Good manufacturing practice production of CD34+ progenitor-derived NK cells for adoptive immunotherapy in acute myeloid leukemia.

Allogeneic natural killer (NK) cell-based immunotherapy is a promising, well-tolerated adjuvant therapeutic approach for acute myeloid leukemia (AML). For reproducible NK cell immunotherapy, a homogenous, pure and scalable NK cell product is preferred. Therefore, we developed a good manufacturing practice (GMP)-compliant, cytokine-based ex vivo manufacturing process for generating NK cells from CD34+ hematopoietic stem and progenitor cells (HSPC). This manufacturing process combines amongst others IL15 and IL12 and the aryl hydrocarbon receptor antagonist StemRegenin-1 (SR1) to generate a consistent and active NK cell product that fits the requirements for NK cell immunotherapy well. The cell culture protocol was first optimized to generate NK cells with required expansion and differentiation capacity in GMP-compliant closed system cell culture bags. In addition, phenotype, antitumor potency, proliferative and metabolic capacity were evaluated to characterize the HSPC-NK product. Subsequently, seven batches were manufactured for qualification of the process. All seven runs demonstrated consistent results for proliferation, differentiation and antitumor potency, and preliminary specifications for the investigational medicinal product for early clinical phase trials were set. This GMP-compliant manufacturing process for HSPC-NK cells (named RNK001 cells) is used to produce NK cell batches applied in the clinical trial 'Infusion of ex vivo-generated allogeneic natural killer cells in combination with subcutaneous IL2 in patients with acute myeloid leukemia' approved by the Dutch Ethics Committee (EudraCT 2019-001929-27).

Structural and molecular studies of human chorionic gonadotropin and its receptor.

Human chorionic gonadotropin (hCG) is a placental hormone that stimulates secretion of the pregnancy-sustaining steroid progesterone. It and other glycoprotein hormones are disulfide-rich heterodimers that share a common alpha chain and distinctive beta chains specific to their particular G protein-linked receptors. We determined the structure of partially deglycosylated hCG at 2.6 A resolution from multiwavelength anomalous diffraction (MAD) measurements of a selenomethionyl hCG crystal. We have also begun three- and four-dimensional structural studies on the biologically active hormone and have determined the structure of the carbohydrate attached to the alpha-subunit. Despite little sequence similarity limited to 10% identity, the alpha and beta subunits of hCG maintain strikingly similar tertiary folds, with cystine-knot motifs at cores of extended hairpin loops. Structural and sequence comparisons indicate an evolutionary homology between the glycoprotein hormone chains and other cystine-knot proteins, notably PDGF, TGF-beta, and NGF. This structural similarity has led us to speculate that early hCG secretion has a broader role than solely the stimulation of the corpus luteum; indeed, levels of hCG, which rise rapidly in the circulation after implantation, are greater than the levels necessary for corpus luteum function. One such role of hCG or its subunits could be as a growth factor that facilitates endometrial receptivity. Our studies of hCG have also identified structural variants, notably in the carbohydrate moiety, that are distinctive for patients with a variety of disorders of pregnancy, including hydatidiform mole and choriocarcinoma. We have also focused our efforts on using information gleaned from the structure of hCG for the design of drug-like molecules that might serve as either agonists or antagonists of hCG. To facilitate these experiments, we have designed a rapid screen for the identification of molecules that might bind the hCG receptor by identifying compounds that disrupt binding of hCG to its receptor. This screen employs a filamentous phage that displays the extracellular domain of the hCG receptor on its surface. Thus far, we have identified a few compounds that disrupt binding of hCG with its receptor at a concentration of approximately 1 micromolar. These "lead" molecules are currently being modified in an attempt to identify a molecule that can disrupt binding of hCG at nanomolar concentrations.

Carbohydrate and peptide structure of the alpha- and beta-subunits of human chorionic gonadotropin from normal and aberrant pregnancy and choriocarcinoma.

Human chorionic gonadotropin (hCG), purified from the urine of 14 individuals with normal pregnancy, diabetic pregnancy, hydatidiform mole, or choriocarcinoma, plus two hCG standard preparations, was examined for concurrent peptide-sequence and asparagine (N)- and serine (O)-linked carbohydrate heterogeneity. Protein-sequence analysis was used to measure amino-terminal heterogeneity and the "nicking" of internal peptide bonds. The use of high-pH anion-exchange chromatography coupled with the increased sensitivity of pulsed amperometric detection (HPAE/PAD) revealed that distinct proportions of both hCG alpha- and beta-subunits from normal and aberrant pregnancy are hyperglycosylated, and that it is the extent of the specific subunit hyperglycosylation that significantly increases in malignant disease. Peptide-bond nicking was restricted to a single linkage (beta 47-48) in normal and diabetic pregnancy, but occurred at two sites in standard preparations, at three sites in hydatidiform mole, and at three sites in choriocarcinoma beta-subunit. In the carbohydrate moiety, alpha-subunit from normal pregnancy hCG contained nonfucosylated, mono- and biantennary N-linked structures (49.3 and 36.7%, means); fucosylated biantennary and triantennary oligosaccharides were also identified (7.3 and 6.9%). In choriocarcinoma alpha-subunit, the level of fucosylated biantennary increased, offset by a parallel decrease in the predominant biantennary structure of normal pregnancy (P < 0.0001). The beta-subunit from normal pregnancy hCG contained fucosylated and nonfucosylated biantennary N-linked structures; however, mono- and triantennary oligosaccharides were also identified (4.6 and 13.7%). For O-linked glycans, in beta-subunit from normal pregnancy, disaccharide-core structure predominated, whereas tetrasaccharide-core structure was also detected (15.6%). A trend was demonstrated in beta-subunit: the proportions of the nonpredominating N- and O-linked oligosaccharides increased stepwise from normal pregnancy to hydatidiform mole to choriocarcinoma. The increases were: for monoantennary oligosaccharide, 4.6 to 6.8 to 11.2%; for triantennary, 13.7 to 26.7 to 51.5% and, for O-linked tetrasaccharide-core structure, 15.6 to 23.0 to 74.8%. For hCG from individual diabetic pregnancy, the principal N-linked structure (34.7%) was consistent with a biantennary oligosaccharide previously reported only in carcinoma; and sialylation of both N- and O-linked antennae was significantly decreased compared to that of normal pregnancy. Taken collectively, the distinctive patterns of subunit-specific, predominant oligosaccharides appear to reflect the steric effect of local protein structure during glycosylation processes. The evidence of alternative or "hyperbranched" glycoforms on both alpha- and beta-subunits, seen at low levels in normal pregnancy and at increased or even predominant levels in malignant disease, suggests alternative substrate accessibility for Golgi processing enzymes, alpha 1,6 fucosyltransferase and N-acetylglucosaminyltransferase IV, in distinct proportions of subunit molecules.

The heterogeneity of human chorionic gonadotropin (hCG). I. Characterization of peptide heterogeneity in 13 individual preparations of hCG.

Peptide variations in the alpha-subunit (molecules starting at alpha 3 and alpha 4) and beta-subunit (missing linkages at beta 44-45 and beta 47-48) of hCG have been reported by several investigators. Studies, however, have been limited to standard hCG preparations (purified from large pools of urine) and other hCG samples from mixed urines. In this study we used chromatographic procedures to purify the total hCG content of 13 individual urines, 6 from patients with pregnancy and 7 from those with trophoblast disease (no hCG-containing fractions were excluded). Then, we examined for the first time the peptide variability among individual samples of hCG. We report 1) that individual hCG preparations have nicks (missing linkages) in the beta-subunit, primarily between residue 47-48 (11 of 13 samples) and, less commonly, at the linkage 44-45 or 46-47 (3 of 13 samples); 2) the extent of nicking varies greatly between individual preparations (range, 0-100% of molecules); 3) varying alpha-subunit N-terminal heterogeneity (N-terminus starting at alpha 3 or alpha 4) was also present (range, 0-28% of molecules), but was confined to preparations from individuals with trophoblast disease (6 of 7 samples from trophoblast disease urine, 0 of 6 from pregnancy urine); 4) hCG missing the beta-subunit C-terminal region was also detected (2 of 13 hCG preparations); and 5) 1 of 13 preparations was nicked on the hCG alpha-subunit, between residues 70 and 71. Thus, 12 of 13 individual hCG samples demonstrated at least 1 of 4 different forms of peptide heterogeneity. We conclude that individual hCG samples vary widely in the type and extent of peptide heterogeneity, an observation that is not appreciated when pools of hCG are studied.

ATP-coupled transport of vesicular stomatitis virus G protein between the endoplasmic reticulum and the Golgi.

The temperature and ATP dependence of transport of the vesicular stomatitis virus strain ts045 G protein from the endoplasmic reticulum (ER) to an early Golgi compartment containing mannosidase I was studied in the mutant Chinese hamster ovary cell clone 15B. Appearance of G protein containing the Man5GlcNAc2 oligosaccharide species occurred after a shift to the permissive temperature with a lag period of 5 min and without detectable formation of the intermediate Man7GlcNAc2 and Man6GlcNAc2 species. Two biochemically distinct transport steps were detected during transport from the ER to the Golgi. An initial step is temperature sensitive, thermoreversible, and requires a high threshold of cellular ATP for maximal rate of transport (80% of the normal cellular ATP pool). Export from the ER is inhibited at 65% of the normal cellular ATP pool. Prolonged incubation at reduced levels of cellular ATP or at the restrictive temperature resulted in the accumulation of G protein in either the Man8GlcNAc2 species or the Man7GlcNAc2 and Man6GlcNAc2 species, respectively. Reversal of the temperature-sensitive block is ATP coupled. A second step is insensitive to incubation at the restrictive temperature and proceeds efficiently when the cellular ATP pool is reduced to 20% of the control. G protein accumulates at this intermediate step during prolonged incubation at 15 degrees C. The data suggest a functional division of processes required for transport of protein between the ER and Golgi compartments. The two steps may reflect the export (budding) and delivery (fusion) of proteins through vesicular trafficking between the ER and Golgi.