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Biomedical subjects

M F Woodruff

Publications and source records attributed to M F Woodruff.

At least 19 recordsLinked to original sources

Oligoclonal tumours.

Tumours are commonly classified as monoclonal or polyclonal. The question of how many clones are present in a polyclonal tumour is seldom asked; it is important, however, because the answer may show whether or not clones arise and develop independently, and whether the number of clones in tumours of a particular kind tends to increase or decrease with time. We have used two procedures to assess the clonality of chemically-induced murine fibrosarcomas, one based on the heterozygosity of the tumour hosts for an X-linked marker, the other on the expression of tumour-associated transplantation antigens (TATA) by the tumours. As we have reported previously, many of these tumours are pleoclonal. Evidence now presented suggests that the clones do not develop independently and that many of the tumours are biclonal.

Animals

The cytolytic and regulatory role of natural killer cells in experimental neoplasia.

NK cells are defined here as cells, other than macrophages and polymorphonuclear leucocytes, from non-immunized animals (or humans) which are cytotoxic for neoplastic and non-neoplastic targets in the absence of specific antibody. Though not requiring antibody, they may function as K cells in ADCC. This definition includes cells activated nonspecifically by such agents as IFN and IL-2. Murine NK cells may be subdivided into two types by differences in the kinetics of target-cell lysis. Those we label Type 1 correspond roughly to what others have called NKA, NKL or simply NK cells; those of Type 2 to NKB, NKS and NC cells. Type 1 cells express various antigens, including NK-1, Thy-1 (50%), Ly-1 (25%), Qa-3, Qa-4, Qa-5, Ly-5, Ly-6, Ly-10, Ly-11 and asialo-GM1, not expressed by Type 2 cells, whereas Mac-1 may be expressed by both types. At least some NK cells appear to be pre-thymic cells which, in the presence of a thymus, can differentiate into T cells. The level of NK activity is influenced by the age and genetic background of the mouse, the organ from which the cells are obtained, and a variety of experimental manipulations. Type 1 activity is increased by IFN and IL-2; Type 2 activity by IL-3. IFN appears to be concerned in the development of spontaneous NK activity in young mice. Many experiments have shown that NK cells may inhibit the growth of tumours which are sensitive to NK cells of the same type in vitro. Inhibitory cells which suppress NK activity may play an important regulatory role in vivo. There is still uncertainty about how NK cells recognize their targets. Possibilities discussed are: (1) specific interacting molecules; (2) more diffuse properties of target cell membranes; (3) absence of MHC-coded self-recognition markers. Certainly, the presence of a Class 1 MHC molecule is not necessary. NK killing appears to be mediated by cytotoxins released by NK cells. In vivo, NK cells contribute to limiting the development of transplanted and primary tumours, and metastasis from established tumours. NK cells seem well qualified to act as a first-line defence against neoplasia, and may kill cells not killed by T cells. Transfer of NK cells may be of value in the treatment of cancer.

Age Factors

The effect of passage in vivo and in vitro on the properties of murine fibrosarcomas: III. Cell surface molecules and production of growth factors.

Three factors may be responsible for the sharp difference in tumourigenicity between cloned murine fibrosarcoma lines maintained in vitro, and cells of the same lines after in vivo passage, initially in a T cell deficient mouse and subsequently in normal mice: acquisition during passage of resistance to NC cells; acquisition during passage of a surface molecule, probably a sialic acid, which protects the cell against T cell-mediated lysis; and ability of the passaged cells, but not the non-passaged cells, to produce sufficient amounts of autocrine growth factors necessary for growth in vivo. The tumourigenicity of the passaged cells cannot be attributed to failure to express TATA or MHC class I molecules.

Animals

The effect of passage in vitro and in vivo on the properties of murine fibrosarcomas I. Tumorigenicity and immunogenicity.

Cloned cell lines of chemically-induced murine fibrosarcomas maintained in tissue culture usually fail to grow when transplanted to normal syngeneic mice. They grow, however, in various categories of T cell deficient mice and after such passage grow readily in normal mice. Both cultured and mouse-passaged lines possess strong TATA. Three alternative explanations are suggested which might account for these findings. Emergence during the initial passage of a population of tumour cells resistant to NC cells. Acquisition during the initial passage of a protective surface molecule that interferes with the efferent side of the immune response when the tumour cells are subsequently transplanted to a normal host. Loss during the initial passage of a Class I MHC molecule which prevents dual recognition of the tumour cells by T cells when they are transplanted to a normal host. New experiments are proposed to distinguish between these possibilities.

Animals

Studies with a spontaneous mouse tumor. I. Growth in normal mice and response to Corynebacterium parvum.

Growth of isogeneic transplants of a spontaneous murine adenocarcinoma, which is virtually devoid of tumour-specific transplantation antigens, is inhibited by i.v. injection of C. parvum 3 days after tumour inoculation, or by mixing a small dose of C. parvum with the tumour inoculum. Moreover, the therapeutic effect of cyclophosphamide, followed by i.v. or i.p. injection of C. parvum 5 days later, on established transplants of the same tumour is greater than that of cyclophosphamide alone. These findings are consistent with the hypothesis that in both situations (i.e. before the appearance of a palpable tumour and after reduction of an established tumour transplant with cyclophosphamide) the effect of C. parvum is largely due to activation of macrophages or macrophage precursors. They have the important practical implication that adjuvant therapy with C. parvum may be of value, even with tumours which are devoid of TSTA.

Adenocarcinoma

Inhibition of the growth of lymphoid tumours in syngeneic athymic (nude) mice.

A comparison of the growth of a number of BALB/c tumours in BALB/c, BALB/c.nu/ + (heterozygous nude) and BALB/c.nu (homozygous) nude mice has shown that a majority of BALB/c lymphoid tumours grow at a significantly reduced rate in BALB/c.nu mice. The three non-lymphoid BALB/c tumours (carcinomas and sarcomas) tested and a minority of lymphoid tumours, however, grew as well, or better, in the BALB/c.nu mice. Furthermore a correlation, without exception to date, has emerged from a comparison between the susceptibility of a tumour cell line to in vitro lysis by spleen cells from syngeneic nude mice and its growth in vivo in syngeneic nude mice. Only those lymphoid tumour cell lines lysed in vitro show the reduced growth rate in syngeneic nude as compared to syngeneic normal mice. Tumour cell lines, both lymphoid and non-lymphoid, which are resistant to in vitro lysis do not show the reduced in vivo growth rate in syngeneic nude mice. Both the in vivo and in vitro effect can be partially abolished by irradiating the nude mice prior to use, suggesting that a radiation-sensitive non-T-cell surveillance of lymphoid tumours is operating in nude mice. While the identity of the antigens is still unknown, the specificity of the phenomena suggest that C-type RNA oncogenic viral determined antigens are involved.

Animals

Effect of Corynebacterium parvum on tumor growth in normal and athymic (nude) mice.

The effect of systemic or local injection of Corynebacterium parvum at the tumor site on the growth of various murine tumors was studied in intact and congenitally athymic BALB/c mice. Systemic injection of C. parvum usually had a marked antitumor effect in both types of mouse. Two lymphomas, which regressed spontaneously in untreated intact mice but not in athymic mice, grew progressively in intact mice given systemic C. parvum, though their growth was inhibited in similarly treated athymic mice. Local injection into the site of the tumor markedly inhibited tumor growth in intact mice but was without effect in athymic mice. C. parvum was believed to exert its antitumor effects by two different mechanisms, only one of which was T-cell dependent. The mechanism not dependent on T-cells was particularly activated by systemic C. parvum injection.

Animals

Modification of the effect of C. parvum on macrophage activity and tumour growth by X-irradiation.

The radiosensitivity of three forms of response to injection of C. parvum in mice has been investigated. The increase in phagocytin index evoked by IP or IV injection of 0.7 mg C. parvum (but not that evoked by 1.4 mg) was reduced but not abolished in mice given 350-500 rad whole-body irradiation 4 days before C. parvum injection. Irradiation (500-1,000 rad) 4 days after C. parvum injection had no such effect. The antitumour cytotoxicity in vitro of PE and spleen cells from C. parvum-treated mice was abolished by irradiation of the cell donor (400-800 rad) 4 days before C. parvum injection, but was not reduced by irradiation (800 rad) of the cell donor 4 days after C. parvum injection or of the effector cells in vitro. The antitumour response to systemic (IP) injection of C. parvum was reduced by 350-500 rad whole-body irradiation, irrespective of whether this was given 4 days before or 4 days after C. parvum injection. The response to intratumour injection of C. parvum was even more radiosensitive. It has been suggested in previous papers from this laboratory that the antitumour effect of C. parvum is related to its capacity to stimulate macrophage activity, although in addition T lymphocytes are necessary for local injection to be effective and non-T lymphocytes may be concerned in the response to both local and systemic injection. The present results in no way conflict with this view. They suggest in addition that the effect of C. parvum on the macrophage system is, to a considerable extent, due to stimulation of macrophage precursors to differentiate into actively phagocytic and cytotoxic mature cells.

Animals

Long survival after renal transplantation in man.

The indications for transplantation, complications, management and results in 127 consecutive patients who had received renal transplants between October 1960 and December 1974 are presented. In 2 cases the donor was an identical twin, in 22 a living relative other than a twin, in 2 an unrelated individual in whom nephrectomy was performed for therapeutic reasons and in 101 a cadaver. At the end of the period under review there were 37 patients alive with grafts which had functioned for 6 months or more; of these, 28 had survived for more than 2 years, 13 for more than 5 years, 6 for more than 8 years and 2 for more than 12 years. Thirty-four patients were employed or doing routine housework or receiving full-time education. One patient fathered a child 4 years after transplantation; another gave birth to a healthy infant 3 years after transplantation.

Adolescent

Effect of C. Parvum on immunization with irradiated tumour cells.

S.c. injection of tumour cells or small pieces of tumour irradiated to a dose of 22,000 rad evoked resistance to live challenge with the same tumour (a CBA strain fibrosarcoma induced with methylcholanthrene) 14 days later. This resistance was, however, over-ridden if the challenging inoculum was sufficiently large, and did not develop if the cells were irradiated to 100,000 rad. The resistance evoked by injection of 10(6) irradiated tumour cells was impaired by i.p. injection of 1-4 mg C. parvum 5 days before, and virtually abolished by a similar injection 11 days after, the irradiated cells. The effect of s.c. injection of a mixture of 10(6) irradiated cells and C. parvum 14 days before live challenge depended on the dose of C. parvum. With 0-7 mg the development of resistance was largely but not completely abrogated; 0-35 mg resulted in a lesser degree of abrogation, and 0-09 mg or 0-02 mg had little or no effect.

Animals