Enhanced lymphoma incidence in BALB/c mice after ultraviolet light treatment

Following UV irradiation of BALB/c mice three times a week for 9 months, lymphatic leukemia or reticulosarcoma developed in 44 (12%) of 378 mice whose backs were shaved and whose ears were intact. Only 11 (5%) of 224 UV-irradiated mice whose backs were shaved and whose ears were removed developed lymphomas. Among 311 unirradiated mice whose backs were shaved, 9 lymphomas (3%) occurred. The diagnosis of leukemia or reticulosarcoma was confirmed by microscopy and transplantation. Among irradiated mice, ear tumors developed in 24% of the mice with intact ear, whereas skin tumors developed on the shaved backs in 4% of the mice whose ears were removed and also in 4% of the mice with intact ears.

Inhibitory effect of a revertant cell on in vivo growth of its parental transformed cell line

A revertant cell line, KSR-4111, cloned from a sarcoma virus transformed non-virus producing murine 3T3 cell line, K-BALB-23, was found to inhibit in vivo growth in newborn syngeneic mice of the transformed cells when grafted to the same locus, but not when grafted separately from the grafted tumor cells. No inhibition of outgrowth of the transformed K-BALB-23 cells was obtained with another revertant, KSR-12121, also cloned from the transformed K-BALB-23 cell, nor with the normal 3T3 cell. Furthermore, grafting of two syngeneic mammary tumors was unaffected by the presence of the protective revertant cells. The protective revertant KSR-4111 was furthermore characterized by inducing cytoxic non-theta-antigen-bearing spleen lymphocytes in grafted syngeneic recipients.

In vitro susceptibilities of normal human skin fibroblasts to oncoviruses, and the decreased susceptibility to HSV of fibroblasts from untreated Hodgkin's patients

Fibroblast cultures established from the skin of 56 healthy controls and 15 untreated Stages I and II Hodgkin's patients (HD) were studied in their 3rd, 4th and 5th in vitro passage with respect to transformation with Simian sarcoma virus (SSV) and SV40 and with respect to replication of herpes simplex virus (HSV) Types 1 and 2, pox virus and interferon release. Susceptibility to the 5 viruses varied independently, except for an inverse correlation between susceptibility to SSV and HSV. HD cultures showed a depressed replication of both types of HSV. There was a borderline (P = 0.02) correlation between magnitude of HSV replication and presence of HL-A type B-w44, but this does not explain the HD control difference. Furthermore, the level of serum antibodies to HSV common antigen was not related to magnitude of in vitro replication. The results thus speak against generally enhanced cellular susceptibility to HSV as a reason for the high titres of serum antibodies to HSV in HD patients.

Stimulatory effect on DNA synthesis of thymus and spleen extract from leukemic AKR mice

A 30,000-50,000 molecular weight (MW) extract of thymus and spleen from 11 age groups of untreated AKR mice, 1-210 days old, was tested for in vitro effect on thymidine incorporation into normal AKR lymph node cells, normal spleen cells, and leukemic thymocytes. Extracts from mice up to 5 months of age mostly had slightly inhibitory effect but concomitant with emergence of thymus leukemia in the 6-month-old mice, the extract acquired a strongly mitogenic effect on normal lymph node cells. Seven-month-old, non-leukemic animals again yielded extracts with inhibitory effect.

Epidermal carcinogenesis in young and aging animals

1) There is an enhanced susceptibility to carcinogen in senescent mouse skin which we believe should cause deliberations about safety regulations for humans; 2) both accumulation of variant cell and/or change in a local mitosis regulatory system should serve as working hypothesis for further studies.

Elevated titer of antibodies to Simian sarcoma virus envelope antigen (gp70) and normal response to influenza virus in untreated Danish Hodgkin's patients

Untreated Danish Hodgkin's disease (HD) patients and paired age- and sex-matched controls were tested for serum antibodies to Epstein-Barr virus (EBV), six strains of influenza virus and Simian sarcoma virus/Simian sarcoma-associated virus [SSV(SSAV)] antigens. HD sera showed significantly elevated titers against EBV and both increased incidence and mean titer of antibodies to the envelope glycoprotein of SSV(SSAV), whereas testing against the influenza viruses revealed no differences between HD and controls. A focus reduction assay demonstrated a low incidence in HD and controls of sera with neutralizing effects against SSV(SSAV) and the "baboon" C-type virus component of the human HL-23 virus complex, which seemed coupled to HL-A type W19.

Arrest of cell membrane movements by in vitro incubation with polycation reversed by polyanion

A total arrest of cell membrane movement occurred after incubation for 2 h of cultured fibroblasts with the polycation DEAE-dextran. The immobilized cells resumed normal membrane undulations after exposure for 5 min to the polyanion dextran-sulphate. The influence of DEAE-dextran on the electrophoretic mobility, which was seen after 10 min of incubation was also erased by a subsequent incubation with dextran-sulphate. No influence on growth of the culture was seen.

Natural polyclonality of spontaneous AKR leukemia and its consequences for so-called specific immunotherapy

Young female AKR mice made leukemic by iv inoculation of 10(3) spontaneous AKR thymoma cells were treated with repeated injections of irradiated cells from the same tumor. Treatment began 1 day after injection of the viable cells. The cytotoxicity of sera and lymphoid cells from healthy mice immunized with lymphoma cells from either treated or nontreated mice with leukemia grafts revealed that the tumor cells could be subdivided into four distinct antigenic types. One type (clone A) accounted for about 97% of the lymphoma cells in each mouse with spontaneous leukemia, whereas the remaining 3% were subdivided into three other distinct antigenic types (clones B, C, and D). Lymphoma cells from treated mice with grafted leukemia were never clone A type but either clone B, C, or D type. Repeated sc injections of 10(7) irradiated cells from spontaneous AKR thymomas induced from 15 to 34% cure in mice with grafts of leukemia cells. Treatment with only clone A induced about 32% cure, whereas treatment with clone B, C, or D had no beneficial effect. Treatment with 10(7) cells each of clone A plus clone B gave 33% cure; clone A plus clone B plus clone C, 45%; and all four clones cured 92% of the mice with leukemia grafts. The efficiency of immunotherapy may be influenced by the natural clonality of the tumor to be treated.

Immunoadjuvant treatment of primary grafted and spontaneous AKR-leukemia. I. Treatment efficiency correlated to autoimmune reactivity

Young AKR mice grafted i.v. with 10(1) or 10(3) cells from spontaneous AKR thymomas were treated with repeated i.v. injections of BCG or subcutaneous injections of irradiated AKR thymoma cells. BCG often cured mice from graft leukemia, whereas the effect of irradiated thymoma cells was less effective. Mice that did not develop graft-leukemia after graft of 10(1) leukemia cells and BCG treatment showed a spontaneous leukemia in 30% of the cases later. Ninety percent of nongrafted mice developed spontaneous leukemia whether BCG-treated or not. General immune reactivity as assessed in individual mice by T and B lymphocyte mitogen tests as well as the hemolytic plaque-forming cell assay had no clear correlation to the effects of immune adjuvants in respect to survival. In contrast, occurrence of self-directed immune reactions were clearly correlated to survival and cure of grafted and BCG-treated mice as revealed by assays both in vitro and in vivo. However, 13 to 25% of the mice apparently cured of leukemia developed a wasting-like syndrome that sometimes terminated in death. The immplications of self-directed immune reactions as mediators of the anti-neoplastic effects of immunoadjuvants.

Specificity of the inhibition of DNA synthesis by extracts from cloned normal, sarcoma-virus-transformed and revertant 3T3 cells

Extracts containing tissue-specific DNA-inhibitory activity were prepared from normal FL (Swiss) and BALBc3T3 cells, from these cells transformed with sarcoma virus and from revertants cloned from the transformed cell lines. By testing all extracts on all cell lines we found that (1) production of and susceptibility to the inhibitors were decreased in transformed BALB/c cells (2) specificity varied with expression of the transforming genome, as an extract from a given cell line inhibited the growth of its cell of origin, e.g. revertant, more than normal or transformed cells, and (3) there was also a DNA-synthesis stimulator.

Effect of tissue specific mitotic inhibitors on survival time of spontaneous and virus-induced murine leukaemia and influence on myocardial degeneration

Treatment of adult AKR mice with tissue-specific mitotic inhibitor mol. wt. 1,000--20,000 extracted from the AKR thymus significantly delayed the onset of spontaneous thymus leukaemia, whereas extracts of other organs were without effect. A slight prolongation of survival time was found with spleen extract when administered to BALB/c mice infected with Rauscher virus, which causes leukaemia starting in the spleen. Thymus extracts of MW 100,000--300,000 caused myocardial degeneration in some leukaemic and nonleukaemic mice.

Experimental induction of tumor growth control by immune adjuvants: current status and some theories to be explored

Immune adjuvants have been shown to induce tumor growth control in many experimental tumor-host models. The beneficial effect depends on tumor size and type and dose of the adjuvants in question, but few experimental data elucidate, which immunological mechanisms--if any--that are directly involved in the tumor destructive processes induced by immuno-adjuvants. The importance of non-specific tumor immunity is discussed with emphasize on the importance of immuno-competent cells that react non-specifically, and that may include "self-directed" cells. Non-immunological mechanisms are proposed also to be of importance, underlining the possible role of the phenomenon of spontaneous reversion of malignant cells to a non-malignant state. It is finally stressed that both immunologic and non-immunologic properties of immunoadjuvant induced tumor growth control must be analysed before therapy with immunoadjuvants can be optimally applicated in the cancer patient.

Life span, leukaemia and amyloid incidences of untreated and polycation-treated AKR mice

AKR mice, which have a short mean survival time and usually die with leukaemia, were studied from one month of age for correlation between these two parameters. For untreated animals we found the same mean survival time whether or not leukaemia occurred. By treating sucklings with the polycations diethylaminoethyl-dextran or hexadimethrine bromide the leukaemia incidence was significantly reduced. However, the mean survival time was unchanged, and remained the same in leukaemic and non-leukaemic animals. It is therefore suggested that the early death of AKR mice results from an ageing process and does not require leukaemia for implementation. Our prophylactic polycation treatment was furthermore found to induce spleen amyloid in some but not all of the mice that remained non-leukaemic.

Correlation between polyion effect on cell susceptibility to in vitro infection with murine C-type viruses and polyion effect on some membrane-related functions

Polyions were tested for effects on some membrane-related functions. Both polycations investigated reduced the negative surface charge of assay cells and enhanced in vitro infectivity of murine C-type viruses, but had no influence on leukemia-virus-induced XC cell syncytia formation. Three polyanions increased the net outer cell charge, while only one of four inhibited infectivity and two of three impeded syncytia formation. Polyions had a slight, probably toxic, effect on the transmembrane potential, independent of their charge. Cells treated with fluorescent DEAE-dextran showed diffuse staining, which 4 h later had been modified into a granular fluorescence with unstained areas now present. This change correlated with a loss of enhancement of viral infectivity. The only polyanion which inhibited viral infectivity had a strong antihyaluronidase activity, and hyaluronidase and Ca++ both increased viral infectivity. It is suggested, therefore, that polyions may in part work on virus-cell membrane interactions by influencing membrane enzymes and not necessarily by simply changing the net outer cell surface charge.

Effect of age of non-skin tissues on susceptibility of skin grafts to 7,12-dimethylbenz[alpha]anthracene (DMBA) carcinogenesis in BALB/c mice, and effect of age of skin graft on susceptibility of surrounding recipient skin to DMBA

The influence of age-dependent alterations in non-skin tissues on chemical carcinogen-induced skin papilloma development was studied by treatment with 7,12-dimethylbenz[alpha]anthracene (DMBA) of 4-month-old skin grafts sewed onto 4- and 20-month-old syngeneic recipients. Skin of 4- and 20-month-old BALB/c female mice differed in susceptibility to DMBA carcinogenesis, but the 4-month-old grafts showed the same papilloma incidence independent of the age of the recipient mice. In a different experiment, the influence of age of skin grafts on papilloma development on DMBA-treated recipient skin was studied. Fourteen- and 26-month-old skin grafts were carried by 14-month-old recipients. Grafts of those two ages are known to differ in susceptibility to DMBA carcinogenesis, but no effect of the grafts on papilloma development on DMBA-treated recipients was detectable. It was concluded that certain age-dependent differences in skin susceptibility to chemical carcinogens are solely a reflection of alterations in the skin at the site of carcinogen treatment.

A case control study on immunity to two Epstein-Barr virus-associated antigens, and to herpes simplex virus and adenovirus in a population-based group of patients with Hodgkin's disease in Denmark, 1971-73

One hundred and eighty-five patients with untreated Hodgkin's disease (HD) comprising 86% of all new cases diagnosed in Denmark over a 2-year period, were individually matched with healthy controls of the same age, sex, and social class. In comparison to controls, HD patients showed significantly elevated mean antibody titres to Epstein-Barr viral capsid antierences in mean titres were found for adenovirus common antigen. Subdivision of the patients by age, sex, social class, HL-A antigens, stage of disease and histology did not alter this pattern, except that significant case-control differences in EB-VCA titres could be demonstrated only for the nodular sclerosis and lymphocyte predominance subgroups. After 1 year of treatment, a significant rise in EB-VCA mean titre had taken place. Splenectomy seemed to promote this titre elevation. Neither the initial titres to EB-VCA and EBV-EA nor changes in titres over time were related to prognosis. The results of our study, which are more representative of a population of HD patients and controls than previously reported studies, confirm that the reported relationship between EBV and HD exists, but that the elevated EBV titres are probably not of etiologic significance in most HD patients.

Myocardial degeneration in mice treated with dibutyryl cyclic AMP and/or theophylline

Fibrinoid degeneration of myocardial fibrils was induced in BALB/c mice treated from 2 months of age with weekly injection of dibutyryl cyclic DAMP and/or theophylline. No evidence of cellular reaction or vascular occlusion was found.

Prolonged survival of AKR mice treated with the saponin adjuvant Quil A

Treatment of AKR mice with the saponin Quil A delayed their death in spontaneous leukaemia. In vitro tests did not demonstrate any influence on infection of rat cells with Kirsten sarcoma virus. Quil A in the concentration nanogram/ml doubled the mitogen response of AKR spleen cells to lipopolysaccharide.

DEAE-dextran and polybrene cation inhibition of antibody/complement mediated in vitro immune haemolysis

Preincubation of unsensitized sheep erythrocytes with 25 mug/ml of the polycations DEAE-dextran or polybrene prevented immune haemolysis. This inhibition could be reversed by polyanion. When already sensitized cells were incubated in polycation or when polycation was added to complement, less effect was found on haemolysis. Cell electrophoresis and immunoelectrophoresis showed that polycation does not prevent attachment of antibody to the cells.

Chalone-like effect abrogated by dextran sulphate and heparin polyanion pretreatment of target cells

Chalone prepared from primary BALB/c mouse embryo fibroblasts caused a 33% reduction in incorporation of tritiated thymidine in the cultures of the second in vitro passage of BALB/c embryo fibroblasts, whereas chalone prepared from thymus, skin and spleen was without effect. Pretreatment of BALB/c secondary fibroblasts with the polyanions dextran sulphate and heparin abrogated the chalone effect. The polycations DEAE-dextran and polybrene were without effect. The effect of incubation with the dextran sulphate polyanion was reversed when followed by incubation with DEAE-dextran polycation.

The effect of Rauscher and Moloney leukaemia virus on amyloid development in casein-treated CBA mice

Infection of adult CBA mice with Rauscher or Moloney leukaemia virus concomitantly with caseination significantly accelerated spleen amyloid development in irradiated, bone-marrow protected mice, but had no effect on untreated, adult thymectomized or thymectomized irradiated mice. Spleen tissue of mice infected with Moloney virus had the highest titre in the mice with accelerated amyloid development.

Influence of DEAE-dextran, polybrene, dextran and dextran sulphate on spontaneous leukaemia development in AKR mice and virus induced leukaemia in BALB-c mice

AKR mice of which more than 90% die of lymphatic thymus leukaemia, had their mean survival time increased by weekly intraperitoneal inoculation of either of the two polycations DEAE-dextran and polybrene. Administration of the neutral dextran had no effect, whereas the polyanion dextran sulphate accelerated leukaemia development.Adult BALB/c mice infected with Rauscher leukaemia virus and treated from the time of palpable spleen enlargement, showed a life prolonging effect of the polycations DEAE/dextran and polybrene, and of neutral dextran. BALB/c mice treated from the time of leukaemia infection, however, showed a life prolonging effect with polyanion dextran sulphate and also of neutral dextran.

Aging increases susceptibility of mouse skin to DMBA carcinogenesis independent of general immune status

The dependence of chemical carcinogenesis on age of target tissue was studied by repeated DMBA-treatment of mouse skin grafted from old and young syngeneic donors to young recipients. Carcinomas developed on 39 percent (1.6/41) of grafts from old donors and on 12 percent (5/41) of grafts from young donors. The incidence of nonskin lymphoid tumors was highest in male recipients bearing grafts from old donors.

Deae-Dextran and Polybrene Cation Enhancement and Dextran Sulfate Anion Inhibition of Immune Cytolysis

The polycations DEAE-dextran and polybrene enhanced the sensitivity of the dye exclusion cytotoxic test performed on mouse spleen cells, whereas the anion dextran sulfate had an inhibitory effect.

Dextran sulfate prevented the enhancing effect of the polycations when admixed before incubation of the cells and reversed the polycation effect when added after the sensitization had taken place.

The in vitro infection of fibroblasts with murine leukemia virus was largely influenced in the same way, indicating a similarity of the membrane processes involved.