cGMP production of astatine-211-labeled anti-CD45 antibodies for use in allogeneic hematopoietic cell transplantation for treatment of advanced hematopoietic malignancies.

The objective of this study was to translate reaction conditions and quality control methods used for production of an astatine-211(211At)-labeled anti-CD45 monoclonal antibody (MAb) conjugate, 211At-BC8-B10, from the laboratory setting to cGMP production. Five separate materials were produced in the preparation of 211At-BC8-B10: (1) p-isothiocyanato-phenethyl-closo-decaborate(2-) (B10-NCS), (2) anti-CD45 MAb, BC8, (3) BC8-B10 MAb conjugate, (4) [211At]NaAt, and (5) 211At-BC8-B10. The 211At-labeling reagent, B10-NCS, was synthesized as previously reported.

Flow cytometric-membrane potential detection of sodium channel active marine toxins: application to ciguatoxins in fish muscle and feasibility of automating saxitoxin detection.

Ciguatoxins are potent neurotoxins with a significant public health impact. Cytotoxicity assays have allowed the most sensitive means of detection of ciguatoxin-like activity without reliance on mouse bioassays and have been invaluable in studying outbreaks. An improvement of these cell-based assays is presented here in which rapid flow cytometric detection of ciguatoxins and saxitoxins is demonstrated using fluorescent voltage sensitive dyes.

Transient removal of CD46 is safe and increases B-cell depletion by rituximab in CD46 transgenic mice and macaques.

We have developed a technology that depletes the complement regulatory protein (CRP) CD46 from the cell surface, and thereby sensitizes tumor cells to complement-dependent cytotoxicity triggered by therapeutic monoclonal antibodies (mAbs). This technology is based on a small recombinant protein, Ad35K++, which induces the internalization and subsequent degradation of CD46. In preliminary studies, we had demonstrated the utility of the combination of Ad35K++ and several commercially available mAbs such as rituximab, alemtuzumab, and trastuzumab in enhancing cell killing in vitro as well as in vivo in murine xenograft and syngeneic tumor models.

Notch-mediated expansion of human cord blood progenitor cells capable of rapid myeloid reconstitution.

Delayed myeloid engraftment after cord blood transplantation (CBT) is thought to result from inadequate numbers of progenitor cells in the graft and is associated with increased early transplant-related morbidity and mortality. New culture strategies that increase the number of cord blood progenitors capable of rapid myeloid engraftment after CBT would allow more widespread use of this stem cell source for transplantation. Here we report the development of a clinically relevant Notch-mediated ex vivo expansion system for human CD34(+) cord blood progenitors that results in a marked increase in the absolute number of stem/progenitor cells, including those capable of enhanced repopulation in the marrow of immunodeficient nonobese diabetic-severe combined immunodeficient (NOD-SCID) mice.

Flow cytometric detection of saxitoxins using fluorescent voltage-sensitive dyes.

By virtue of their ability to block depolarization of nerve cells, the saxitoxins exert the toxic effects associated with paralytic shellfish poisoning and allow for their detection through various methodologies. When veratridine-induced depolarization is followed using voltage-sensitive fluorescent dyes, the presence of these toxic blocking agents can be observed as a decrease in fluorescence of dye-treated nerve cells. Detection using flow cytometry provides for selection of the most responsive population of cultured mouse neuroblastoma (Neuro 2a) cells thereby enhancing assay sensitivity and this approach can be accomplished in real time.

Detection of paralytic shellfish poison by rapid cell bioassay: antagonism of voltage-gated sodium channel active toxins in vitro.

Although cytotoxicity assays provide several advantages over mouse bioassays, sodium channel-blocking marine toxins, such as those associated with paralytic shellfish poison (PSP), require prolonged incubation periods of 24-48 h. This is in marked contrast to in vitro detection of sodium channel-enhancing marine toxins such as ciguatoxins or brevetoxins which can be accomplished in as few as 4-6 h. We developed a modified PSP cell bioassay that is as rapid as in vitro methods for sodium channel-enhancing toxins.

A pilot study for the detection of acute ciguatera intoxication in human blood.

Introduction: Ciguatera fish poisoning arises from consumption of any of the 400 species of tropical marine reef fish containing polyether toxins. No laboratory method is available for clinical diagnosis of acute ciguatera poisoning. The objective of this pilot study was to ascertain the potential usefulness of a bioassay to detect ciguatoxins in humans suspected of acute intoxication.