The bacterial colicin active against tumor cells in vitro and in vivo is verotoxin 1.

We have identified verotoxin 1 (VT1) as the active component within an antineoplastic bacteriocin preparation from Escherichia coli HSC10 studied over two decades. Recombinant VT1 can simulate the toxicity of anticancer proteins (ACP), and the antineoplastic activity of ACP (and VT1) was abrogated by treatment with anti-VT1 antibody. Similarly, VT1 mimics the protective effect of ACP in a murine metastatic fibrosarcoma model.

Augmentation of interleukin-6 (IL-6) expression in squamous carcinoma cells and normal human keratinocytes treated with recombinant anti-neoplastic protein (ACP).

A protein purified from Eschericheri coli has previously been shown to have cytotoxic effects on neoplastic cells of several lineages both in vitro and in vivo. Accordingly, this protein has been named anti-neoplastic protein (ACP). Although ACP kills neoplastic cells by inducing apoptosis, it has negligible effects on various normal cells.

Partially purified bacteriocin kills malignant cells by apoptosis: programmed cell death.

Bacterial proteins, partially purified bacteriocin (PPB), were investigated for their selective killing of malignant cells. It is shown here that upon PPB-cell interaction DNA fragmentation starts within one hour and peaks at 6 hrs. This process requires an on-going cellular metabolism.

Further studies of the action of a partially purified bacteriocin against a murine fibrosarcoma.

We have reported previously that a partially purified bacteriocin (PPB) from Escherichia coli HSC10 is toxic to KHT cells growing in vivo as micrometastases but apparently has no activity against a tumor growing i.m. We report here experiments to investigate possible reasons for this difference.

Fluorescence assay to monitor phagocytosis by bloodclot derived polymorphonuclear leucocytes. 2. Study of patients with psoriasis and the effect of exposing leucocytes to psoriatic skin scales.

Comparisons of phagocytic parameters were carried out by a recently developed fluorescence test which is reproducible, simple and fast. Phagocytosis by polymorphonuclear leucocytes (PMNs) obtained from patients with psoriasis was compared with that of healthy individuals. Psoriatic skin scales, non-sterile and sterile, were tested for stimulatory effect on PMNs and compared with the effect of normal skin scrapings.

Fluorescence assay to monitor phagocytosis by blood-clot derived polymorphonuclear leucocytes. 1. Study of patients with diabetes and phagocytosis of different staphylococcal species.

A recently developed simple and rapid fluorescence assay of phagocytosis by polymorphonuclear leucocytes (PMNs) was used to compare the phagocytic activity of PMNs from diabetic patients and healthy people. Differences in phagocytosis have been described in these systems. Different bacterial strains were used to challenge the phagocytic capabilities of bacterial ingestion and killing for both patient and control groups.

Acute lymphoblastic leukemia of childhood monitored by bacteriocin and flowcytometry.

Bacteriocin and flowcytometric analysis of 106 blood samples from children with acute lymphoblastic leukemia were correlated with clinical stages of disease. Bacteriocins interacted selectively with malignant, and not with normal, lymphocytes causing cell cycle perturbation which was rapidly and objectively recorded by the flowcytometer. The patients were grouped as: (A) newly-diagnosed (15); (B) early induction (11); (C) remission with viral infection (7); (D) remission (64); (E) bone marrow relapsed (5); (F) extramedullary relapsed (3); (G) non-malignant pediatric controls (8).

Recognition of T-cell murine leukemia by bacteriocin (colicin); correlation with transplantation experiments.

The presence of potential murine leukemia and overt leukemia cells in various organs at different phases of leukemogenesis was demonstrated by transplantation experiments and sensitivity to bacteriocin (colicin HSC10). Such correlation was found in three experimental models: AKR mice developing spontaneous T-cell leukemia and BL/6 mice infected with radiation leukemia virus variants inducing a high or low overt T-cell leukemia incidence. The sensitivity to bacteriocin was evaluated by testing the cell cycle perturbation following in-vitro incubation of lymphoid cells with colicin (or Tris buffer as controls) monitored by flow-cytometry.

Purified colicin as cytotoxic agent of neoplasia: comparative study with crude colicin.

Purification of a bacteriocin, colicin, from Escherichia coli HSC10, is described. A 1,800 fold purified colicin was obtained and found to be an acidic polypeptide with a molecular weight of 82,000 daltons. The effect of colicin on bacterial and mammalian cells during the transition from a crude to a pure preparation is given.

Bacteriocin and flow cytometry in laboratory diagnosis of leukemic peripheral blood lymphocytes and bone marrow cells.

The bacteriocin, colicin HSC10, produced by Escherichia coli HSC10, was studied as a laboratory tool for detection and differentiation of leukemic from normal lymphocytes in human peripheral blood. Flow cytometry studies detected DNA loss in bacteriocin-affected cells by computerized histograms. Differential analysis is given for the peripheral blood of 26 individuals using bacteriocin, cytochemistry and surface markers.

Variants of an interspecies hybridoma with altered tumorigenicity and protective ability against mouse myeloma tumors.

Recent isolates of RX54-3 hybridoma cells (new cells) protect BALB/c mice against subsequent challenge with the tumorigenic myeloma parent cells used to construct this hybridoma. In contrast, hybridoma cells which have been maintained in tissue culture for long periods of time (old cells) are not protective. In the present study, we compared a number of properties of the new and old hybridoma cells and determined which line was more similar to the parent myeloma.

Development and standardization of a cytotoxic micro-assay for detection of enterotoxins: survey of enterotoxins from Escherichia coli of infant origin.

The development of a practical cytotoxic micro-assay for detection of enterotoxins in crude bacterial lysates of E. coli and other Gram-negative bacteria, is described. This quantitative assay is based on growth inhibition of mouse-fibroblasts, maintained in suspension or by inhibition of uptake of DNA precursors.

Bacteriocin typing by leakage of ultraviolet light-absorbing material.

A rapid and reproducible method of bacteriocin typing is described based on leakage of ultraviolet light-absorbing material (UVAM), detectable in supernatants of bacteriocin-sensitive cultures, by means of a spectrophotometer. The prerequisites for reproducible results, with nonsignificant fluctuations in standard error of the mean, are: a set of standardized bacteriocins, produced under defined conditions and of determined strength. These must interact with the unknown bacterial culture in suspension and at a given ratio in order to achieve an optimal multiplicity of interaction.

Bacterial proteinaceous products (bacteriocins) as cytotoxic agents of neoplasia.

Several bacteriocins, bacterial proteinaceous antibiotics, are shown to markedly inhibit the division of various established (neoplastic) mammalian cell lines. The bacteriocins tested originated from Escherichia coli, Pseudomonas aeruginosa, Vibrio cholerae, and Vibrio eltor. Using exponentially growing L60T mouse fibroblasts, the inhibitory effect was concentration dependent, and a growth inhibitory unit, equivalent to cytotoxic index 50, was established.

Mode of Action of Vibriocin: Initial Interaction with Vibrio comma Cells.

Certain metabolic requirements, upon initial interaction of sensitive cells with vibriocin, were a prerequisite for lethal activity. Transient "immunity" of these cells, manifested under suboptimal growth conditions, differed from the immunity of vibriocinogenic cells.

Induction and immunity in vibriocinogenic bacteria.

Vibriocinogenic bacteria were found to differ in sensitivity to mitomycin C from the corresponding indicator strain, and immunity to vibriocin disappeared with post-inductional growth.