Feedback regulation of antibody formation by suppressive B cell factor: preferential suppression of high-affinity antibody production by memory B lymphocytes

Cloned TS4.44 cells, which were hybridized HAT-sensitive 3T3-4E cells with B cells stimulated by immune complexes produce a lymphokine, biochemical and biological characteristics of which are identical with those of conventional suppressive B cell factor (SBF) synthesized by Fc receptor bearing B cells stimulated with immune complexes. This factor is known to suppress B cell responses to antigen/mitogen. The present studies were carried out by using this hybridoma-derived SBF to characterize the large proportion of B cells sensitive to SBF and the small proportion of B cells resistant to it in terms of affinities of antibodies which these cells are able to produce. The treatment of normal spleen cells with SBF resulted in a 50-70% decrease in anti-dinitrophenyl (DNP) antibody production when the cells were transferred into X-ray-irradiated mice along with alum-precipitated dinitrophenyl-conjugated keyhole limpet hemocyanin (DNP-KLH). The affinity of anti-DNP antibody molecules produced in these mice was significantly lower than that of the controls, even if immunization was repeated. The target cells for SBF were B, and not helper T cells which might be involved in the process of affinity maturation. A single treatment of spleen cells in vitro with SBF was sufficient to abrogate the precursors committed to mediate high-affinity anti-DNP antibody responses, since the retreatment with SBF in vitro and transfer into the second irradiated recipients along with antigens of spleen cells of mice to which SBF-treated spleen cells were transferred 3 weeks before resulted in almost the same level of plaque-forming-cell-responses as in mice which received medium-treated.(ABSTRACT TRUNCATED AT 250 WORDS)

Two high-performance liquid chromatographic methods for quantitation of theophylline in plasma

Two high-performance liquid chromatographic methods are described for the assay of theophylline in plasma. Both allowed the separation of theophylline from the caffeine metabolites, theobromine and 1,7-dimethylxanthine. Method A, using 8-chlorotheophylline as internal standard, involved back extraction of theophylline from organic extract with 0.1 M sodium hydroxide. Method B used generally accepted solvent extraction followed by evaporation and beta-hydroxyethyltheophylline as internal standard. High-performance liquid chromatographic analyses were performed on reversed-phase phenyl columns (25 X 0.46 and 25 X 0.41 cm) using 20% methanol in 20 mM phosphate buffer at pH 5.6 for Method A and 2% acetonitrile and 8% methanol in 20 mM phosphate buffer for Method B. The column effluent was monitored at UV 273 nm. Standard curves for both Methods A and B were fitted by linear regression (r greater than 0.999) in the concentration range of 0.05-50 micrograms/ml. Either method was selective, accurate and reproducible over the concentration range 0.08-26 micrograms/ml. However, compared with Method B, Method A provided significant advantages in terms of simplicity, speed and efficiency.

A novel lymphokine derived from human IgG Fc receptor-bearing B cells: its suppressive effect on activated T and B lymphocytes including tumour cells in vitro

Peripheral blood FcR gamma-bearing human B cells, but neither T cells nor adherent cells, produce an immunoregulatory lymphokine after receiving the stimulation of FcR gamma by immune complexes--antibody-sensitized erythrocytes (EA). This factor suppresses polyclonal immunoglobulin (Ig) production of B cells to pokeweed mitogen (PWM) and Nocardia opaca delipidated cell mitogen (NDCM), indicating that not only B cells, but also T cells are targets for this factor. It also inhibits the proliferation of mitogen-activated mononuclear and T and B tumour cells in vitro. The inhibitory effect on tumour cell growth is cytostatic, but not cytotoxic as in the case of lymphotoxin (LT). All these suppressive effects are observed in a HLA-non-restricted manner. Irradiation (2000 rads) of FcR gamma + B cells does not inhibit the production of this suppressive factor, implying that DNA synthesis is unnecessary. Nonstimulated FcR gamma + B cells retain the precursor activity for Ig-forming cells, since mononuclear cells untreated with EA respond to the mitogens, resulting in Ig production. However, it is worthy to note that they lose the activity when stimulated with immune complexes. Thus, the property obtained from human FcR gamma + B cells is similar to, but distinct from, a murine suppressive B-cell factor (SBF) prepared by the same procedure as for the human factor. Nevertheless, the observation in the present studies on the human analogue to murine SBF suggests that this factor, tentatively termed human SBF, appears to be a novel lymphokine which is different from any other factors, including LT, and that FcR-bearing B cells play an important role in the immunoregulatory mechanism in humans, as in the case of mice.

Migration and differentiation of bone marrow lymphocytes: development of surface immunoglobulin, Fc receptor, complement receptor, and functional responsiveness as studied with anti-allotype serum

Immunofluorescent studies using fluorescein isothiocyanate-conjugated mouse anti-allotype antibody were carried out to study the migration pattern and the development of surface Ig (SIg), Fc receptor for IgG (FcR gamma), and complement receptor (CR) or mouse bone marrow lymphocytes following intravenous injection into congenic mice. After transfer of bone marrow cells from CSW mice into untreated congenic CWB mice, the absolute number of donor-type SIg-bearing (SIg+) cells and the proportion of either FcR gamma- or CR-bearing (FcR gamma+ or CR+) cells in donor-type SIg+ cells were evaluated in the recipient spleen and the results were compared with those obtained after the transfer of CSW spleen cells. After injection of donor bone marrow cells, detectable donor-type SIg+ cells, although few initially, increased from day 1 to Day 2 and reached a plateau thereafter. The proportion of FcR gamma+ cells in donor-type SIg+ cells, although very low in the donor marrow inoculum, increased progressively after 1 day to reach a maximum at Day 5 (90%). On the other hand, following the transfer of spleen cells, the proportion of FcR gamma+ cells remained at high levels (90%) for 5 days after transfer. Likewise, the proportion of CR+ cells in donor-type SIg+ cells was very low (less than 1%) in the original donor bone marrow cells but high (60%) in the donor spleen cells. However, in transferring bone marrow cells this proportion also increased in the recipient spleen to reach a maximum (49%) at Day 5 although it was lower compared to the percentage of FcR gamma+ cells in donor SIg+ cells. Furthermore, the ability of functional responsiveness to antigen was also examined in the same system by detecting plaque-forming cells (PFC) from donor origin. In transferring donor bone marrow cells into recipient, the participation of donor cells in the PFC response was very low when the recipients were primed with sheep red blood cells at Day 3 after transfer. However, when the recipients were primed at Days 7 to 21 after transfer, increasing numbers of the donor marrow-derived cells were involved in the PFC response. Thus, the present study demonstrates that the bone marrow-derived lymphocytes, albeit lacking both distinctive surface receptors (IgM, FcR gamma, CR) and the functional responsiveness to antigen, continue their development along the B-cell lineage after migrating into the spleen, as evidenced by the surface receptor expression and participation in the antibody response.

Dissolution of human cholesterol gallstones in stimulated chenodeoxycholate-rich and ursodeoxycholate-rich biles. An in vitro study of dissolution rates and mechanisms

We have compared the kinetics and physical-chemical mechanisms of human cholesterol gallstone dissolution in simulated normal, chenodeoxycholate-rich, and ursodeoxycholate-rich " biles ." Owing to reduced micellar cholesterol solubilizing capacities, dissolution rates in ursodeoxycholate-rich biles were initially slower than in normal or chenodeoxycholate-rich biles . At later time points, dissolution rates in ursodeoxycholate-rich bile became accelerated; this was shown to be associated with the development of a lamellar liquid-crystalline phase that took place first on the stones' surfaces and was then followed by dispersion of liquid-crystalline vesicles into the micellar solution. As subsequent dissolution occurred in a two-phase system of micelles and liquid-crystalline vesicles, the quantity of cholesterol solubilized exceeded micellar saturation. In normal and chenodeoxycholate-rich biles , no phase changes were observed either on the surfaces of the stones or in the micellar solution, and the quantity of cholesterol solubilized was limited by micellar saturation. These results was limited by micellar saturation. These results are consistent with phase equilibria diagrams of the simulated bile systems and suggest that the predominant physical-chemical mechanism of in vivo gallstone dissolution with ursodeoxycholic acid is via liquid crystalline dispersion of cholesterol. In contrast, micellar dissolution of cholesterol is the only mechanism possible with chenodeoxycholic acid.

Immunological characterization of FcR gamma bearing and nonbearing B cells: functional modulation of immune complexes

By the 1g sedimentation method using discontinuous gradients of Ficoll solution (concentrations of 6 to 14%), keyhole limpet hemocyanin (KLH)-primed spleen cells of C3H/He or DBA/2 mice were fractionated into 4 to 10 populations after IgG antibody-coated erythrocytes (EA gamma) rosetting and then treatment with anti-Thy-1.2 + complement (C). No significant difference was observed in the distribution of isotype specificities of surface immunoglobulins on B cells in each population thus fractionated, when determined by indirect immunofluorescence staining. The mixture of the 12 and 14% Ficoll fractions contained 95% of B cells bearing Fc receptor for IgG (FcR+ gamma) and 3.58% of antigen-binding cells (ABC) for KLH, while the 8% Ficoll fraction included 15% of FcR+ gamma B cells and 1.53% of ABC. Nevertheless, the FcR- gamma B-cell-enriched populations caused intensive plaque-forming cell (PFC) responses to dinitrophenol (DNP), whereas FcR+ gamma B-cell-enriched populations generated weak responses. Noteworthy is that 4 days preculture of a population containing 95% FcR+ gamma B cells resulted in the appearance of precursor activity which was ascertained by a further 4 days culture of these cells with antigen, DNP-dextran. These findings suggest that FcR gamma bearing B cells intrinsically possess precursor activity for IgM/IgG antibody-forming cells, but lose it transiently by binding immune complexes (IC). Moreover, the titer of a factor suppressing anti-DNP PFC responses (suppressive B-cell factor, SBF) was higher in the 24-hr culture supernatants of the FcR+ gamma B-cell-enriched fraction than of the FcR- gamma B-cell-enriched fraction, suggesting that SBF is produced by FcR+ gamma B cells themselves. Thus, IC seems to play an important role for the negative feedback regulation of antibody production by stimulating FcR gamma bearing B cells.

Quantitative determination of dextromethorphan and three metabolites in urine by reverse-phase high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method for the quantitation of dextromethorphan (I) and its three metabolites, dextrorphan (II), 3-hydroxy-9 alpha,13 alpha,14 alpha-morphinan (III), and 3-methoxy-9 alpha,13 alpha,14 alpha-morphinan (IV), in urine was developed. For the analysis of nonconjugated compounds, urine samples at pH 11-11.5, containing 3-methoxy-17-methyl-10-oxo-9 alpha,13 alpha,14 alpha-morphinan as an internal standard, were applied to an extraction column, and the compounds were eluted with 10% n-butyl alcohol-hexane. The organic eluant was extracted with 0.1 M HCl, and an aliquot of the acidic extract was analyzed by HPLC utilizing a 5-micron phenyl column (25 X 0.46-cm i.d.) with a mobile phase of 10 mM potassium phosphate-acetonitrile (45:55, pH 4.0); the column effluent was monitored by UV detection at 280 nm. Free and conjugated metabolites in the enzyme-treated urine were analyzed by selective extraction of I and IV with hexane from urine samples at pH greater than 12 and extraction of II and III with 10% n-butyl alcohol-hexane from urine samples at pH 11-11.5. The minimum quantifiable levels of I-IV ranged from 0.017 to 0.09 micrograms of base/mL and from 0.11 to 0.21 micrograms of base/mL in nonhydrolyzed and hydrolyzed urine, respectively.

Migration of bone marrow lymphocytes in mice: immunofluorescent staining using antiallotype serum

Bone marrow cells from CSW (Igha) mice were injected intravenously into the congeneic CWB (Ighb) mice. The lymphoid tissues of the recipient CWB mice were examined for donor type surface immunoglobulin (SIg)-positive cells using fluorescein isothiocyanate-conjugated antiallotype serum Ighb anti-Igha. Donor type SIg-positive cells were rarely found in the recipients immediately after injection. However, the donor type B cells increased in the recipient's spleen from days 1-2 and reached a plateau thereafter. The present method provides a useful means for studying the migration patterns and differentiation of bone marrow lymphocytes.

The "mirroring" of gallstones: description of a novel silvering method to determine the surface area of an irregular object. In vitro demonstration that multiple gallstones from the same gallbladder dissolve in unsaturated "bile" at the same rate

We describe a novel "silvering" method to determine the surface area of nonspherical objects and have applied this method to human cholesterol gallstones. A standard curve is first constructed, using data obtained from the dissolution rates of silver-coated plastic spheres of known dimensions in unstirred thiosulfate-ferricyanide solutions. Silver dissolution rates of silver-coated gallstones are then correlated with the standard curve so that the equivalent spherical surface area of the gallstones may be estimated. The technique has been applied to cholesterol dissolution rates of gallstones from the same patient and from different patients in unstirred bile salt (sodium chenodeoxycholate) solutions. The results demonstrate that cholesterol dissolution rates per unit surface area are identical for small stones as well as large ones, are identical for all stones from the same gallbladder, but are somewhat dissimilar for those originating from different gallbladders. The experimental results are in agreement with a priori theoretical predictions of mass transfer from spherical objects, and correlate satisfactorily with experimental dissolution rates of pure cholesterol monohydrate disks in unstirred bile salt solutions.

Distinct galactose phosphoenolpyruvate-dependent phosphotransferase system in Streptococcus lactis

Lactose-negative (Lac-) mutants were isolated from a variant of Streptococcus lactis C2 in which the lactose plasmid had become integrated into the chromosome. These mutants retained their parental growth characteristics on galactose (Lac- Gal+). This is in contrast to the Lac- variants obtained when the lactose plasmid is lost from S. lactis, which results in a slower growth rate on galactose (Lac- Gal+). The Lac- Gal+ mutants were defective in [14C]thiomethyl-beta-D-galactopyranoside accumulation, suggesting a defect in the lactose phosphoenolpyruvate-dependent phosphotransferase system, but still possessed the ability to form galactose-1-phosphate and galactose-6-phosphate from galactose in a ratio similar to that observed from the parental strain. The Lac- Gald variant formed only galactose-1-phosphate. The results imply that galactose is not translocated via the lactose phosphoenolpyruvate-dependent phosphotransferase system, but rather by a specific galactose phosphoenolpyruvate-dependent phosphotransferase system for which the genetic locus is also found on the lactose plasmid in S. lactis.

Antimicrobial agents from higher plants. Antimicrobial isoflavanoids and related substances from Glycyrrhiza glabra L. var. typica

Bioassay-directed fractionation of Glycyrrhiza glabra L. var. typica resulted in the isolation and characterization of glabridin (I), glabrol (2), glabrene (3), 3-hydroxyglabrol (4), 4'-O-methylglabridin (5), 3'-methoxyglabridin (6), formononetin (7), phaseollinisoflavan (8), hispaglabridin A (9), hispaglabridin B (13), salicylic acid and O-acetyl salicylic acid. Of these, hispaglabridin A, hispaglabridin B, 4'-O-methylglabridin, glabridin, glabrol and 3-hydroxyglabrol possess significant antimicrobial activity in vitro; hispaglabridin A, hispaglabridin B, 3'-methoxyglabridin, 4'-O-methylglabridin 3-hydroxyglabrol, phaseollinisoflavan, salicylic acid, and O, acetyl salicylic acid are newly found in Glycyrrhiza sp.; and hispaglabridin A, hispaglabridin B, 3'-methoxyglabridin, 4'-O-methylglabridin, and 3-hydroxyglabrol are new to the literature and their structures are proposed herein.

Antimicrobial agents from higher plants. An investigation of Hunnemannia fumariaefolia pseudoalcoholates of sanguinarine and chelerythrine

The antimicrobial activity seen in extracts of Hunnemmania fumariaefolia S. resides in the alkaloids. The activity seen in the non-polar fractions had been shown by chromatography, physicochemical measurements, and comparisons with authentic samples to be due to apparently artifactual formation of the pseudomethanolates and pseudoethanolates of the alkaloids sanguinarine and chelerythrine, which are abundant in the plant. The enhanced potency of the pseudoalcoholates of sanguinarine over the parent benzophenanthridine is discussed in comparison with the in vitro biopotencies of other analogs prepared for the purpose. It appears that the pseudoalcoholates may be useful prodrugs.

Solitary metastatic carcinoma of the spleen

A care is reported in which an isolated metastatic lesion of the spleen was discovered one year after a modified radical mastectomy for carcinoma of the breast, and seven years following total hysterectomy and bilateral salpingo-oophorectomy for carcinoma of the left ovary. Splenectomy was followed by significant clinical improvement of the patient who remains alive and well four years after operation. Regular physical and roentgen examinations have revealed no evidence of recurrent disease. The factors relating to the occurrence of solitary splenic metastasis are discussed briefly. This case is apparently the fifth reported in the literature.