Non-precipitating guinea-pig antibodies as products of limited recognition of antigenic sites on the ovalbumin molecule.

The non-precipitating guinea-pig IgG1 and IgG2 antibodies, produced by administration of an excessive dose of hen ovalbumin (OA), were capable of forming only certain soluble complexes having molar ratios of antibody to antigen lower than 1-5:1, which were lower than the minimum ratio of 2-5:1 shown by anti-OA antibodies precipitable with OA. This unusual property of the non-precipitating antibodies was caused by a limited number of antibody molecules capable of binding to one OA molecule simultaneously, since the maximum number of their Fab' fragments binding to one OA molecule was only three and markedly less than the number (7-8) of Fab' fragments of the precipitating IgG1 and IgG2 anti-OA antibodies binding to one OA molecule. These results demonstrate that the non-precipitating IgG1 and IgG2 anti-OA antibodies are those reacting with some particular antigenic sites on OA, a number of the antigenic sites too few to permit insoluble lattice formation.     

Abnormal expression of complement receptor (CR1) in IgA nephritis: increase in erythrocytes and loss on glomeruli in patients with impaired renal function

The number of complement receptor for C3b (CR1) molecules in erythrocytes from patients with renal diseases was measured by an immunoradiometric assay using monoclonal antibodies against CR1. IgA nephritis patients with high serum creatinine value (Scr) showed markedly elevated levels of CR1, whereas patients with normal Scr had normal CR1 levels. A similar increase in CR1 number was observed in membranoproliferative glomerular nephritis with high Scr. CR1 of these patients functioned normally as a cofactor of C3b inactivator in cleaving immune complex-bound C3b. In contrast, a high frequency (5/6) of negative staining of glomerular CR1 was observed in IgA nephritis patients with high Scr by immunofluorescence study. We postulate that the disease-associated, acquired factors at least in part contribute to the abnormal expression of CR1: elevated levels in erythrocytes and defective expression on glomeruli.     

Different abilities of two types of Fc gamma receptor on guinea-pig macrophages to trigger the phosphatidylinositol turnover.

When exposed to hen ovalbumin (OA) complexes of IgG antibodies, guinea-pig macrophages were found to augment the phosphatidylinositol (PI) turnover. This response depended on the IgG isotype of antibodies used; OA complex of IgG2 antibody (OA gamma 2) triggered it about 3 times more effectively than did OA complex of IgG1 antibody (OA gamma 1). The inhibition experiments with monoclonal antibodies to Fc gamma 1/gamma 2R and Fc gamma 2R showed that Fc gamma 2R triggered activation of the PI turnover more intensively than did Fc gamma 1/gamma 2R. The same results were also obtained by the cross-linking of Fc gamma 2Rs or Fc gamma 1/gamma 2Rs by a combination of anti-mouse IgG F(ab')2 and anti-Fc gamma 2R F(ab')2 or anti-Fc gamma 1/gamma 2R F(ab')2. As the number of Fc gamma 2R molecules per macrophage is about one-half that of Fc gamma 1/gamma 2R molecules, the ability of Fc gamma 2R to trigger the response was found to be much greater than that of Fc gamma 1/gamma 2R. Despite this difference, neither the activity of Fc gamma 2R nor that of Fc gamma 1/gamma 2R to augment the PI turnover were affected by depletion of the intracellular Ca2+ by incubating the cells with Ionomycin and EGTA, and also by the treatment with pertussis toxin.     

Can energy drinks reduce the depressor effect of ethanol? An experimental study in mice

Although the popularization of the combined use of alcoholic beverages and energy drinks (ED) containing caffeine, taurine and other substances has increased, there are no controlled experimental studies on the effects of ED alone or combined with ethanol. This work aimed at evaluating the effects of different doses of ED combined or not with ethanol, on the locomotor activity of Swiss mice. The administration of 3.57, 10.71 or 17.86 ml/kg of ED alone increased the locomotor activity of the animals in relation to a control group. Low doses of ethanol (0.5, 1.0 and 1.5 g/kg) alone or in combination with 10.71 ml/kg of ED did not affect their locomotor activity. However, the reduction of activity observed after 2.5 g/kg of ethanol was antagonized by 10.71 ml/kg of ED. Further studies on the mechanisms of this interaction are still needed.     

Synthesis and properties of thermotropic liquid-crystalline polymers containing transition metals

New thermotropic, liquid-crystalline polyesters ( 5a, b, 6a, b ) with mesogenic bipyridinediyl units were synthesized. They form complexes with Fe(II) and Cu(II) salts. Homopolyesters 5a, b , containing no metal or less than a certain amount of metal, are smectic. A nematic mesophase was observed in the case of copolyester 6a, b . The structural properties of a polyester complex 5a with Cu, as crystal, liquid-crystal and isotropic liquid, were examined by ESR.     

T cell replacing factor/interleukin 5 induces not only B-cell growth and differentiation, but also increased expression of interleukin 2 receptor on activated B-cells

A T-cell replacing factor (TRF)/interleukin-5 (IL-5) is a B-cell growth and differentiation factor. In the present study, we examined the role of TRF/IL-5 in the increase in the levels of interleukin-2 (IL-2) receptor expression on activated B-cells. High pressure liquid chromatography (HPLC)-purified TRF/IL-5 (B151-TRF) from TRF-producing T-cell hybridoma, B151K12, as well as recombinant TRF/IL-5 (rec-TRF) were used for the analysis. Maximum anti-2,4-dinitrophenyl (DNP) IgG antibody response of DNP-primed B-cells or polyclonal IgM secretion of B-cell tumor line BCL1 was seen when HPLC-purified B151-TRF was added or when suboptimal doses of B151-TRF were added to the culture in the presence of IL-2. Normal resting B-cells gave maximum anti-SRBC IgM PFC responses when HPLC-purified B151-TRF and IL-2 were present. The purified B151-TRF as well as rec-TRF also induced on B-cells increased expression of IL-2 receptors that react with monoclonal anti-murine IL-2 receptor antibody, PC61, and 125I-labelled IL-2. The numbers of functional high affinity IL-2 receptors on activated B cells increased at least 20-fold by culturing them with purified B151-TRF. Moreover, B151-TRF induced increase in the levels of steady-state mRNA for IL-2 receptor by approximately 8-fold. These results suggest that activated B-cells as well as BCL1-cells may express functional IL-2 receptors or closely related molecules when stimulated with HPLC-purified B151-TRF as well as rec-TRF.     

Differential expression of decorin and biglycan genes during palatogenesis in normal and retinoic acid-treated mice.

Proteoglycans are involved in secondary palate formation. In the present study, we focused on two small leucine-rich proteoglycans, decorin and biglycan, because they assembled extracellular matrix molecules such as collagens and modulated signaling pathway of transforming growth factor-beta. To investigate the functions of decorin and biglycan in palatogenesis, we compared their mRNA expression patterns between normal palate and retinoic acid-induced cleft palate in mice by using in situ hybridization analysis during the period of embryonic day 13.5 (E13.5) to E15.5. On E13.5, decorin mRNA was expressed in the epithelia and mesenchyme on the nasal side of the developing secondary palate. During the period the palate shelves were fusing (E14.5), decorin mRNA was strongly expressed in the mesenchyme but its expression pattern was asymmetric; decorin mRNA expression area in the nasal side was broader than that in the oral side. The expression of decorin mRNA was hardly detected in the mesenchyme on either side of the medial edge epithelium. After fusion (E15.5), its expression converged to the mesenchyme just around the palatine bone. Biglycan mRNA was ubiquitously distributed throughout the palatal mesenchyme for the mid-gestation period. Its expression area became limited to the ossification area within the palate after the late gestation period. In the retinoic acid-treated mice, the area of the decorin gene expression expanded to the core region of the palate primordium where little signal was observed in control mice. On the other hand, biglycan in the retinoic acid-treated mice did not show remarkable change in its distribution patterns compared with that in the control mice. These findings suggest that decorin and biglycan play distinct roles in palatogenesis, and decorin was more actively involved in the process of secondary palate formation than biglycan. Up-regulation of decorin gene expression in the retinoic acid-treated mice might influence the pathogenesis of cleft palate.