Production and molecular characterization of clinical phase i anti-melanoma mouse IgG3 monoclonal antibody R24.

R24 is a mouse IgG3 monoclonal antibody (mab) that reacts with the ganglioside GD3 expressed by cells of neuroectodermal origin. The anti-tumor activity of R24 has been demonstrated in initial phase I and pilot trials in patients suffering from metastatic melanoma. The purpose of this study was to investigate the biotechnological production and particularly the glycosylation of this clinically important antibody. Growth, metabolism, and IgG production of R24 secreting hybridoma cells were analyzed on 1 L bioreactor bench scale using repeated-batch mode. The amount of 57 mg of pure mab was obtained from 1.6 L crude supernatant by protein A chromatography. Western blot binding assays with sugar-specific lectins revealed glycosylation of the heavy chains, whereas no carbohydrates were detectable on the light chains. Because glycosylation is essential for antibody effector functions in vivo (such as complement fixation or binding to macrophage Fc receptors), mab R24 was subjected to both enzymatic deglycosylation using PNGase F and chemical deglycosylation by hydrazinolysis. Released glycans were structurally characterized by high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), matrix assisted laser desorption ionization time-of-flight (MALDI-TOF), and electrospray ionization quadrupole time-of-flight (ESI-QTOF) mass spectrometry. Six major biantennary chains of the complex glycosylation phenotype were found with variations in galactosylation and core fucosylation. The predominant N-linked structure, indicating the high degree of agalactosyl glycoforms, was the agalacto biantennary chain with a relative percentage of 57% (51% core-fucosylated, 6% nonfucosylated). The second most abundant oligosaccharide was the monogalacto biantennary chain amounting to 30% (26% core- and 4% nonfucosylated). The antibody contained 0.46 microg sialic acid per mg protein, which splits into 0.243 microg Neu5Gc and 0.217 microg Neu5Ac, corresponding to a Neu5Ac:Neu5Gc ratio of 1:1.06. Furthermore, the antigen specificity of R24 was determined by immunodetection of GD3 on thin-layer chromatograms, and real time GD3-antibody binding interactions were measured with an optical biosensor (BIAcore). From the structural data obtained in this study it is concluded that glycosylation of the antibody may be important in the clinical outcome of targeted anti-cancer immunotherapy.

DNA typing from skeletal remains: evaluation of multiplex and megaplex STR systems on DNA isolated from bone and teeth samples.

AIM: To evaluate the performance of three multiplex short tandem repeat (STR) systems (AmpflSTR Profiler, AmpflSTR Profiler Plus, and AmpflSTR COfiler), and a megaplex STR system (PowerPlex 16) on DNA extracted from the skeletal remains. By performing a microbial DNA challenge study, we also evaluated the influence of microbial DNA on human DNA typing. METHODS: A subset of 86 DNA extracts isolated from 8-50 years old bone and teeth samples, corresponding to 20 identification cases from mass graves in Croatia and Bosnia and Herzegovina, and to 4 paternity cases involving deceased parents in Spain, were analyzed by the above systems. RESULTS: Bone samples with no detectable human DNA (tested with Quantiblot), as well as teeth samples with detectable human DNA, were successfully amplified. Surprisingly, even in highly degraded samples, PowerPlex 16 offered very robust amplification for the both Penta E and Penta D markers. We observed a few non-specific extra peaks of 202 and 308 base pairs, which appeared to match 16S rRNA of the Pseudomonas halodenitrificans. CONCLUSION: AmpflSTR Profiler Kit, AmpflSTR Profiler Plus Kit, the AmpflSTR COfiler Kit, and the PowerPlex 16 system are very sensitive multiplex STR amplification systems, which can be successfully used to obtain a multilocus STR profile from old teeth and bone samples with minimal amounts (pg) of human DNA or even with no detectable human DNA.

Loss of calcineurin from the medial preoptic area of primiparous rats.

Western blot analyses reveal that calcineurin A (CNA), which is present in the hippocampus, basolateral amygdala, parietal cortex, and MPOA of virgin males and females, is undetectable only in the MPOA of primiparous females regardless of whether they had postpartum pup contact or not. In contrast, CNB was expressed at unchanging levels in the PC and MPOA. Similarly, G(alphao) and PKA(RI) were expressed at high levels in all of the brain regions of virgin males, virgin females, and primiparous females, supporting the concept that this loss of CNA is a specific event. Understanding how and why the expression of CNA, the sole neuronal Ca2+/CaM-dependent protein phosphatase, is down-regulated specifically in the MPOA of primiparous females may yield some insight into the signal transduction events that mediate the onset of mammalian maternal behavior.

Allele frequencies of six highly polymorphic DNA loci in the Croatian population.

The allele frequency distributions in a series of Croats were analyzed for six unlinked polymorphic DNA loci: THO1, FESFPS, VWA01, APOB, D1S80, and D17S5. The allele frequencies were determined for 100 unrelated genomic DNA samples. The observed heterozygote frequencies of the loci ranged from 0.63 to 0.76; however, the the expected heterozygosity ranged from 0.68 to 0.82, with only D17S5 having a significant excess of homozygous phenotypes (p < 0.001). The excess homozygosity seen in the D17S5 system may be due to allelic drop-out and warrants further technical analysis of that system, given the uniform lack of significant deviation in the other five systems. The forensic usefulness of these systems can be measured using two different statistics: the power of discrimination and the likelihood of a coincidental match. The power of discrimination ranged from 0.85 to 0.94 for the 6 systems with the combined likelihood of a coincidental match based on these 6 systems of 1 in 3.6 million, or slightly less than the population of Croatia. A second, more conservative estimator of the likelihood of a match is based on the most common phenotype for each system. If someone had the most common phenotype for each of the 6 systems, the chance of a coincidental match would be approximately 1 in 64,000. For paternity testing the usefulness of a system is measured by the average power of exclusion or (1-power of exclusion), the random man not excluded. The average power of exclusion, based on observed heterozygosity, ranged from 0.33 to 0.53, and the average power of exclusion based on the expected heterozygosity ranged from 0.39 to 0.64. The combined average power of exclusion was 99.2% for these 6 systems, using the expected heterozygosity. Based on the results of testing these six systems, there is no significant substructuring within the southern Croatian populations, and these systems provide a useful tool for forensic, paternity, and anthropological applications.

Genetic analysis of the glucose-6-phosphate dehydrogenase deficiency in a southern Croatia.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy. G6PD Mediterranean is caused by a C-->T transition at nucleotide 563, is characterized with less than 10% of normal enzyme activity and is classified as severe G6PD deficiency. Nineteen unrelated males from Southern Croatia with severe G6PD deficiency were tested, by enzyme digestion, for the presence of the Mediterranean mutation. Individuals with G6PD Mediterranean were further screened for the silent C-->T transition at nucleotide 1311. Four of the nineteen individuals were positive for the Mediterranean mutation (21%) and all four had the silent mutation.

Identification of war victims from mass graves in Croatia, Bosnia, and Herzegovina by use of standard forensic methods and DNA typing.

The postmortem remains of sixty-one war victims were excavated from 6 mass graves in Bosnia and Herzegovina one and a half years after interment Using standard identification methods, including the matching of medical and dental records, the recognition of distinguishing characteristics such as the use of clothing and belongings, and video superimposition, 35 persons were identified. For the remaining 26 persons identification efforts continue. DNA typing was performed at the HLA DQA1 locus and five PM system loci. Results from DNA typing were confirmed by other methods. DNA profiles of family members of 150 missing persons are now being developed using the 6 loci. These DNA profiles will then be compared with those generated from the bone and teeth remains of the unidentified victims.

Northern and southern Croatian population data on seven PCR-based loci.

Northern and southern Croatian sample populations were typed at seven PCR-based loci -LDLR, GYPA, HBGG, D7S8, Gc, HLA-DQA1 and D1S80. The results show that all loci meet Hardy-Weinberg expectations and that there is little evidence for association of alleles between loci. Allelic frequency distributions at all loci, except HLA-DQA1, show no differences between the northern and southern Croatian sample populations. Moreover, the population data for Croatians are similar to U.S. Caucasians; only HLA-DQA1 for southern Croatians was statistically different compared with U.S. Caucasians. A Croatian population database(s) has been created and can be used for forensic analyses to estimate the frequency of a multiple locus DNA profile.