Genetic regulation of the expression of H-2-K.5 antigen of erythroid cells by H-2K end

Difference in the amounts of H-2K.5 antigens present on erythrocytes was observed, using quantitative absorption method, among several B 10 congenic strains. However, no such variation was seen on the lymphocytes and lung cells. The variability in the amount of this antigen on the erythrocyte surface was primarily dependent on the haplotype of the H-2K end in the B 10 recombinant strains examined. This suggests that the regulator of H-2 expression on erythrocytes is in this region. Further genetic analysis confirmed that this regulation functions in the cis-position. Finally, the H-2K.5 antigenic activity was expressed on the reticulocytes of all strains tested, but appeared lower in the type 2 group indicating that the regulation begins early in erythropoietic differentiation and eventually results in a complete loss of detectable activity.     

Association of the antibody response to hemocyanin with behavior in mice bred for or low antibody responsiveness.

Researchers attempted to find a genetic correlation between the antibody response and some behaviors by comparing the behavioral profile of good antibody-producing mice (Biozzi's H mice) with that of bad antibody producers (Biozzi's L mice). The behavioral tests used were 2 open fields, a light–darkness test, and reaction to capture; the antigen was keyhole limpet hemocyanin, and blood levels of immunoglobulin (Classes IgM and IgG) antibodies to hemocyanin were measured by diffusion-in-gel-enzyme-linked immunosorbent assay. H and L mice differed in the magnitude of the antibody response (H?>?L), in reaction to capture (L?>?H), and in rearing in 1 of the open fields (L?>?H). Yet the level of IgM or IgG antibodies was uncorrelated with those behaviors in the (H?×?L) F, hybrids and in outbred CDI mice. Thus, the behavioral differences between H and L mice are not due to the antibody response genes but to other genes fixed during selection for antibody responsiveness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic analysis of the corticosterone response to ethanol in BXD recombinant inbred mice.

The genetic control over the corticosterone response to ethanol (EtOH) and its possible relationship to other EtOH-related traits was examined using BXD recombinant inbred (RI) strains derived from an F2 cross of C57BL/6J (B6) and DBA/2J (D2) progenitor strains. Quantitative trait locus (QTL) analysis of corticosterone levels 1 hr following EtOH suggested the influence of a single major gene on this trait. Two loci were predicted to account for 47% of the genetic variance in plasma corticosterone levels 6 hr following EtOH, whereas 3 loci were predicted to account for 78% of the genetic variance in corticosterone levels 7 hrs following EtOH. Markers associated with corticosterone levels 7 hrs following EtOH and corrected corticosterone levels 6 hrs post-EtOH overlapped with ones found to influence acute and chronic EtOH withdrawal severity, suggesting some degree of common genetic determination between these traits. Overall these results indicate that gene action significantly influences stress responsiveness and suggest possible chromosomal locations of these genes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

BCG-activated NK cells regulate the antibody response to SRBC and restore immune reactivity to PPD in BCG-infected mice

C57B1/6 mice show a significant increase in the number of natural killer (NK) cells in the peritoneal cavity, four days after intraperitoneal infection with Mycobacterium bovis strain BCG. Cell transfer experiments demonstrated that BCG-induced NK cells are able to depress the induction of antibody response to an unrelated antigen (i.e., sheep red blood cells) in recipient mice. The involvement of macrophages, B and T cells in the phenomenon was ruled out by using different purification steps. In addition, BCG-induced NK cells were shown to be able of partially restoring the DTH response to PPD in recipient mice that were anergic to the latter antigen as a consequence of intravenous infection with large doses of BCG.     

High titer, prostate specific antigen-specific human IgG production by hu-PBL-SCID mice immunized with antigen-mouse IgG2a complex-pulsed autologous dendritic cells

We report here that immunization of human PBMC reconstituted SCID mice (hu-PBL-SCID mice) with in vitro cultured autologous dendritic cells (DC) pulsed with prostate specific antigen (PSA) complexed to a PSA-specific mouse IgG2a (PSA-IgG2a) consistently and reproducibly stimulates PSA-specific human IgG production. On day 0, female PBMC were used to reconstitute SCID mice and to generate DC in vitro. DC cultures were pulsed with PSA or PSA-IgG2a on day 6. The previously reconstituted hu-PBL-SCID mice were immunized with either PSA-pulsed DC and PSA, PSA-IgG2a-pulsed DC and PSA-IgG2a, or additional PBMC and PSA-IgG2a on day 7. Mice immunized with PSA-IgG2a-pulsed DC had, on the average, up to 31.5 times greater PSA-specific IgG serum concentrations than control mice. Competition ELISA confirmed the PSA specificity of serum IgG. Immunoblot analysis suggested that sera IgG preferentially recognized conformational epitopes on PSA. Therefore, our results represent a major step toward cloning human tumor-associated Ag-specific human mAbs from hu-PBL-SCID mice. In addition, flow cytometry showed that PSA-pulsed DC express significantly more B7.1, B7.2, CD40, and MHC class II surface molecules than mock-treated DC, but PSA-IgG2a-pulsed DC only had significantly enhanced B7.2 surface expression. Interestingly, PSA-specific IgG responses were reproducibly stimulated by DC expressing more B7.2, a molecule associated with Th2-type immune deviation, but not by those expressing more B7.1 and CD40, molecules associated with Th1-type immune deviation. Thus, our results show that stimulation with either Ag or Ag complexed to mAb yields DC with different phenotypes and APC effector functions.     

Peptide mimotopes displayed by phage inhibit antibody binding to bet v 1, the major birch pollen allergen, and induce specific IgG response in mice

The major birch pollen allergen Bet v 1 is one of the most extensively characterized allergens both on the molecular and the immunological level. To define conformational B cell epitopes on Bet v 1, we screened filamentous phage libraries expressing circular or linear nonapeptides to select ligands specific for anti-Bet v 1 murine monoclonal antibodies BIP1 and BIP4. The deduced amino acid sequence of the BIP1 ligand was CFPYCYPSESA, and of the BIP4-ligand, CRQTRTMPGC. Both sequences derived from the circular phage library. Alignments to the sequence of Bet v 1 showed no similarities, indicating that the antibodies most likely recognize discontinuous epitopes. Phages displaying these mimotopes were capable of inhibiting interactions of the anti-Bet v 1 monoclonals with Bet v 1 in a dose-dependent manner in ELISA. In contrast, sequence-identical synthetic peptides were ineffective in blocking the antibody-allergen interactions. This is in agreement with the conformational inhomogeneity of the peptides in solution as observed by nuclear magnetic resonance spectroscopy. Intragastric administration of phages expressing the BIP1 mimotope induced a Bet v 1-specific IgG response in Balb/c mice. We conclude that peptide mimotopes, when displayed on phages, may induce a protective IgG response preventing IgE-mediated allergic reactions, suggesting a possible clinical application.     

The immunoglobulin (IgG) antibody response to OspA and OspB correlates with severe and prolonged Lyme arthritis and the IgG response to P35 correlates with mild and brief arthritis

In an effort to implicate immune responses to specific Borrelia burgdorferi proteins that may have a role in chronic Lyme arthritis, we studied the natural history of the antibody response to B. burgdorferi in serial serum samples from 25 patients monitored throughout the course of Lyme disease. In these patients, the immunoglobulin G (IgM) and IgG antibody responses to 10 recombinant B. burgdorferi proteins, determined during early infection, early arthritis, and maximal arthritis, were correlated with the severity and duration of maximal arthritis. The earliest responses were usually to outer surface protein C (OspC), P35, P37, and P41; reactivity with OspE, OspF, P39, and P93 often developed weeks later; and months to years later, 64% of patients had responses to OspA and OspB. During early infection and early arthritis, the levels of IgG antibody to P35 correlated inversely with the subsequent severity or duration of maximal arthritis. In contrast, during periods of maximal arthritis, the levels of IgG antibody to OspA and OspB, especially to a C-terminal epitope of OspA, correlated directly with the severity and duration of arthritis. Thus, the higher the IgG antibody response to P35 earlier in the infection, the milder and briefer the subsequent arthritis, whereas during maximal arthritis, the higher the IgG response to OspA and OspB, the more severe and prolonged the arthritis.     

The murine (H-2k) T-cell epitopes of bee venom phospholipase A2 Lie outside the active site of the enzyme. Implications with respect to a paracrine activation of Th2 cells for an IgE antibody response

A 51-year-old drunken male was carried to a hospital with acute abdominal pain and was suspected of acute pancreatitis. The patient was treated with fasting, electrolyte transfusion, and anodyne, but took a sudden turn for the worse and died in 16 hours. In the judicial autopsy, rupture of a small intestine was detected. As the police investigated, he had been kicked in the abdomen by an assailant before coming to the hospital. The cause of death was diagnosed to be acute peritonitis due to the rupture of a small intestine. Several problems were pointed out on medical examinations and treatments of this case.     

Detection of IgG antibody to Epstein-Barr virus viral capsid antigen in saliva by antibody capture radioimmunoassay

In order to characterize the cochlear transducer nonlinearities which are involved in the generation of the summating potential (SP), we investigated the effect of a change in the electrical operating point of the cochlear transducer on the SP. The electrical operating point of the cochlear transducer was affected by suppressing reversibly the endocochlear potential (EP). This was realized by intravenous injection of furosemide in guinea pig. A differential recording technique was used in the basal turn of the cochlea to measure locally generated even-order distortion products: the SP and the second harmonic component (2F0) of the cochlear microphonics (CM). These potentials were evoked by 2 and 8 kHz stimuli presented at 60 dB SPL. Following furosemide injection, the SP changed polarity twice over time. The zero crossings of the SP coincided with a minimum in the amplitude of 2F0. Concomitantly, the phase of 2F0 shifted about 120 degrees. The changes in the electrical even-order products were comparable to the changes that occurred in a mechanical even-order intermodulation distortion product (the difference tone F2-F1 otoacoustic emission) after furosemide application (Mills et al., J. Acoust. Soc. Am. 94 (1993) 2108-2122). The combined results suggest that only one sigmoidal transfer function may account for the SP, 2F0, and the emission of the difference tone F2-F1, and that shifts in the operating point of the transfer function would be the major cause behind the furosemide-induced changes in the even-order distortion products. The sigmoidal transfer function is likely associated with the mechano-electrical transducer channel at the apical pole of the outer hair cell.     

Regulation by the H-2 gene complex of macrophage-lymphoid cell interactions in secondary antibody responses in vitro

The ability of antigen-bearing syngeneic and allogeneic peptone-induced peritoneal exudate macrophages to support development of primary and secondary antibody responses by murine lymphoid or spleen cells in vitro has been investigated. The antigen used was the terpolymer of L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT). Syngeneic and allogeneic macrophages supported development of comparable primary antibody responses to GAT, indicating that genetic restrictions do not limit efficient macrophage-lymphocyte interactions in primary responses. By contrast, immunized spleen or lymphoid cells developed secondary antibody responses preferentially when stimulated in vitro with GAT on macrophages syngeneic to the macrophages used to present GAT during in vivo immunization. Thus, genetic restrictions regulate efficient macrophage-lymphocyte interactions in secondary antibody responses. These restrictions have been demonstrated from 2 to 8 wk after a single immunization with limiting quantities of GAT and are controlled by the H-2 gene complex. The implications that immune lymphocytes selectively recognize and respond to antigen presented in the context of the macrophage membrane-antigen complex which sensitized the lymphocytes initially are considered.     

Beta2-microglobulin-deficient NK cells show increased sensitivity to MHC class I-mediated inhibition, but self tolerance does not depend upon target cell expression of H-2Kb and Db heavy chains

Mice lacking beta2-microglobulin (beta2m- mice) express greatly reduced levels of MHC class I molecules, and cells from beta2m- mice are therefore highly sensitive to NK cells. However, NK cells from beta2m- mice fail to kill beta2m- normal cells, showing that they are self tolerant. In a first attempt to understand better the basis of this tolerance, we have analyzed more extensively the target cell specificity of beta2m- NK cells. In a comparison between several MHC class I-deficient and positive target cell pairs for sensitivity to beta2m- NK cells, we made the following observations: First, beta2m- NK cells displayed a close to normal ability to kill a panel of MHC class I-deficient tumor cells, despite their nonresponsiveness to beta2m- concanavalin A (Con A)-activated T cell blasts. Secondly, beta2m- NK cells were highly sensitive to MHC class I-mediated inhibition, in fact more so than beta2m+ NK cells. Thirdly beta2m- NK cells were not only tolerant to beta2m- Con A blasts but also to Con A blasts from H-2Kb-/Db- double deficient mice in vitro. We conclude that NK cell tolerance against MHC class I-deficient targets is restricted to nontransformed cells and independent of target cell expression of MHC class I free heavy chains. The enhanced ability of beta2m- NK cells to distinguish between MHC class I-negative and -positive target cells may be explained by increased expression of Ly49 receptors, as described previously. However, the mechanisms for enhanced inhibition by MHC class I molecules appear to be unrelated to self tolerance in beta2m- mice, which may instead operate through mechanisms involving triggering pathways.     

Differential regulation of in vitro cytokine production by human blood cells in response to methylmethacrylate

The effect of methylmethacrylate (MMA) on human whole blood cultures (WBC) obtained from healthy donors was investigated. Lymphocyte transformation and cytokine production, that is, interleukin 6 (IL-6), interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha), were used to evaluate the immunological activities of MMA. Primary cytotoxicity testing of MMA in Jurkat cells showed that this compound decreased the cell proliferation to 50% at a concentration of >60 mmol/L. Similarly, MMA significantly decreased lymphocyte transformation in either phytohemagglutinin (PHA) or Staphylococcus aureus protein A (SpA) activated WBC at 100 mmol/L. In contrast to activated WBC, MMA had no observed effect on resting blood cells. Cytokine expression in WBC seemed differentially modulated by MMA. There was a tendency for IL-6 production in both resting and PHA-stimulated WBC to be upregulated, while IL-6 induced in SpA stimulated cultures was downregulated. TNF-alpha was slightly increased by MMA in resting WBC at early incubation periods, and it was slightly downregulated in response to PHA or SpA activation. Suppression of IFN-gamma secretion was observed in WBC with or without PHA or SpA stimulation. The overall results demonstrated that MMA at physiological levels could influence the cytokine production in normal human blood cells in vitro. Alterations of cytokine production patterns by MMA indicate that this compound has multiple regulatory effects on immune reactions in normal human blood.     

Inheritance of antibody specificity: the IgM anti-lipopolysaccharide response in mice

Double contrast arthrography of the knee is the method of choice for visualization of the menisci, while the single positive contrast technique is the preferred method for evaluation of the cruciate ligaments. A technique is described which combines the advantages of these two methods. Following radiography of the menisci, an essentially single positive contrast study of the cruciate ligaments is obtained by positioning the patient in the lateral recumbent position with the knee flexed to about 90degree. The positive contrast medium in this position fills the joint cavity beyond its mid-point and surrounds the cruciate ligaments. Tomographic studies of the midline of the knee joint, made in this position with a polytome unit, demonstrate the cruciate ligaments to best advantage.     

Primary structure of the murine monoclonal IgG2a antibody mAb735 against alpha (2-8) polysialic acid. 2. Amino acid sequence of the heavy (H-) chain Fd' region

The complete amino acid sequence of the Fd' region including the VH part, the CH1 domain, and the hinge segment of the biologically relevant monoclonal mouse anti-alpha (2-8) polysialic acid antibody mAb735 is presented. The reduced and carboxymethylated H-chain was digested with trypsin and cyanogen bromide. For subfragmentation selected peptides were cleaved with thermolysin and endoproteinase Asp-N. The generated peptides were isolated by RP-HPLC and characterized by sequence analysis, plasma desorption mass spectrometry (PDMS), and amino acid analysis. The N-terminal sequence was determined after enzymatic deprotection with pyroglutamate aminopeptidase. According to Kabat et al. the variable region of the H-chain belongs to the subgroup II. Sequence data from the constant region indicate that mAb735 represents the gamma 2a isotype.     

Bcl-2参与SCID小鼠体内齐墩果酸诱导HL-60细胞凋亡的调控作用

目的:观察齐墩果酸(OA)对白细胞移植模型小鼠脾脏浸润白血病细胞凋亡数量和Bcl-2蛋白表达的影响,探讨OA对白血病模型鼠的治疗作用机制.方法:取浓度为2×107mL-1体外培养的人早幼粒系白血病HL-60细胞0.5 mL,腹腔注射重症联合免疫缺陷(SCID)小鼠,构建SCID小鼠的HL-60细胞移植瘤模型;模型成功后小鼠分为用药组、白血病模型对照组,并设正常对照组.用药组以200 mg·kg-1OA皮下注射,用药2周后观察各组小鼠的一般状态、外周血象及骨髓象白细胞分类情况,病理学检查脾白血病细胞浸润程度,TUNEL方法测定脾浸润白血病细胞凋亡率,免疫组织化学检测HL-60细胞凋亡相关基因Bcl-2蛋白表达率.结果:成功建立SCID小鼠的HL-60细胞移植瘤模型;用药组小鼠体质量[(15.0±0.8) g]明显高于模型组小鼠[(13.9±0.9) g](P<0.01),小鼠生存期[(50.3±5.5) d]明显高于模型组小鼠[(37.1±4.4) d](P<0.01);与模型组比较,用药组外周血白血病细胞有向正常白细胞分化趋势,可见分叶的白血病细胞,骨髓象中幼稚细胞减少,脾浸润情况改善;用药组小鼠脾浸润白血病细胞凋亡率高于模型组(P<0.01),Bcl-2蛋白表达阳性细胞百分率低于模型组(P<0.01).结论:成功建立白血病移植瘤鼠模型;OA可改变白血病移植瘤模型鼠的一般状态,延长生存期;OA通过降低Bcl-2表达可诱导白血病细胞凋亡.     

Neutralization of TNF by the antibody cA2 reveals differential regulation of adhesion molecule expression on TNF-activated endothelial cells

Upregulation of adhesion proteins plays an important role in mediating inflammation. The induction of adhesive molecules has been well studied, but the reversibility of their expression has not been well characterized. A neutralizing anti-TNF monoclonal antibody (cA2) was used to study the down regulation of TNF-induced E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) on cultured human umbilical vein endothelial cells (HUVECs). Addition of cA2 following TNF stimulation of HUVECs enhanced the rate of E-selectin and VCAM-1 down-regulation from the cell surface and also reduced steady state E-selectin and VCAM-1 mRNA levels. The cA2-mediated disappearance of E-selectin, but not VCAM-1 protein was microtubule and not microfilament dependent. Neutralization of TNF only slightly reduced ICAM-1 cell surface levels following initial TNF stimulation, suggesting a slower turnover of ICAM-1 compared to E-selectin and VCAM-1. Microtubule inhibition during TNF stimulation partially inhibited E-selectin, VCAM-1 and ICAM-1 mRNA upregulation. VCAM-1 and ICAM-1 cell surface expression were similarly partially inhibited, however, E-selectin levels were unaffected, presumably due to the dual, opposing effect of inhibiting protein expression and inhibiting internalization. Microfilament inhibition during protein induction specifically inhibited the maximal expression of VCAM-1 protein and mRNA, without affecting E-selectin or ICAM-1. These data support the notion that E-selectin, VCAM-1, and ICAM-1 expression are differentially regulated on HUVECs and suggest that TNF neutralizing therapies may be effective because of their ability to reduce the levels of pre-existing adhesion proteins.     

Comparison of the T cell-independent antibody response of mice and rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

In a prospective population-based cohort study, we assessed whether bone mineral density (BMD) measurements of perimenopausal women and other risk factors for osteoporosis are predictive of subsequent fracture. Women aged 47-51 years chosen randomly from a population register who underwent a bone density measurement 2 years previously were followed up by questionnaire to assess the 2-year incidence of any self-reported fractures. We found that 44 women, out of 1857 who completed the questionnaire, sustained at least one fracture within a 2-year follow-up period. After adjustment for covariates, the odds ratio of sustaining a fracture was 1.6 (95% confidence interval [CI] 1.16-2.34) for every standard deviation reduction in BMD at the spine, for women with a prior history of fracture the odds ratio of a subsequent fracture was approximately 2 (95% CI 1.31-3.03), a family history of hip fracture (maternal grandmother) carried an odds ratio of 3.7 (95% CI 1.55-8.85), while being postmenopausal or having a hysterectomy resulted in an odds ratio of 1.98 (1.02-3.56). This study has shown that BMD measurements at the hip and spine and other risk factors predict any nonhip and nonspine perimenopausal fractures. Further follow-up is required to assess the predictive performance of BMD measurements and other risk factors for hip and spine fractures.