An anti-okadaic acid-anti-idiotypic antibody bearing an internal image of okadaic acid inhibits protein phosphatase PP1 and PP2A catalytic activity

Okadaic acid (OA), produced by marine phytoplankton, is the parent compound of a family of marine toxins responsible for diarrheic shellfish poisoning (DSP). A monoclonal antibody to OA (6/50) (Ab1) has been raised and in turn used for immunization of syngeneic animals. Mice inoculated with the 6/50 idiotype produced both anti-idiotypic antibodies (Ab2) and OA binding antibodies (Ab3). The selected anti-idiotypic antibody 1/59 bound to the immunizing 6/50 idiotype but not to F(ab')2 fragments of pooled normal mouse Ig. It inhibited the binding of OA to solid-phase attached F(ab')2 of 6/50 IgG as well as the binding of 6/50 IgG to a solid-phase bound OA. Like OA, 1/59 anti-idiotypic antibody inhibited protein phosphatase 1 and 2A catalytic subunits in a 32P-phosphorylase a phosphatase radioassay. Thus, 1/59 IgG is a novel internal image anti-idiotypic antibody (Ab2 beta) and can serve as a surrogate of OA in biological assays.     

Characterization of allergoids from ovalbumin in vitro and in vivo

Several in vivo and in vitro methods for monitoring immunological properties of two allergoids obtained by formaldehyde treatment of ovalbumin (OA) were developed. The calculated molecular weight of allergoids was 80 kD (OA-F1) and 165 kD (OA-F2), respectively. The allergenic activity in vitro of allergoids in mast-cell histamine release assay was 1000 times lower than of OA. Both allergoids showed reduced ability to induce passive cutaneous anaphylaxis in the Sprague-Dawley rats or systemic anaphylaxis in Dunkin-Harley guinea-pigs. The ability of OA and allergoids to bind to the OA-specific IgE antibodies was measured in vivo by the inhibition of passive cutaneous anaphylaxis (PCA-inhibition). Allergoid binding to IgE was 51-66% lower than the native allergen. Moreover, the avidity of OA-specific IgG antibodies, measured by ELISA-inhibition, for allergoids and allergen was of the same order. Allergoids induced a different pattern of humoral immune response from that, induced by the native allergen. Thus, after immunization of BALB/c mouse, both allergoids induced a higher production of IgG and a lower production of IgE than OA, only OA-F2 induced a lower production of IgG1. The differences in the IgA response to the immunogens was not significant. Delayed hypersensitivity studies in the BALB/c mouse showed that allergoids were 5- to 12-times less effective in inducing a cell-mediated immune response than OA. The present study provides a battery of immunological methods for preclinical testing of modified allergens.     

Isotype-specific immune response to a single hepatitis C virus core epitope defined by a human monoclonal antibody: diagnostic value and correlation to PCR

In this study we tested the seroreactivity of 223 selected anti-HCV-reactive blood donors to the human B-cell epitope N-VYLLPR-C (C34-39) of the hepatitis C virus core antigen. The epitope was recently identified and characterized by the human monoclonal IgG antibody Ul/F10 and is located within the amino acid residues 34-39 of the aminoterminal core region. The blood donor sera were selected from anti-HCV ELISA (Ortho, 2nd generation)-reactive samples. Sixty-seven of these sera were further reactive in RIBA (Ortho, 2nd generation). According to their RIBA pattern, these samples were divided into four groups. Samples in the first group (n = 18) reacted to all four recombinant HCV antigens. The samples of the second (n = 9) and third group (n = 8) reacted to c22-3/c33c and c22-3/c100-3, respectively. Sera from group 4 (n = 32) showed a RIBA indeterminate pattern with reactivity only to c22-3. All 223 samples were analyzed for anti-C34-39 antibodies by ELISA, and the 67 RIBA-reactive samples were additionally tested for the presence of HCV RNA by RT/PCR. In groups 1 and 2, over 80% of the samples showed anti-C34-39 reactivity which was restricted to the IgG1 isotype. In contrast, in groups 3 and 4, antibodies to the epitope C34-39 were detected in less than 10% of the samples. Interestingly, the anti-C34-39 response correlates with the presence of HCV RNA; 95.5% of the samples had coincident results in all subgroups. None of the RIBA-negative sera showed a specific seroreaction to the C34-39 peptide.     

Influence of adjuvants on the induction of autoantibodies to the thyrotropin receptor

To determine the influence of adjuvant on the induction of antibodies to thyrotropin receptor (TSHR), we immunized BALB/c mice with a extracellular domain of the TSHR (ETSHR) protein in complete Freund's adjuvant (CFA), Titer Max (TM) and Gerbu. Similarly, control groups of mice were immunized with bovine serum albumin (BSA) in each of the different adjuvants. As determined by ELISA, ETSHR given along with CFA elicited high titers of antibodies to ETSHR which were mainly restricted to the IgG1 subclass. Mice immunized with ETSHR in TM also developed high titers of anti-ETSHR antibodies but had higher levels of both IgG1 and IgG2a. However, immunization with ETSHR in Gerbu resulted in low titers of antibodies, restricted to IgG1 subclass. Immunization of mice with BSA in each of the three adjuvants induced higher antibody titers to BSA. The subclass of antibodies in mice immunized with BSA in CFA and TM were predominantly IgG1 and IgG2a with lower levels of IgG2b, whereas in Gerbu treated group, antibody to BSA was restricted to IgG1 subclass. Analysis of specificity of antibodies against ETSHR, in mice immunized with ETSHR, revealed that irrespective of the adjuvant used, the dominant reactivity was against peptide 1 (AA 22-41) with weaker reactivity against several other. peptides. The only exception was in mice immunized with ETSHR in TM which also showed significant reactivity against peptide 23 (AA 352-371). Mice immunized with the ETSHR in CFA or in TM showed elevated levels of serum TSH binding inhibitory immunoglobulins (TBII). However, mice immunized with ETSHR in Gerbu, which had lower titers of antibodies to ETSHR, showed normal TBII levels. These studies showed that adjuvant composition could influence the titer, subclass and fine specificity of antibodies to ETSHR which in turn could affect the development of TBII activity.     

Estrogen replacement therapy and worsening of radiographic knee osteoarthritis: the Framingham Study

OBJECTIVE: To examine whether estrogen replacement therapy (ERT) prevents worsening of radiographic knee osteoarthritis (OA) in elderly women. METHODS: A total of 551 women ages 63-91 years (mean age 71) in the Framingham Study were followed up from biennial examination 18 (1983-1985) to examination 22 (1992-1993). Data on postmenopausal ERT were obtained every 2 years. Subjects were classified into 3 groups according to their estrogen use at biennial examination 18: never users (n = 349), past users (n = 162), and current users (n = 40). Women received anteroposterior weight-bearing knee radiographs at examinations 18 and 22. Using the Kellgren and Lawrence criteria, global radiographic knee OA was assessed, (grade range 0-4) and individual radiographic features, such as osteophytes and joint space narrowing, were scored from 0 to 3. Worsening was defined as either development of radiographic OA that was not present at baseline (incident OA) or progression of baseline radiographic OA by > or =1 Kellgren and Lawrence grade (progressive OA). Potential confounding factors included age, body mass index, weight change, smoking, knee injury, physical activity level, and bone mineral density at the femoral neck. RESULTS: During 8 years of followup, 17.4% of knee radiographic scores worsened by 1 grade and 5.8% by 2 or 3 grades among never users of ERT. Among current estrogen users, only 11.7% of knee radiographic scores worsened by 1 grade and none worsened by more than 1 grade. After adjusting for age and other potential confounding factors, the relative risk of incident radiographic knee OA in comparison with never users of estrogen was 0.8 (95% confidence interval [95% CI] 0.5-1.4) in past users and 0.4 (95% CI 0.1-3.0) in current users. Current use of estrogen also showed a trend toward decreased risk of progressive knee OA compared with never use (odds ratio [OR] 0.5, 95% CI 0.1-2.9). When both incident and progressive radiographic knee OA cases were combined, current ERT use had a 60% decreased risk compared with never use (OR 0.4, 95% CI 0.1-1.5). CONCLUSION: This is the first prospective cohort study to examine the effects of ERT on radiographic knee OA. The results indicate that current use of ERT had a moderate, but not statistically significant, protective effect against worsening of radiographic knee OA among elderly white women. These findings corroborate those of cross-sectional studies and point further to a potential benefit of female hormones in OA.     

Analysis of autoantibody epitopes on steroid 21-hydroxylase using a panel of monoclonal antibodies

A panel of five mouse monoclonal antibodies (MAbs) to human recombinant steroid 21-hydroxylase (21-OH) were produced, characterized, and used to study the interaction of 21-OH autoantibodies (AAbs) with different epitopes on human 21-OH. AAbs in patients with isolated autoimmune Addison's disease, autoimmune polyglandular syndromes types I and II, and 21-OH antibody-positive patients without overt Addison's disease (25 patients in total) were studied. Four MAbs were IgG1 subclass, one was IgG2a, and all had kappa light chains. The affinities of four of the antibodies were in the range 2.0 x 10(8) M(-1) to 7.0 x 10(8) M(-1), and the affinity of the other was 2.3 x 10(7) M(-1) 21-OH MAbs did not cross-react with 17alpha-hydroxylase (17alpha-OH)) or P450 side chain cleavage enzyme. Studies using a series of 21-OH fragments allowed the identification of short stretches of amino acids (AA) that were involved in forming the MAb binding sites. AA 391-405, defined as epitope region (ER) 1, were found to be important for binding of M21-OH1 and M21-OH2, AA 406-411 (ER2) were important for M21-OH3 and M21-OH4 binding, and AA 335-339 (ER3) for M21-OH5 binding. In addition, MAb Fab or F(ab')2 fragments were used to study 21-OH AAb epitopes in competition experiments. These investigations demonstrated that 21-OH AAbs recognize similar epitopes to the MAbs, with ER2 and ER3 being part of two distinct major epitopes, and ER 1 being part of a minor epitope. Mixtures of M21-OH antibody Fab or F(ab')2 fragments caused almost complete inhibition (80%-95%) of AAb binding in 24 out of 25 sera, and in the case of the remaining serum, the effect was marked but incomplete (67% inhibition). There were no major differences between the binding characteristics of AAbs from patients with different forms of autoimmune adrenal disease. All five 21-OH MAbs reacted with human adrenal tissue in an immunofluorescence test, but only M21-OH1 and M21-OH2 reacted with bovine adrenal tissue in these experiments. None of the MAbs reacted with human ovarian tissue in an immunofluorescence test. Overall, these studies indicate that 21-OH AAbs bind to at least three different epitopes in the C-terminal part of 21-OH, and two of these epitopes appear to be human 21-OH specific.     

Maternal transmission of human immunodeficiency virus-1

We have analysed the binding of variable domain-identical mouse monoclonal antibodies (mAb) of the IgG3, IgG1 and IgG2b subclasses, as well as F(ab')2 fragments derived from the IgG3 and IgG1 mAb, to a multivalent glycoprotein target. Using a biosensor device (BIAcore, Pharmacia Biosensor) that measures the mass of the antibody (or other receptor molecule) deposited on a sensor chip displaying the relevant epitopes, we found that the IgG3 mAb binds more effectively than the other antibody species at a high but not a low epitope density. The greater functional affinity associated with the IgG3 mAb, at high epitope density, was correlated with both slower dissociation rate constants and faster association rate constants in comparison with the IgG1 and IgG2b mAb and the F(ab')2 fragments derived from the IgG3 and IgG1 mAb. Evidence for slower dissociation kinetics for the IgG3 mAb versus the IgG1 and IgG2b mAb was also obtained by ELISA and flow cytometry. These results demonstrate that: (1) differences in heavy chain constant (CH) domains can significantly influence apparent functional affinity for multivalent antigen, as determined without the use of covalently modified primary or secondary antibodies; (2) differences in CH domains can alter both association and dissociation rate constants for interactions between IgG antibodies and multivalent antigen; and (3) these effects of CH domains depend on epitope density. The effect of constant region differences on the apparent association rate constants suggests new approaches for achieving better binding or functional effectiveness through antibody engineering.     

Human immunoglobulin M paraproteins cross-reactive with Neisseria meningitidis group B polysaccharide and fetal brain

Three hundred fifty-nine serum samples from patients with immunoglobulin M (IgM) or IgG monoclonal gammopathies were tested for binding to the capsular polysaccharide (PS) of Neisseria meningitidis group B (MenB PS, poly-alpha[2-->8]-N-acetylneuraminic acid). Of 159 IgM paraproteins, 7 (4.4%) were positive, compared with 0 of 200 IgG paraproteins (P < 0.05). Since MenB PS reactivity was limited to the IgM paraproteins, the 159 IgM paraproteins were tested by enzyme-linked immunosorbent assay (ELISA) for reactivity with seven other bacterial PSs. None reacted with meningococcal A or C, Haemophilus influenzae type b, or Streptococcus pneumoniae type 3, 6, 14, or 23 PS. The specificity of the MenB PS-reactive antibodies was confirmed by demonstration of binding to N. meningitidis group B cells but not to a capsular PS-deficient mutant and by specific inhibition of binding to solid-phase MenB PS by soluble MenB PS in an ELISA. Five of five antibodies tested protected infant rats from bacteremia caused by Escherichia coli K1, an organism with a PS capsule that also is composed of poly-alpha[2-->8]-N-acetylneuraminic acid. Each of the seven MenB PS-reactive paraproteins had autoantibody activity as defined by binding to homogenates of calf brain in a radioimmunoassay. For six of the seven antibodies, binding to calf brain was inhibited by the addition of soluble MenB PS. Thus, approximately 4% of human IgM paraproteins have autoantibody activity to poly-alpha[2-->8]-N-acetylneuraminic acid, an antigen expressed in fetal brain and cross-reactive with the MenB capsular PS. The reason for this skewing of the IgM paraprotein repertoire toward reactivity with poly-alpha[2-->8]-N-acetylneuraminic acid antigenic determinants is unknown.     

Cloning of follistatin-related protein as a novel autoantigen in systemic rheumatic diseases

In an attempt to identify autoantigens of synovium in rheumatoid arthritis (RA), we constructed lambda phage expression cDNA libraries from synovium and screened them by IgG purified from synovial fluids, both of which were derived from RA patients. As a result of this unique combination of the libraries and probes, we cloned follistatin-related protein (FRP) as a novel autoantigen in systemic rheumatic diseases. FRP is a secreted protein containing a similar amino acid sequence to follistatin, an inhibitor of activin. FRP was first cloned as a transforming growth factor-beta1-inducible protein (called TSC-36) from a mouse osteoblastic cell line and was suggested to have some roles in the negative regulation of cellular growth. Immunoblotting analyses detected synovial fluid and serum anti-FRP antibodies of IgG class more frequently in RA than any other systemic rheumatic diseases and controls. Synovial fluid anti-FRP antibodies appeared in 44% of RA (n = 18) and none of osteoarthritis (OA) (n = 15) patients. Serum antibodies were detected in 30% of RA (n = 67), 17% of systemic sclerosis (n = 18), 10% of systemic lupus erythematosus (n = 51) and Sj?gren's syndrome (n = 10), and none of polymyositis/dermatomyositis (n = 13) patients and healthy subjects (n = 30). These antibodies recognized an EC domain, an extracellular Ca2+ binding module. In anti-FRP antibody-positive RA patients, serum C-reactive protein level and erythrocyte sedimentation rate were more elevated than negative patients (P < 0.05 and P < 0.01, respectively). FRP gene expression was higher in RA than OA synovium (P < 0.05). However, there was no difference between these groups in the amount of synovial FRP, suggesting its elevated turnover in RA. As follistatin inhibits activin, FRP might inhibit some growth factor-like molecule. Detection of anti-FRP antibodies, possibly having disease-promoting effects as the blocking antibodies, could be one of the markers for clinical evaluation of systemic rheumatic diseases.     

Analytical and clinical relationships between human IgG autoantibodies to beta 2 glycoprotein I and anticardiolipin antibodies

OBJECTIVE: To examine IgG anti-beta 2 glycoprotein I (anti-beta 2 GPI) binding in 82 sera referred for anticardiolipin antibody (aCL) testing and to develop preliminary clinical correlations with antiphospholipid syndrome (APS). METHODS: Immunoassay of IgG cofactor dependent aCL and IgG anti-beta 2 GPI antibodies and retrospective chart review. RESULTS: Forty-four sera exhibited normal (< or = 22 GPL units) aCL activity, 18 had moderate binding activity (23-45 GPL units), and 20 had high (> or = 46 GPL units) binding activity to cardiolipin. Among these groups, 6 of the 20 sera in the high GPL group had elevated anti-beta 2 GPI. This correlated strongly with 2 or more clinical manifestations of APS. CONCLUSION: Anti-beta 2 GPI activity may be a more valuable indicator of APS than aCL.     

Role of paraventriculo-spinal pathway in the inhibition of renal sympathetic nerve activity induced by blood volume expansion in rabbits

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized in part by the presence of tissue-bound and circulating antibodies (mostly of IgG) to the basement membrane zone (BMZ). We previously reported that IgG subclasses of BP antibodies were IgG1, IgG2 and IgG4, and that only BP IgG1 fixed complements. In this study, we examined whether BP IgG sub-classes bound to the same epitope of BP antigen or a different epitope. In an inhibition immunofluorescence studies, the complement fixing capability of IgG1 was inhibited by the pretreatment with IgG4 and partially inhibited by IgG2. On immunoblot analysis, IgG1 and IgG4 were bound to the same MW of BP antigen. In enzyme-linked immunosorbent assay (ELISA), the binding capability of IgG subclass fractions from patients with BP to synthetic peptide P1-2, exceeding normal IgG subclass fractions was seen in five IgG1, one IgG2 and two IgG4, from eight BP patients. The binding capability of IgG subclass fractions from the patients with BP to P1-1, exceeding the normal IgG fractions was seen in two IgG1, three IgG2 and one IgG4 from ten BP patients. On inhibition ELISA, the binding activity to P1-2 of IgG4 was partially inhibited by the pretreatment of IgG1 and IgG2. These findings suggest that BP IgG1, IgG2 and IgG4 could bind to the same epitope though considerable variation occurred between patients.     

Effect of methanol, ethanol, dimethyl sulfoxide, and acetonitrile on in vitro activities of cDNA-expressed human cytochromes P-450

The effects of methanol, ethanol, dimethyl sulfoxide (DMSO), and acetonitrile were studied in vitro on nine individual, cDNAexpressed cytochrome P-450 activities (phenacetin O-deethylase for CYP1A1 and CYP1A2, coumarin 7-hydroxylase for CYP2A6, testosterone 6beta-hydroxylase for CYP3A4, 7-ethoxy-4-trifluoromethylcoumarin deethylase for CYP2B6, paclitaxel 6alpha-hydroxylase for CYP2C8, diclofenac 4'-hydroxylase for CYP2C9, S-mephenytoin 4-hydroxylase for CYP2C19, and (+/-)-bufuralol 1'-hydroxylase for CYP2D6) in commercially available human lymphoblastoid microsomes. These data show that specific solvents have enzyme-selective effects on P-450 activities. Methanol did not substantially inhibit (相似文献   

Interleukin-8 differentially modulates interleukin-4- and interleukin-2-induced human B cell growth

The effect of interleukin-8 (IL)-8 on human B cell growth, as determined by thymidine uptake and viable cell numbers was studied. IL-8 inhibited IL-4-induced growth of B cells costimulated with anti-mu antibodies (Ab) or Staphylococcus aureus Cowan strain I (SAC) in a dose-dependent fashion. In contrast, IL-8 did not inhibit IL-2-induced growth of B cells. The IL-8-mediated inhibition was specific, since it was blocked by anti-IL-8 mAb but not by control IgG1. Moreover, anti-tumor necrosis factor-alpha (anti-TNF-alpha) Ab blocked IL-8-mediated inhibition. On the other hand, TNF-alpha, but not other cytokines including IL-1 beta, IL-3, IL-5, IL-6, interferon-alpha (IFN-alpha) or IFN-gamma, inhibited IL-4-mediated growth, and inhibition by TNF-alpha was blocked by anti-TNF-alpha Ab but not by control IgG. IL-4 had no effect on TNF-alpha binding by B cells while it decreased TNF-alpha production by B cells. IL-8 had no effect in binding of IL-4, IL-2 or TNF-alpha by B cells, however, it enhanced TNF-alpha production by B cells. These results indicate that IL-8 inhibited IL-4-induced human B cell growth by enhancement of endogenous TNF-alpha production.     

IgG2 subclass restriction of anti-beta 2 glycoprotein 1 antibodies in autoimmune patients

The IgG subclass and light chain distribution of antiphospholipid antibodies (aPL) occurring in autoimmune patients were determined by means of two radioimmunoassays using either cardiolipin- or beta 2 glycoprotein 1 (beta 2GP1)-coated microtitre plates and mouse MoAbs. Of 50 sera selected for positivity of anticardiolipin antibodies (ACA) of the IgG isotype, 32 (64%) possessed anti-beta 2GP1 antibodies and their presence was closely associated with clinical features of the antiphospholipid syndrome. Good correlations were found between ACA and anti-beta 2GP1 antibodies when considering antibody level and patterns of light chain and IgG subclass, suggesting that, overall, the same antibodies were being measured. Light chain analysis showed the polyclonal origin of these antibodies and, in most sera, a trend towards use of lambda chain. Among sera positive for anti-beta 2GP1 antibodies, IgG2 was the major subclass reactive with beta 2GP1 and cardiolipin (87% and 74% of the IgG antibody activity, respectively). In contrast, in the group of 18 sera lacking anti-beta 2GP1 antibodies, ACA were largely restricted to IgG3, with a lesser contribution by IgG1. A few selected sera from the anti-beta 2GP1-positive group were shown to contain mixtures of antibodies that required beta 2GP1 (restricted to IgG2 present in large amounts) and did not require this cofactor (restricted to IgG3 and/or IgG1 present in low amounts) for their reactivity with cardiolipin. There was no contribution of glycosylation to the epitopes recognized by anti-beta 2GP1 antibodies, even though human anti-carbohydrate antibodies are restricted to the IgG2 subclass. These findings further emphasize the intra- and interindividual heterogeneity of aPL, and should help to discriminate clinically relevant specificies.     

Occupational exposure to organic solvents and sleep-disordered breathing

STUDY OBJECTIVE: To investigate whether people with occupational exposure to organic solvents have a higher prevalence of obstructive sleep apnea syndrome (OSAS) than the general population and to examine the relationship between snoring and exposure to organic solvents. DESIGN AND PARTICIPANTS: Consecutive patients, aged 30-64 years, referred during a 3-year period to the sleep laboratory at Avesta Hospital, Sweden, because of suspected OSAS made up the patient groups. Following admission, patients underwent a simplified sleep apnea investigation and were divided into two groups, OSAS (n = 320) and snorers (n = 443). A random sample of 296 men and 289 women aged 30-64 years obtained from a register of all country residents maintained by the county tax authority served as referents (controls). Both patients and referents responded to two questionnaires, including questions about occupation, exposure to organic solvents, and other chemical and physical agents. RESULTS: Men with OSAS or snoring and women with snoring had more often been occupationally exposed to organic solvents than the referents, showing an almost twofold increase in risk for those exposed during whole workdays. For men, the risk of OSAS or snoring increased with increasing exposure. CONCLUSION: The result indicates that occupational exposure to organic solvents might cause sleep apnea. A new observation is that even snoring could be caused by exposure to organic solvents. It is important to elucidate whether exposure to organic solvents is a cause of OSAS, because such a finding may have important implications for prevention and treatment of sleep disturbances.     

IgG subclass antibodies to glutamic acid decarboxylase and risk for progression to clinical insulin-dependent diabetes

Pancreatic islet beta cell destruction leading to insulin-dependent diabetes mellitus (IDDM) is believed to be mediated by a T-helper 1 (T(H)1) lymphocyte response to islet antigens. In the mouse, T(H)1 (IL-2, IFN-gamma) and T(H)2 (IL-4, -5, -6, -10) responses are associated with the generation of IgG2a and IgG1 subclasses, respectively. The equivalent human subclasses have not been defined. Because the IgG subclass response to an antigen may be a potentially useful marker of T(H)1/T(H)2 immune balance we measured IgG subclass antibodies to glutamic acid decarboxylase (GAD), a major islet autoantigen in IDDM, in 34 newly-diagnosed IDDM patients and in 28 at-risk, first-degree relatives of people with IDDM. In the newly-diagnosed patients, total IgG antibodies to GAD were detected in 74% (25/34); IgG1 and/or IgG3 were significantly more frequent than IgG4 or IgG4/IgG2 (14/34 versus 5/34, p = 0.01). GAD antibody-negative patients were significantly younger (p = 0.01). In 15 at-risk relatives who had not progressed to clinical diabetes after a median of 4.5 years, 10 had IgG2 and/or IgG4 antibodies compared to only 3/13 progressors (p = 0.02). Total IgG and IgG2 antibodies were higher in non-progressors. Non-progressors were older than progressors (p = 0.01), and relatives with IgG2 and/or IgG4 responses were also older (p = 0.01). These results suggest that IgG subclass antibodies to GAD may contribute to diabetes risk assessment in islet antibody relatives.     

Hymenoptera sting anaphylaxis: detection and clinical significance of individual bee and wasp venoms specific IgE and IgG4 antibodies

In Japan, an average of 37 fatalities per year related to bee or wasp stings were reported during the years 1979-1988. To confirm fatal anaphylaxis serologically, we measured bee or wasp venom specific IgE (sIgE) and IgG4 (sIgG4) antibodies in the sera of 22 patients who visited hospitals with either allergic or anaphylactic reactions after bee or wasp stings by using Enzyme-Linked Immunosorbent Assay. Specific IgE or IgG4 antibodies against Polistes apachus (Paper wasp) and/or a mixture of Polistes annularis, P. exceramans, P. fuscatus, and P. metricus venoms of Polistes genus were detected in 11 patients and the detection frequencies were the highest among positive antibodies against bee or wasp venoms. The severity of allergic reactions was graded from 0-4 according to Mueller. The detection frequencies of sIgE in Mueller grade 0-3 patients were in the range of 33% to 67%, and in grade 4 were 100%. Whereas, the detection frequency of sIgG4 was high (67-100%) in grade 2-4 patients. Especially high levels of sIgE and sIgG4 were detected in patients experiencing the most severe clinical reactions. The detection of venom specific IgE and IgG4 antibodies appears to be useful when determining bee or wasp stings as the cause of fatalities.     

Immunization of LDL receptor-deficient mice with homologous malondialdehyde-modified and native LDL reduces progression of atherosclerosis by mechanisms other than induction of high titers of antibodies to oxidative neoepitopes

We and others previously showed that immunization of rabbits with different forms of oxidized low density lipoprotein (LDL) significantly reduced atherogenesis. We now investigated the effect of continued immunization on atherosclerosis in LDL receptor-deficient (LDLR-/-) mice to determine whether a similar reduction of atherosclerosis occurred in murine models and whether this was due to humoral immune responses, ie, formation of high titers of antibodies to oxidation-specific epitopes. Three groups of LDLR-/- mice were repeatedly immunized with homologous malondialdehyde-modified LDL (MDA-LDL), native LDL, or phosphate-buffered saline (PBS) for 7 weeks. Extensive hypercholesterolemia and accelerated atherogenesis were then induced by feeding a cholesterol-rich diet for 17 weeks, during which immunizations were continued. Binding of immunoglobulin (Ig) M and IgG antibodies, as well as IgG1 and IgG2a isotypes, to several epitopes of oxidized LDL were followed throughout the study. After 24 weeks of intervention, atherosclerosis in the aortic origin was significantly reduced by 46.3% and 36.9% in mice immunized with MDA-LDL and native LDL, respectively, compared with PBS (133 558 and 157 141 versus 248 867 microm2 per section, respectively). However, the humoral immune response to oxidative neoepitopes in the MDA-LDL group was very different from that of the LDL or PBS group. IgG antibody binding to MDA-LDL and other epitopes of oxidized LDL, such as oxidized phospholipid (cardiolipin), oxidized cholesterol, or oxidized cholesteryl linoleate, but not native LDL, increased markedly in mice immunized with MDA-LDL, but not in mice immunized with native LDL or PBS. In the MDA-LDL group, both T helper cell (Th)2-dependent IgG1 antibody and Th1-dependent IgG2a antibody binding to oxidative neoepitopes increased significantly over time. The fact that mice immunized with both MDA-LDL and native LDL had a significant reduction in atherosclerosis, whereas only the MDA-LDL group developed very high titers of antibodies to oxidation-specific epitopes, suggests that the antiatherogenic effect of immunization is not primarily dependent on very high titers of antibodies to oxidation-specific epitopes but is more likely to result from the activation of cellular immune responses.     

Serologic responses of young colostrum fed dairy calves to antigens of Pasteurella haemolytica A1

The potential and limitations of early calfhood vaccination to induce active immunity to Pasteurella haemolytica A1 in conventional colostrum fed calves were investigated. Holstein dairy calves (n = 29) were vaccinated at 2 and 4 weeks of age, or at 6 and 8 weeks of age with a commercial culture supernatant vaccine (Presponse, Langford Inc., Guelph, Ont., Canada), or remained unvaccinated as controls. Serum antibody titres were measured using an indirect bacterial agglutination assay, a leukotoxin neutralization assay, and enzyme immunoassays for antibodies of the IgM, IgG1, and IgG2 isotypes binding purified capsular polysaccharide of P. haemolytica A1. Seroconversion (fourfold or greater increase in serum antibody titre) rates were compared using Fisher's exact test. The effects of passive antibody titres and age on response to vaccination were assessed by linear modelling. Vaccination at 2 and 4 weeks of age was associated with 40%, and 0% of calves seroconverting on the basis of agglutinating antibody titres, and leukotoxin neutralizing titres respectively, and 50%, 0%, and 0% seroconverting on the basis of IgM, IgG1 and IgG2 antibodies to capsular polysaccharide, respectively. Agglutinating antibody responses were not related to prevaccination antibody titres, or to age at vaccination. Higher responses (p = 0.08) to leukotoxin were observed in older calves (after taking differences in prevaccination titres into account). Statistical analyses of responses to capsular polysaccharide among calves with comparable prevaccination IgG1 antibody titres revealed significantly higher IgM, IgG1 and IgG2 responses in older calves. Rising titres of IgM antibodies in nonvaccinated calves after 5 weeks of age suggest natural exposure to P. haemolytica A1 or antigens which result in serologic cross-reactions as a means of priming immune responses.     

Clinical factors relating to the presence of serum anti-GM1 and GD1b antibodies in demyelinating neuropathy--study using a multivariate analysis

We studied clinical factors relating to the presence of serum anti-GM1 and GD1b antibodies in patients with demyelinating neuropathy using a multivariate analysis. Sera were obtained from 46 patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and 33 with Guillain-Barré syndrome (GBS) and kept frozen at -20 degrees C until use. Anti-GM1 and GD1b IgM and IgG antibodies were measured by ELISA at serum dilution of 1:100 and considered to be positive when those values were more than the cut off values determined by means and standard deviations in 35 normal controls. Age, sex, duration, prodromal disease, neurological findings, concentration of CSF protein, nerve conduction, treatment, and outcome were investigated in all patients retrospectively. Multivariate logistic models using all those characteristics were used to clarify the clinical factors relating to the presence of anti-GM1 and GD1b antibodies. In CIDP, anti-GM1 antibodies associated with or without anti-GD1b antibodies were frequently seen in patients with motor dominant neuropathy than those with sensory dominant neuropathy (P = 0.007, odds ratio = 11.6). There was significant difference in anti-GM1 IgM antibodies (P = 0.003, odds ratio = 22.2), but no difference in IgG antibodies. Anti-GM1 antibodies were observed 5 (IgM, 5; IgG, 2) of 7 patients with pure motor neuropathy, 9 (IgM, 8; IgG, 4) of 17 with motor dominant neuropathy, 5 (IgM, 2; IgG, 3) of 16 with sensori-motor neuropathy, and none of 6 with sensory dominant neuropathy.(ABSTRACT TRUNCATED AT 250 WORDS)