BACKGROUND: Allogeneic natural killer (NK) cells are known to show medium to high cytotoxic activity against HLA-nonidentical leukemia or tumor cells. For a possible benefit of post transplant treatment with NK cells after haploidentical stem cell transplantation (haplo-SCT) we developed a clinical scale procedure for NK cell processing observing Good Manufacturing Practice (GMP). METHODS: Allogeneic donor NK cells were selected from 15 unstimulated leukaphereses using two rounds of immunomagnetic T cell depletion, followed by an NK cell enrichment step. CD56 (+)CD3 (-) NK cells were stimulated and expanded in vitro according to GMP. Quality control of NK cell purity, residual T cells and cytotoxic activity was done by multi-coloured flow cytometric analyses. RESULTS: Purification led to an absolute number of 234-1 237 x 10 (6) CD56 (+)CD3 (-) NK cells from leukapheresis harvests with a median purity of 95 % and a 4 to 6(1/2) log depletion of T cells. After two weeks stimulation with IL-2 a five-fold expansion of NK cells with a T cell contamination below 0.1 % was reached. Median cell viability was 95 % after purification and 99 % after expansion. The IL-2 stimulated NK cells showed a highly increased lytic activity against the MHC-I deficient K562 cells compared to freshly isolated NK cells and a medium cytotoxicity against patients' leukemic cells. CONCLUSIONS: Clinical scale enrichment and activation of allogeneic donor NK cells is feasible. High dose NK cell application may be a new treatment option for pediatric patients with leukemia or solid tumors in case of minimal residual disease or unbalanced chimerism post haplo-SCT as we could show for the first three patients .

Antigens, CD19↗

PubMedDate not supplied

Signal perception and intracellular signal transduction in plant pathogen defense.

Disease resistance in plant/pathogen interactions requires sensitive and specific recognition mechanisms for pathogen-derived signals in plants. Cultured parsley (Petroselinum crispum) cells respond to treatment with a crude cell wall preparation derived from the phytopathogenic fungus Phytophthora sojae with transcriptional activation of the same set of defense-related genes as are activated in parsley leaves upon infection with fungal spores. A 13 amino acid core sequence (Pep-13) of a 42 kDa fungal cell wall glycoprotein was identified, which stimulates the same responses as the crude cell wall elicitor, namely macroscopic Ca2+ and H(+)-influxes, effluxes of K(+)- and Cl- ions, production of active oxygen species (oxidative burst), defense-related gene activation, and formation of antifungal phytoalexins. Using [125I]Tyr-Pep-13 as ligand in binding assays, a single-class high-affinity binding site in parsley microsomal membranes and protoplasts could be detected. Binding was specific, saturable, and reversible. By chemical crosslinking, a 91 kDa parsley plasma membrane protein was identified to be the receptor of the peptide elicitor. Isolation of this receptor protein involved in pathogen defense in plants is under way.

Anti-Infective Agents↗

PubMedDate not supplied

Human infections with Shiga toxin-producing Escherichia coli other than serogroup O157 in Germany.

We investigated different types of Shiga toxin-producing Escherichia coli (STEC) not belonging to serogroup O157 for their role as human pathogens. Non-O157 STEC isolated from 89 human patients in Germany were characterized according to serotypes, virulence markers, and association with human illness. EaeA-positive STEC were isolated from 54 (60.7%) of the patients and were frequently associated with severe diarrheal disease, hemolytic uremic syndrome, and young age. EaeA-negative STEC were found in 35 (39.3%) of the patients and were more associated with clinically uncomplicated cases and adult patients. For pediatric patients, a serotype-independent diagnosis of STEC is recommended.

Adhesins, Bacterial↗

PubMedDate not supplied

[On the size of the kidney in the radiologic picture].

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Female↗