Human monoclonal antibodies that neutralize anthrax toxin by inhibiting heptamer assembly

A panel of human anti-anthrax protective antigen IgG1 monoclonal antibodies were evaluated to determine the mechanism of toxin neutralization. AVP-22G12, AVP-1C6 and AVP-21D9 bound to the protective antigen with picomolar affinities to distinct non-overlapping linear epitopes. Two of the antibodies neutralized the anthrax toxin by completely inhibiting the protective antigen oligomer assembly process in vitro

Human anti-anthrax protective antigen neutralizing monoclonal antibodies derived from donors vaccinated with anthrax vaccine adsorbed

BACKGROUND: Potent anthrax toxin neutralizing human monoclonal antibodies were generated from peripheral blood lymphocytes obtained from Anthrax Vaccine Adsorbed (AVA) immune donors. The anti-anthrax toxin human monoclonal antibodies were evaluated for neutralization of anthrax lethal toxin in vivo in the Fisher 344 rat bolus toxin challenge model. METHODS: Human peripheral blood lymphocytes from AVA immunized donors were engrafted into severe combined immunodeficient (SCID) mice. Vaccination with anthrax protective antigen and lethal factor produced a significant increase in antigen specific human IgG in the mouse serum. The antibody producing lymphocytes were immortalized by hybridoma formation. The genes encoding the protective antibodies were rescued and stable cell lines expressing full-length human immunoglobulin were established. The antibodies were characterized by; (1) surface plasmon resonance; (2) inhibition of toxin in an in vitro mouse macrophage cell line protection assay and (3) in vivo in a Fischer 344 bolus lethal toxin challenge model. RESULTS: The range of antibodies generated were diverse with evidence of extensive hyper mutation, and all were of very high affinity for PA83~1 × 10(-10-11)M. Moreover all the antibodies were potent inhibitors of anthrax lethal toxin in vitro. A single IV dose of AVP-21D9 or AVP-22G12 was found to confer full protection with as little as 0.5× (AVP-21D9) and 1× (AVP-22G12) molar equivalence relative to the anthrax toxin in the rat challenge prophylaxis model. CONCLUSION: Here we describe a powerful technology to capture the recall antibody response to AVA vaccination and provide detailed molecular characterization of the protective human monoclonal antibodies. AVP-21D9, AVP-22G12 and AVP-1C6 protect rats from anthrax lethal toxin at low dose. Aglycosylated versions of the most potent antibodies are also protective in vivo, suggesting that lethal toxin neutralization is not Fc effector mediated. The protective effect of AVP-21D9 persists for at least one week in rats. These potent fully human anti-PA toxin-neutralizing antibodies are attractive candidates for prophylaxis and/or treatment against Anthrax Class A bioterrorism toxins

Reading, metacognition, and motivation: A follow-up study of German students in Grades 7 and 8

This follow-up study to van Kraayenoord and Schneider (1999) examined the performance in reading, metacognition and motivation related to reading of students in Grades 7 and 8. Results showed significant correlations between all of the variables. A multivariate analysis of variance showed that good and poor readers differed in reading self-concept and metacognitive measures related to reading and memory. A stepwise regression analysis suggested that the metacognitive variables were the best predictors of reading. Furthermore, a comparison of the results of the previous study with those of the current investigation revealed that the findings were stable over time. Since the period between the two studies is the time during which students make important decisions related to enrolment in one of three distinct school-types in Germany, we examined the results of various groups of students: those in Gymnasium (high educational track), Realschule (middle educational track), and Hauptschule (low educational track). Students in the Gymnasium scored significantly better than students in the other two groups on almost all variables related to reading. A re-analysis of the data from our first investigation found that the results of the Gymnasium students in the second study could be predicted from their results obtained during elementary school

Immunization and treatment methods for anthrax

A highly efficient method for generating human antibodies using recall technology is provided. In one aspect, human antibodies which are specific to the anthrax toxin are provided. In one aspect, human peripheral blood cells that have been pre-exposed to anthrax toxin are used in the SCID mouse model. This method results in high human antibody titers which are primarily of the IgG isotype and which contain antibodies of high specificity and affinity to desired antigens. The antibodies generated by this method can be used therapeutically and prophylactically for preventing or treating mammals exposed to anthrax. Thus, in one embodiment, a prophylactic or therapeutic agent used to counter the effects of anthrax toxin, released as a mechanism of bioterrorism, is provided. In one embodiment, a formulation and method for preventing and/or treating anthrax infection comprising a binding agent that prevents the assembly of the PA63 heptamer is also provided. Methods for diagnosis and methods to determine anthrax contamination are also described

Antibodies against protective antigen and methods of use for passive immunization and treatment of anthrax

A highly efficient method for generating human antibodies using recall technology is provided. In one aspect, human antibodies which are specific to the anthrax toxin are provided. In one aspect, human peripheral blood cells that have been pre-exposed to anthrax toxin are used in the SCID mouse model. This method results in high human antibody titers which are primarily of the IgG isotype and which contain antibodies of high specificity and affinity to desired antigens. The antibodies generated by this method can be used therapeutically and prophylactically for preventing or treating mammals exposed to anthrax. Thus, in one embodiment, a prophylactic or therapeutic agent used to counter the effects of anthrax toxin, released as a mechanism of bioterrorism, is provided. In one embodiment, a formulation and method for preventing and/or treating anthrax infection comprising a binding agent that prevents the assembly of the PA63 heptamer is also provided. Methods for diagnosis and methods to determine anthrax contamination are also described