Engraftment of human peripheral blood lymphocytes in normal strains of mice

Transplantation of bone marrow from SCID mice into lethally irradiated normal mice can potentially endow the normal recipients with characteristics typical of the immune-deficient SCID mouse. In the present study, we investigated whether intraperitoneal grafting of human peripheral blood lymphocytes (PBLs), which has been documented in the SCID mouse, can also be achieved in irradiated BALB/c mice radioprotected with SCID bone marrow. Evaluation of different radiation protocols suggested that, considering the quality of engraftment and rate of survival, optimal results were obtained with split dose total body irradiation (TBI; 4 Gy followed 3 days later by 10 Gy). Monitoring of mouse T cells in peripheral blood indicated an inverse correlation between the presence of such cells and the engraftment of human CD45+ cells in the peritoneum. Also, engraftment of human PBLs in nude BALB/c mice, conditioned with the same radiation protocol, was significantly higher than that achieved in their normal counterparts. Further improvement of human PBL engraftment was found when the mice were thymectomized 2 weeks before conditioning with split TBI. After transplantation of 80 x 10(6) human PBLs in such recipients, a marked engraftment of human T cells and B cells in the peritoneum cavity could be detected for at least 2 months, whereas significant amounts of human Ig could be detected for more than 3 months. Migration of human PBLs into internal organs such as spleen, liver, kidney, and lungs (and into thymus in nonthymectomized mice) was found within a few days of grafting and also persisted for 2 to 3 months. The majority of the engrafted lymphocytes were single-positive CD4+ and CD8+ T lymphocytes, about 50% of which were activated, as judged by their expression of HLA-DR. Staining with anti-CD25 antibody was lower compared with that found with anti-HLA-DR. CD20+ B cells were detected in all of the above-mentioned internal organs, but were mainly concentrated in the spleen. CD14+ monocytes could be detected only during the first week posttransplant of PBLs. Total human Ig in peripheral blood reached an average of 2.8 mg/mL 14 days posttransplant, and continued to be significant for several months. In vitro transformation by Epstein-Barr virus of human B cells from different tissues could be established 30 days after transplantation and led to outgrowth of two IgG+ cell lines, two IgM+ cell lines, and one IgA+ cell line producing 0.6 to 4.2 micrograms/mL human Ig in the supernatant.(ABSTRACT TRUNCATED AT 400 WORDS)

Treatment of neuroblastoma patients with antiganglioside GD2 antibody plus interleukin-2 induces antibody-dependent cellular cytotoxicity against neuroblastoma detected in vitro

Therapy of neuroblastoma patients with interleukin (IL)-2 activates effector cells capable of lysing tumor cells in vitro. When tumor cells are pretreated with certain monoclonal antibodies (MoAb), these in vivo activated effectors show augmented tumor lysis via antibody-dependent cellular cytotoxicity (ADCC). This study presents immunological analyses of serial blood samples from two refractory neuroblastoma patients who received combined in vivo therapy with murine anti-ganglioside GD2 monoclonal antibody 14.G2a and IL-2. These studies were designed to determine whether conditions that induce ADCC in vitro can be generated in vivo by combined therapy with IL-2 and MoAb. As shown previously, administration of IL-2 dramatically augments the ability of peripheral blood mononuclear cells (PBMC) to mediate ADCC. In addition, we demonstrate here that sera, obtained 1 h after infusion of 14.G2a, provides an effective source of functional antibody for ADCC mediated by PBMC from healthy donors. Finally, effective ADCC-mediated killing of neuroblastoma target cells was also achieved in vitro following IL-2 plus 14.G2a treatment when patients' effector cells were combined with patients' serum, as the source of 14.G2a antibody. These results indicate that this combination of IL-2 and 14.G2a generates conditions within the peripheral blood of pediatric neuroblastoma patients that enable their own lymphocytes to mediate antibody-dependent cellular cytotoxicity sufficient to effectively kill neuroblastoma cells in vitro.

In vitro inactivation of glucose-6-phosphate dehydrogenase from human red blood cells by acrolein: a possible biomarker of exposure

We have investigated the possibility of utilizing glucose-6-phosphate dehydrogenase (G6PD) as a macromolecular (biological) marker of acrolein exposure. The result showed a dose-dependent inactivation of the erythrocyte G6PD in situ or as a purified enzyme from human erythrocytes or yeast. Amino acid analysis on the chemically modified yeast G6PD showed a formation of a lysine adduct which is probably linked to the inactivation.

[Levels of insulin in serum during fasting and circadian blood pressure profile in young health men]

In order to investigate the relation of ambulatory blood pressure values to fasting plasma insulin, non-invasive 24-hour blood pressure monitoring was performed in 32 young normotensive males. Systolic and diastolic blood pressures were averaged for awake and asleep periods. Fasting plasma insulin levels correlated significantly with both asleep (r = 0.61; p < 0.001) and awake systolic blood pressures (r = 0.44; p < 0.02) but not with casual systolic blood pressure (r = 0.27). There were no significant associations of awake, asleep and causal diastolic blood pressures values with fasting plasma insulin levels (r = 0.15, 0.05 and 0.21, respectively). These results support the hypothesis that insulin may be a physiological determinant of blood pressure.

Plasma insulin and blood pressure response to oral glucose tolerance test in young borderline hypertensives

In order to evaluate whether borderline hypertension might be associated with hyperinsulinaemia, twenty non-obese borderline hypertensives and twenty matched normotensives underwent a standard oral glucose tolerance test and 24-h ambulatory blood pressure monitoring. Blood pressure, plasma glucose and insulin were measured at fasting and 15, 30, 60, 120 and 180 minutes after glucose load. Fasting plasma insulin was significantly higher in borderline hypertensives in comparison to normotensives (16.6 +/- 6.9 vs 12.4 +/- 4.2 mU/l; P < 0.05). Plasma insulin response estimated by the positive incremental area under the curve did not differ significantly between two groups but borderline hypertensives showed a larger interindividual difference. Decrease of systolic blood pressure after glucose load was significantly greater in borderline hypertensive subjects. Furthermore, blood pressure and plasma insulin relationship was different in borderline hypertensives compared to normotensives.

Translational options for the pir gene of plasmid R6K: multiple forms of the replication initiator protein pi

The autogenously controlled pir gene of plasmid R6K was believed to encode a single polypeptide that plays multiple roles in the plasmid's biology. We have isolated an opal (op) mutant at the 18th codon of the pir coding frame which does not totally abolish translation of pir mRNA. In extracts of cells containing this mutation two translational products (35 kDa and 30.2 kDa) have been detected. We propose that the 35-kDa polypeptide produced by the pir18 op mutation contains Trp substituted for Arg18 as the result of an opal readthrough. Translation, which results in the 30.2-kDa polypeptide, originates downstream from the UGA stop signal created by the mutation. Moreover, we realize now that the 30.2-kDa polypeptide is also produced in cells containing a wild-type (wt) pir gene. The shorter variant of the pi protein lacks replication initiation and inhibition functions, as well as autorepressor activity in vivo. We also show that an in-frame fusion of seven N-terminal codons of the trpE gene with a pir gene lacking the first two codons produces two polypeptides which replace the 35-kDa pi protein and are of similar molecular weight. Thus, at least three options exist in the translation of the wt pir mRNA. Start codons are most likely at codon positions 1, 6 or 7, and 36 or 38. Each of these five AUG codons is preceded by a consensus ribosome-binding site (RBS).

K(+)-evoked depolarization stimulates cyclic AMP accumulation in photoreceptor-enriched retinal cell cultures: role of calcium influx through dihydropyridine-sensitive calcium channels

The effect of membrane depolarization on cyclic AMP synthesis was studied in glia-free, low-density, monolayer cultures of chick retinal photoreceptors and neurons. In photoreceptor-enriched cultures prepared from embryonic day 6 retinas and cultured for 6 days, elevated K+ concentrations increased the intracellular concentration of cyclic AMP and stimulated the conversion of [3H]adenine to [3H]cyclic AMP. The K(+)-evoked increase of cyclic AMP accumulation was blocked by omitting CaCl2 from the incubation medium, indicating a requirement for extracellular Ca2+. Stimulation of cyclic AMP accumulation was also inhibited by nifedipine, methoxyverapamil, Cd2+, Co2+, and Mg2+, and was enhanced by the dihydropyridine Ca2+ channel agonist Bay K 8644. The enhancement of K(+)-evoked cyclic AMP accumulation by Bay K 8644 was antagonized by nifedipine. Thus, Ca2+ influx through dihydropyridine-sensitive channel is required for depolarization-evoked stimulation of cyclic AMP accumulation in photoreceptor-enriched cultures.

Relationship between fasting plasma insulin and ambulatory blood pressure in young, non-obese normotensive subjects

In order to investigate the relationship between ambulatory blood pressure values and fasting plasma insulin, non-invasive, 24-h blood pressure monitoring was performed in 32 young normotensive males. Systolic and diastolic blood pressures were averaged for awake and asleep periods. Fasting plasma insulin levels correlated significantly with both asleep (r = 0.61; P less than 0.001) and awake (r = 0.44; P less than 0.02) systolic blood pressure, but not with casual systolic blood pressure (r = 0.27). There were no significant associations between awake, asleep and casual diastolic blood pressure, and fasting plasma insulin levels (r = 0.15, 0.05 and 0.21, respectively). These results support the hypothesis that insulin may be a physiological determinant of blood pressure.

A unifying parameter to describe the clinical mechanics of hydrogel contact lenses

We studied the relation of postlens squeeze pressure to the clinical fit of hydrogel contact lenses. This relation was statistically significant (p less than 0.01) for a variety of contact lenses currently prescribed over a range of thickness, water content, back central optic radius, diameter, and back vertex power. The squeeze pressure provided a useful parameter to describe and compare the clinical fit of hydrogel contact lenses and a model with which the fit of a lens to an eye could be predicted. There was virtually no movement of the contact lenses across the eye when the squeeze pressure was more than -14 mm H2O (-1370 dynes/cm2). However, the mechanics of the lens motion when the squeeze pressure was less than this critical pressure appeared to be related to a more complicated combination of the squeeze pressure and the other forces in the eye-lens system.

Application of monoclonal antibodies for affinity electrophoresis

Monoclonal antibodies (MoAbs) to human alpha-fetoprotein (AFP) produced by 13 different murine hybridoma clones were used in affinity electrophoresis. The binding of MoAbs to AFP was studied in different experimental systems: crossed affinity immunoelectrophoresis, rocket affinity immunoelectrophoresis and zone affinity electrophoresis in agarose. Experimental data indicated that MoAb-AFP and AFP-MoAb-AFP complexes were formed during electrophoresis. Affinity electrophoresis seems to be a convenient and sensitive method for studies on the reaction of monoclonal antibodies with their antigens. In addition, the technique offers the possibility of calculating the dissociation constants of MoAb-AFP and of AFP-MoAb-AFP complexes and evaluating the reaction of MoAbs with different antigenic determinants.

Differential binding of soybean agglutinin to human neuroblastoma cell lines: potential application to autologous bone marrow transplantation

Normal human bone marrow cells were mixed with neuroblastoma cells from four different human cell lines, and the cell mixtures were separated by differential agglutination with soybean agglutinin (SBA). The unagglutinated cell fraction, previously shown to be highly enriched for the hematopoietic pluripotential stem cells and capable of reconstituting lethally irradiated adult patients with acute leukemia, was further fractionated by affinity chromatography on the lectin conjugated to Sepharose 6MB beads. Two independent assays, one using radiolabeling of the tumor cells and the other based on cloning of the neuroblastoma cells on agar, showed that the agglutination step alone removes 64-76% of the radiolabeled neuroblastoma cells and 85-98% of the clonogenic cells from the tumor/bone marrow cell mixture. Passage of the unagglutinated radiolabeled cells through SBA-Sepharose columns results in further purging of 28-53% of the neuroblastoma cells. Thus a combination of the two methods affords only one-log depletion for the neuroblastoma cells, compared to a three-log depletion achieved for a T-cell leukemia line CEM tested in parallel. It seems therefore that the agglutination technique, or the use of SBA-Sepharose columns, can be used only as a preliminary step for the purging of neuroblastoma cells from involved human bone marrow preparations. Staining with fluorescein isothiocyanate-conjugated SBA of nine different neuroblastoma cell lines, including the four tested in the fractionation studies, showed that more than 98% of the cells, of all the cell lines tested, specifically bind to the lectin, whereas no specific binding can be detected on the stem cell-enriched bone marrow cell fraction. However, the total number of receptors on the neuroblastoma cells is small compared to that of line CEM or normal granulocytes, which are strongly agglutinated by SBA. It seems therefore that the quantitative difference in the total number of SBA receptors is a crucial factor for purging by the agglutination technique or by affinity chromatography. Although these results show limitations to the use of both methods, this study establishes that all neuroblastoma cell lines tested express receptors for the lectin. Improved purging of neuroblastoma cells may possibly be achieved by targeting SBA-bound toxins or magnetic spheres to these receptors.

CT characteristics of sacral perineural cysts. Report of two cases

The authors report two cases in which the appearance of sacral perineural cysts, as seen in the computerized tomography scan, prompted the possible diagnosis of a neoplastic lesion. Additional investigation led to the proper diagnosis.