Type-C virus particles in placenta of the cottontop marmoset (Saguinus oedipus).

Electron microscopy of near-term placentas of two cottontop marmosets (Saguinus oedipus) revealed, in one placenta, the presence of budding and mature C-type virus particles associated with the basal trophoblast. The particles were morphologically similar to those observed by other investigators in placentas of other primate species.

Particle--lamella complexes in a case of human benign prostate hyperplasia: brief communication.

Particle--lamella complexes (PLC's), described for the first time, were found in glandular epithelial cells of the hyperplastic prostate tissues from a patient with transitional cell carcinoma of the urinary bladder. PLC's observed in this patient were similar to those seen in human hematopoietic neoplastic cells. They showed cylindroid forms and were composed of concentrically arranged lamellae and particles found in rows between these lamellae. PLC is closely related to rough endoplasmic reticulum (RER), and some PLC's were completely surrounded by RER. Particles approximately 25--30 nm in diameter were similar to ribosomes in size, shape, and electron density; lamellae approximately 10 nm thick appeared circular in cross sections and lamellar in longitudinal sections. Although the nature and function of PLC's are as yet unknown, the present observation indicated that PLC's are not a characteristic structure restricted to malignant tumors of hematopoietic origin.

Virus-like particles in a case of human prostate carcinoma.

Two morphologically different types of intracisternal virus-like particles were observed electron microscopically in a biopsy specimen of human prostate cancer. Particles of one type were 150-200 nm in diameter and contained either an electron-dense core or two concentric inner layers. Particles of the other type were smaller, 80-100 nm in diameter, and appeared mostly in filamentous or chainlike formation. Both types of particles and budding were observed in endoplasmic cavities of epithelial tumor cells. The particles had ultrastructural characteristics that suggested a viral nature but were different from the known type B, type C, or type H (hamster type R) virus particles. This was the first election microscopic observation in prostate cancer of virus-like particles similar to those previously reported in a case of human breast carcinoma.

Sarcoma-negative leukemia-positive transformed cell culture established from a murine sarcoma virus-induced rat bone tumor.

Inoculation of the Soehner-Dmochowski isolate of the Moloney strain of murine sarcoma virus (MSV), designated MSV-SD, consistently leads to the development of bone tumors in the susceptible New Zealand black (NB) rats. Two separate cell cultures have been established from 2 individual MSV-SD-induced NB rat bone tumors. Cells of 1 bone tumor culture, designated RBT-E, are in early in vitro passages. These cells form colonies in agar medium and take up 2-deoxy-D-[3H]glucose at a greatly enhanced rate, 5 times that of normal nontransformed rat embryo cells. Cells of the RBT-E culture release both MSV and murine leukemia virus (MuLV) and therefore contain sarcoma-positive leukemia-positive transformed cells. The other rat bone tumor culture, designated RBT-L, produced MSV at early passages. RBT-L culture has been passaged over 130 times in vitro. Cells of the RBT-L culture form colonies in agar medium and take up 2-deoxy-D-[3H]glucose at an enhanced rate (3 times that of rat embryo cells), indicating the presence of transformed cells within the RBT-L culture. However, cells of the RBT-L culture at late passages (Passage 130 or more) produce only MuLV and no detectable MSV activity (as shown by the lack of tumor-inducing activity and the lack of focus-forming activities by direct assay or by infectious center assay). Attempts to rescue MSV activity from RBT-L cells by cocultivation with MuLV-producing mouse cells were not successful. The MuLV found in the RBT-L cells, however, is a competent helper virus capable of rescuing the MSV genome from MSV-SD-induced hamster bone tumor cells. All the available evidence supports the notion that late passages of the RBT-L culture contain transformed cells that do not produce conventionally detectable MSV. These cells are referred to as sarcoma-negative leukemia-positive cells. The sarcoma-negative leukemia-positive cells represent a different kind of MSV-induced transformed cells and provide a unique system for studies in search of MSV markers such as MSV-specific antigens and MSV-specific nucleotide sequences.

Immunoelectron microscopic studies of antibodies in mouse sera directed against mouse mammary tumor virus.

Indirect immunoferritin and fixed immunofluorescence tests were carried out on (a) sera of mice hyperimmunized with isologous mouse mammary tumor virus (MMTV) particles or isologous MMTV-producing mammary tumor cells grown in tissue culture and (b) sera of mammary tumor-bearing and tumor-free mice of several inbred strains. Sera were tested against MMTV produced by C3H/HEJ/Tex tissue culture cells (MMT-1). Mammary tumor-bearing A/Dm, C3H/HeTex, and RIII/Dm mice and apparently tumor-free A/Dm mice were found to develop naturally occurring nonprotective anti-MMTV antibodies, whereas sera of tumor-free C3H/HeTex, RIII/Dm, and C57BL/6/Tex female mice and A/Dm, C3H/HeTex, and RIII/Dm male mice did not contain anti-MMTV antibodies. Indirect immunoferritin and fixed immunofluorescence labeling of MMTV particles was prevented by absorbing sera with purified MMTV particles. The results demonstrate the relationship of naturally occurring anti-MMTV antibodies in mouse sera to the presence of mammary tumors, confirm previous reports that mice are not tolerant to MMTV, and further establish the usefulness of the indirect immunoferritin procedure in studies of the immune response of mice.

Electron microscopic studies of intracisternal virus particles in Soehner-Dmochowski murine sarcoma virus-induced bone tumors of New Zealand Black rats.

Soehner-Dmochowski murine sarcoma virus (Moloney)-induced bone tumors of New Zealand Black rats carry two morphologically different types of virus particles, namely, extracellular type C and intracisternal virus particles, which have thus far not been reported. These two types of virus particles have also been observed in the tissue culture cells derived from normal prostate tissues of A/Dm and BALB/c/Dm mice after inoculation of cell-free extracts of these bone tumors. The intracisternal virus particles, 90 to 120 nm in diameter, have always been found in the rough endoplasmic reticulum; they have two inner concentric layers with a relatively electron-lucent center, frequently showing cylindrical, chain-like, or multipolar budding forms. Type C virus particles produced by Soehner-Dmochowski murine sarcoma virus (Moloney)-infected prostate tissue culture cells from A/Dm and BALB/c/Dm mice belong to the murine sarcoma-murine leukemia virus group, as revealed by the fixed immunofluorescence test and by immunoelectron microscopy. The morphological and immunological relationship of intracisternal virus particles and other types of virus particles (such as type C, type H, and intracisternal type A virus particles) and intracisternal virus particles in guinea pig leukemia are defined by routine electron microscopy observations and by immunoelectron microscopy studies.

Implications of humoral antibody in mice and humans to breast tumor and mouse mammary tumor virus-associated antigens.

As a part of a program directed toward the elucidation of the role of viruses in mouse and human breast cancer, a variety of immunological techniques were applied to a study of the humoral immune response of mice and of humans to their breast tumors. Tumor-bearing mice were found to produce antibodies against a complex array of tumor cell-associated antigens, including mouse mammary tumor virus (MMTV), components, heterophile and Forssman-like antigens, embryonic antigens, and possibly other tumor-associated antigens. Mice bearing MMTV-positive tumors had high titer antibodies against both viral and heterophile antigens. Tumor-free mice, whether of high or low mammary cancer strains, were remarkably free of antibodies that could label MMTV particles, although some sera contained antibodies to viral components. Patients with breast cancer also had antibodies against a variety of antigens associated with their own and homologous breast cancer cells. These antibodies reacted with heterophile, embryonic, and other tumor-associated antigens, some of which appeared to be viral. Sera of some patients with breast cancer gave positive immunofluorescence reactions with mouse mammary tumor cells grown in tissue culture and producing MMTV. Most of these reactions were due to heterophile antibodies in the sera, but a small number of sera contained antibodies apparently directed specifically toward MMTV particles, as determined by immunoperoxidase electron microscopy. Although human-mouse cross-reactions must be interpreted with caution, these data suggest that a virus putatively associated with human breast cancer is antigenically related to MMTV.

In situ embedding method of cells grown in beem capsules for immunoelectron microscopic studies of oncornaviruses.

A technique of in situ embedding of cells grown in BEEM capsules has been devised for immunoelectron microscopic studies of oncornaviruses. As compared to other immunoelectron microscopic procedures, this technique is less time and reagent-consuming. The quality and specificity of this method were tested on well-characterized mouse mammary tumor virus (type B virus) and murine sarcoma virus (type C virus particles). This method gave good results in labeling of the virus particles with ferritin or peroxidase in the cells of mouse tissue cultures. In an application of this method, peroxidase labeling of type B virus particles was obtained in frozen sections of normal prostatic tissues of C3H/Dm and A/Dm strain mice treated with rabbit antiserum to mouse mammary tumor virus from A/Dm strain mouse milk. These results indicate that this method is useful and reliable for immunoelectron microscopy studies of oncornaviruses in tissue culture cells and also in frozen sections of tissues.

Viral type A and type B hepatitis: morphology, biology, immunology and epidemiology--a review.

Viral hepatitis is one of the most serious infectious diseases in the United States and is of great concern to the public health agencies, hospitals and research laboratories. Progress in our knowledge of this disease has been based on cooperation between specialists in many diverse scientific disciplines employing sophisticated scientific instruments and technics. Close cooperation between clinical pathologists and clinicians is of great importance in diagnosis. Biologic, immunologic, epidemiologic and morphologic studies have resulted in the demonstration that the disease is the result of infection with at least two different viruses, described as type A and type B hepatitis viruses. The first induces type A hepatitis (infectious or epidemic, or MS-2 strain) of longer incubation period, is transmitted parenterally and apparently by inhalation or ingestion of virus-containing material, by venereal means as well as by other means. Extremely sensitive methods are now available for the detection of hepatitis type B infection, based on the results of biochemical, biophysical and immunoelectronmicroscopic studies that resulted in our knowledge of structure and composition of type B virus, and our knowledge of host immune responses to the various components of this virus. Thus it is now known that two antigen-antibody systems are associated with viral hepatitis type B: hepatitis B surface antigen (HBsAg) and antibody (HBsAb) and hepatitis B core antigen (HBcAg) and antibody to it (HBcAb). The test for antibody to HBcAg appears to be a sensitive indicator of viral replication when only subdetectable amounts of HBsAg are circulated. Since the recent discovery and characterization of type A hepatitis virus, great progress has been made in our understanding of the relationship between type A and type B hepatitis viruses. There is no cross immunity between the two viruses, and as is now suspected, there may be at least another virus, described as type C virus, which may play an etiologic role in viral hepatitis. There is no doubt now that type A and type B hepatitis viruses can be transmitted to monkeys; type A to marmosets and chimpanzees, type B to chimpanzees and rhesus monkeys. The two viruses are serologically and immunologically distinct. This knowledge and the results of biologic experiments have laid a solid foundation of meaningful diagnostic procedures for the two types of viral hepatitis. Advances in biophysical and biochemical procedures of treatment of sera of hepatitis B patients have resulted in availability of viral material, noninfectious but immunogenic, for vaccination of chimpanzees. Protective efficacy trials of the vaccine in chimpanzees have demonstrated the vaccine to be fully protective against high doses of infectious hepatitis B virus...

Morphological, biological, immunological and biochemical studies on bone tumors of animals and man.

Biological studies on FBJ osteosarcoma virus in tissue cultures have led to the isolation of murine sarcoma virus. Characteristic type C-MuLV particles were observed in bone tumors induced by the SD-MSV-M-virus in vitro and in vivo. The SD-MSV-M virus also induced bone tumors in rats of all strains tested, and it has a similar tumor-inducing property in hamsters. Immunoelectronmicroscopic studies showed that envelope antigens of MSV-SD virus in rat bone tumors can be distinguished from those found in hamster bone tumor cells. In tissue cultures of MSV-SD rat bone tumors, two separate cell lines have been established: one of them releases both MSV and MuLV and the other produces MuL virus only. The MuLV in this cell line acts as helper. The different interactions appear to support the concept of control mechanisms for the partial expression of genes which are responsible for neoplastic properties, virus replication, and synthesis of gs-antigens. Biochemical studies on structural rearrangement and subunit composition of RNA released from MSV-SD virus, have shown that there are two forms of the native genome RNA differing in their sedimentation coeffiiecients and in subunit composition. In human osteosarcoma tissue culture, type-C viruslike particles are found. In cocultures derived from human osteosarcoma with cells taken from the bone marrow or peripheral blood of patients with different types of leukemia, certain morphological changes are observed which resemble those induced in animal cells by RNA tumor viruses. In osteosarcomas where no cytoplasmic antigen could be proved by an immunofluorescence test, the antigen could be produced by cocultivation with antigen-positive leukemic bone marrow cells. Whole human embryo cells treated with fluid from leukemia bone marrow cultures showed the presence of the cytoplasmic antigen when tested with positive sera, but they showed no morphologic changes. In high molecular weight RNA species, sedimentation coefficients ranging from 62S to 68S are demonstrated by molecular hybridization techniques. In cross-hybridization experiments, annealing values were observed only with complementary DNA products synthesized from sarcoma viruses. Three particularly high molecular weight RNA species released from human sarcoma cell cultures showed no cross-hybridization with either the DNA product of Rauscher leukemia virus or that of Gross leukemia virus.