR treatment did not perturb the cytoskeleton or the initial steps in cell shape change and the larvae formed small segments during instar III. Cell shape change within the AM began during Hour 4 as this region became significantly thinner than the neighboring ThB region (thickness ratio, AM/ThB = 0.77). Before apolysis the AM cells became wedge shaped, a change which occurred when the basal region of the cell enlarged. The microtubules and microfilaments were reorganized from the apical cytoplasm to the lateral border of apposing AM cells. Following apolysis (Late Hour 4) shape change was completed as the cells attained a thin spindle form, with microtubule- and microfilament-rich filopodial extensions which overlapped adjacent AM cells. As contact with ThB cells shifted from lateral to apicolateral, the AM cells formed the innermost edge of the invagination. Microtubules in the differentiating AM cells contained tyrosinated, detyrosinated, and acetylated alpha-tubulin isoforms. Treatment with nocodazole, colchicine, taxol, or cytochalasin B blocked AM cell shape change and inhibited segmentation, but did not affect the mitotic pattern or differential cell density. We conclude that the specific pattern of cell division led to differential cell density which, along with AM cell shape change, established the conditions necessary to achieve epidermal evagination.

Monoclonal antibody identification of a type II alveolar epithelial cell antigen and expression of the antigen during lung development.

A monoclonal antibody identifying an antigen expressed by rat type II alveolar epithelial cells, but not by type I epithelial cells or other mature lung cells, was produced by immunization of mice with cells of the rat L2 cell line. The antigen recognized by the antibody was present on the microvillous luminal surface of type II epithelial cells. In adult rat lung, only type II epithelial cells bound the antibody. During fetal development the antigen was expressed by cuboidal epithelial cells lining the respiratory ducts of the first divisions of the tracheal bud, but not by epithelial cells lining the esophagus or trachea. The antigen continued to be expressed by cuboidal epithelial cells lining the larger respiratory ducts until approximately 19 days gestational age. Thereafter, expression was increasingly limited to selected single cells or clusters of two to four cuboidal cells in the smallest ducts. By the 21st postnatal day, the antigen was expressed only by type II alveolar epithelial cells. Type II alveolar epithelial cells isolated from adult lung and the L2 cell line in culture expressed the antigen on the cell surface. A protein of approximately 146,000 Mr was isolated by immunoadsorption of the antigen from non-ionic detergent extracts of type II cells and L2 cells. Preliminary studies of the binding of the antibody to other rat tissues indicate that the antibody binds to renal proximal tubular epithelial cells of the kidney and the luminal surface of the small bowel epithelial cells.

Cytomegalovirus ureteritis as a cause of renal failure in a child infected with the human immunodeficiency virus.

Cytomegalovirus (CMV) infection is common in patients infected with human immunodeficiency virus. Hemorrhagic cystitis and tubulointerstitial nephritis have been recognized as complications of CMV infection, and these complications lead to hematuria and compromised renal function. We describe a case of CMV infection of the ureters in a child with vertically acquired human immunodeficiency virus infection; the child presented with severe suprapubic pain, and prolonged macroscopic hematuria and intermittent acute renal failure developed subsequently.

Monoclonal antibody isolation of type II pneumocytes.

A monoclonal antibody that identifies a membrane molecule unique in rat lung for type II alveolar epithelial cells was used to isolate these cells from enzymatically dispersed lung cells by fluorescence-activated cell sorting. Although multistep physical separation techniques have permitted the isolation of large quantities of these cells and flow cytometry has been used by others to isolate lamellar body-containing cells, the application of this antibody-directed sorting has distinct advantages. Because the marker molecule is expressed on immature type II cells prior to the development of lamellar bodies, the antibody will also permit their isolation and study.

Pathology of an experimental extradural spinal T cell tumor.

Syngeneic mice injected intravenously with a T cell tumor line (line 13) induced by Gross' murine leukemia virus developed paraparesis and sensory loss below the midthoracic level 2 to 3 weeks after inoculation. Although signs of systemic disease coexisted, the animals survived through the development of the neurologic symptoms, and treatment with cytotoxic agents was not required. Pathologic study of the spinal cord and brain revealed tumoral infiltration of the meninges, confined to the extradural spaces, more markedly at spinal than cerebral levels. Equally severe infiltrates occurred in the paravertebral musculature. No leptomeningeal or parenchymal involvement was present, irrespective of the severity of the extradural infiltration. Marked bone marrow and visceral infiltration coexisted with central nervous system involvement. The topography of the extradural and muscular tumor cells collections related to the proximity of the involved bone marrow and areas of direct communication between these spaces were repeatedly identified. On the other hand, line 13 cells injected directly into the brain substance produced diffuse leptomeningeal tumoral infiltration without extradural involvement. These findings suggest that the pathogenesis of this model of spinal T cell tumor proliferation involves a first stage of bone marrow infiltration, followed by extradural involvement. This occurs by direct migration of bone marrow tumor cells through gaps in the vertebral bone. This model offers the opportunity for the study of malignancies that produce bone destruction as a mechanism for tumoral spread.

Treatment of established lung metastases with tumor-infiltrating lymphocytes derived from a poorly immunogenic tumor engineered to secrete human TNF-alpha.

The growth of a poorly immunogenic methylcholanthrene (MCA)-induced murine (m) sarcoma genetically engineered to secrete human (h) TNF-alpha (MCA-102-hTNF) was studied. MCA-102-hTNF tumor cells were implanted in animals bearing three- or 7-day pulmonary metastases established with the parental line MCA-102-WT (wild type). This model approximates the clinical situation in which patients with metastatic cancer would be vaccinated with autologous tumor genetically modified to stimulate the host immune response. Reduction in the number of pulmonary metastases was occasionally seen but was not consistently reproducible. Other cytokine-producing tumors had either no effect on distant pulmonary metastases (mIL-4, IFN-gamma) or a mild, inconclusive effect similar to hTNF-alpha (mTNF-alpha). Significant growth inhibition of MCA-102-hTNF was noted in animals bearing pulmonary metastases. This inhibition was: 1) tumor specific (regression occurred only in animals bearing pulmonary metastases from the same parental line), 2) TNF specific (it was inhibited by in vivo administration of anti hTNF mAbs), 3) dependent on cellular immunity (immune-depletion with anti-CD4 or CD8 mAbs permitted growth). Tumor-infiltrating lymphocytes (TIL) could not be grown from MCA-102-WT or MCA-102-hTNF tumors nor from MCA-102-WT subcutaneous implants in mice bearing MCA-102-WT pulmonary metastases. However, TIL could be grown from hTNF-secreting tumors implanted in mice bearing MCA-102-WT metastases. These TIL were therapeutic against established lung metastases from the parental tumor in adoptive immunotherapy models. These studies suggest a strategy for using gene modified tumors for the therapy of established cancer.

Defective major histocompatibility complex class I expression in a sarcomatoid renal cell carcinoma cell line.

We studied major histocompatibility complex (MHC) class I expression in 12 tumor cell culture lines established from patients with metastatic renal cell carcinoma (RCC). In one of these cell culture lines, UOK 123, we found no surface expression of beta 2-microglobulin (beta 2m) and MHC class I by flow cytometry. Immunofluorescence staining using three different monoclonal antibodies to beta 2m revealed no detectable beta 2m in the endoplasmic reticulum (ER), Golgi apparatus, cytoplasm, or on the cell surface. There was no evidence of folded class I molecules inside or on the surface of the cells; however, the ER stained intensively for unfolded class I molecules. Transient expression of beta 2m by UOK 123 after infection with a recombinant vaccinia virus containing the gene for beta 2m resulted in normal expression of both beta 2m and class I (HLA-A, B, C) determinants assessed by flow cytometry analysis. No expression of class I or beta 2m was seen with the recombinant vaccinia vector carrying a control gene. The inability of class I molecules to reach the cell surface is due to the requirement of beta 2m for proper folding and presentation of the class I MHC complex. The failure to assemble and express MHC class I complex on the cell surface renders these cells incapable of antigen presentation to cytotoxic T cells and provides a mechanism for escape from immune recognition by the tumor.