Use of radiolabelled monoclonal anti-CEA antibodies for the detection of human carcinomas by external photoscanning and tomoscintigraphy

Paul Ehrlich's inspired concept of 'magic bullets' for the cure of diseases has been revitalized by recent advances in immunology1. In particular, the development of cell fusion technology allowing the production of monoclonal antibodies (Mabs) with exquisite specificities2 triggered new hopes that we may now have the perfect carrier molecules with which to deliver cytotoxic drugs3 or toxins4 to the hidden cancer cells. This article reviews data on one aspect of the magic bullet concept, the use of radiolabelled antibodies as tracers for tumour localization. It will also discuss the very recent clinical use of 131I-labelled Mabs against carcinoembryonic antigen (CEA)5 to detect carcinoma either by conventional external photoscanning or by single photon emission computerized tomography (SPELT). This alliance of the most modern tools from immunology (Mabs) and nuclear medicine (SPELT) appears promising as a way to improve the sensitivity of 'immunoscintigraphy'. However, this approach is not yet ready, for widespread clinical use.

Improving the chance of cure of follicular lymphoma by combining immunotherapy and radioimmunotherapy based on anti-CD20 antibodies?

Right ventricular and left ventricular systolic time intervals (RVSTIs and LVSTIs) were measured in normal term and preterm infants from 1 hour to 90 days of life. LVSTIs in both term and preterm infants were similar in the first five days of life. The ratio of left pre-ejection period (LPEP) to left ventricular ejection time (LVET) was lower in preterm infants older than age 5 days. Estimated gestational age had no influence on LVSTI. The ratio of right pre-ejection period (RPEP) to right ventricular ejection time (RVET) was lower in preterm infants (0.32) than in term newborns (0.37). The preterm RPEP/RVET ratio decreased with age, but at a slower rate than in term babies. This was consistent with the lower pulmonary vascular resistance present in preterm infants.

The efficacy and safety of a third anti-TNF monoclonal antibody in Crohn's disease after failure of two other anti-TNF antibodies.

BACKGROUND: Adalimumab (ADA) and certolizumab pegol (CZP) have demonstrated efficacy in Crohn's disease (CD) patients previously treated with infliximab (IFX). AIM: To assess the efficacy and tolerability of a third anti-TNF in CD after failure of and/or intolerance to two different anti-TNF antibodies. METHODS: Crohn's disease patients who received ADA or CZP after loss of response and/or intolerance to two anti-TNF agent were included in this retrospective study. Data were collected using a standardized questionnaire. Clinical response, duration, safety and reasons for discontinuation were assessed. RESULTS: Sixty-seven patients treated with CZP (n = 40) or ADA (n = 27) were included. A clinical response was observed in 41 (61%) at week 6 and 34 patients (51%) at week 20. The probability of remaining under treatment at 3 months, 6 months and 9 months was 68%, 60% and 45%, respectively. At the end of follow-up, the third anti-TNF had been stopped in 36 patients for intolerance (n = 13), or failure (n = 23). Two deaths were observed. CONCLUSIONS: The treatment with a third anti-TNF (CZP or ADA) agent of CD patients, who have experienced loss of response and/or intolerance to two anti-TNF antibodies, has favourable short-term and long-term efficacy. It is an option to be considered in patients with no other therapeutic options.

Prevalence and significance of anti-HILA antibodies after liver transplantation : P236

Background: The pathogenic role of anti-HLA antibodies (AHA) after kidney transplantation is well established. However, its significance after liver transplantation remains unclear. The aim of our study was to determine the prevalence and significance of AHA after liver transplantation. Methods: Between January 2007 and November 2007, all liver transplant recipients who were greater than 6 months posttransplantation and followed regularly at our transplant outpatient clinic (n = 95) were screened for AHA. All clinical and electronic records were reviewed. Serum samples were tested using multiplex technology (Luminex). A liver biopsy had been performed in 55 out of the 95 patients based on clinical grounds but no routine protocol biopsies were performed. Immunosuppression was calcineurin inhibitor-based in 90 patients, sirolimus-based in 4 patients and one patient had no anti-rejection therapy (operationally tolerant recipient). Results: The mean time from transplantation to study was 85 months (range 6-248 months). Overall, AHA were found in 23/95 (24.2%) of patients (5 had anti-class I alone, 13 anti-class II alone, and 4 had both anti-class I and II). However, only 4/95 patients (4.2%) had donor-specific antibodies (DSA) (one anti-class I and 3 anti-class II). Twenty-one out of 95 patients (22.1%) had a history of past or current biopsy-proven or radiological biliary complications (chronic rejection, ischemic cholangitis, ischemic type biliary lesions or biliary anastomosis stricture). Among patients with AHA, 4/23 (17,4%) had biliary complications, while it was 17/72 (23.6%) in patients without AHA (NS). Among patients with DSA, 3/4 (75%) had biliary complications (two with biopsy-proven chronic rejection in association with biliary strictures and one with ischemic cholangitis following hepatic artery thrombosis), versus 1/19 (5.3%) patients with AHA but no DSA (p = 0.009), versus 16/72 (22.2%) patients without AHA (p = 0.046). In patients with DSA, immunosuppression was not different than in patients without DSA. Conclusions: We found a 24% AHA prevalence. The presence of DSA, but not of AHA, was significantly associated with an increased incidence of biliary complications including chronic liver allograft rejection. The exact mechanisms and possible causal relationship linking DSA to biliary complications remain to be studied. Larger prospective trials are thus needed to further define the role of AHA and in particular of DSA after liver transplantation.

Anti-MPER antibodies with heterogeneous neutralization capacity are detectable in most untreated HIV-1 infected individuals

Background The MPER region of the HIV-1 envelope glycoprotein gp41 is targeted by broadly neutralizing antibodies. However, the localization of this epitope in a hydrophobic environment seems to hamper the elicitation of these antibodies in HIV infected individuals. We have quantified and characterized anti-MPER antibodies by ELISA and by flow cytometry using a collection of mini gp41-derived proteins expressed on the surface of 293T cells. Longitudinal plasma samples from 35 HIV-1 infected individuals were assayed for MPER recognition and MPER-dependent neutralizing capacity using HIV-2 viruses engrafted with HIV-1 MPER sequences. Results Miniproteins devoid of the cysteine loop of gp41 exposed the MPER on 293T cell membrane. Anti-MPER antibodies were identified in most individuals and were stable when analyzed in longitudinal samples. The magnitude of the responses was strongly correlated with the global response to the HIV-1 envelope glycoprotein, suggesting no specific limitation for anti-MPER antibodies. Peptide mapping showed poor recognition of the C-terminal MPER moiety and a wide presence of antibodies against the 2F5 epitope. However, antibody titers failed to correlate with 2F5-blocking activity and, more importantly, with the specific neutralization of HIV-2 chimeric viruses bearing the HIV-1 MPER sequence; suggesting a strong functional heterogeneity in anti-MPER humoral responses. Conclusions Anti-MPER antibodies can be detected in the vast majority of HIV-1 infected individuals and are generated in the context of the global anti-Env response. However, the neutralizing capacity is heterogeneous suggesting that eliciting neutralizing anti-MPER antibodies by immunization might require refinement of immunogens to skip nonneutralizing responses.

Evaluation of a new serological test for the detection of anti-Coxiella and anti-Rickettsia antibodies.

Coxiella burnetii and members of the genus Rickettsia are obligate intracellular bacteria. Since cultivation of these organisms requires dedicated techniques, their diagnosis usually relies on serological or molecular biology methods. Immunofluorescence is considered the gold standard to detect antibody-reactivity towards these organisms. Here, we assessed the performance of a new automated epifluorescence immunoassay (InoDiag) to detect IgM and IgG against C. burnetii, Rickettsia typhi and Rickettsia conorii. Samples were tested with the InoDiag assay. A total of 213 sera were tested, of which 63 samples from Q fever, 20 from spotted fever rickettsiosis, 6 from murine typhus and 124 controls. InoDiag results were compared to micro-immunofluorescence. For acute Q fever, the sensitivity of phase 2 IgG was only of 30% with a cutoff of 1 arbitrary unit (AU). In patients with acute Q fever with positive IF IgM, sensitivity reached 83% with the same cutoff. Sensitivity for chronic Q fever was 100% whereas sensitivity for past Q fever was 65%. Sensitivity for spotted Mediterranean fever and murine typhus were 91% and 100%, respectively. Both assays exhibited a good specificity in control groups, ranging from 79% in sera from patients with unrelated diseases or EBV positivity to 100% in sera from healthy patients. In conclusion, the InoDiag assay exhibits an excellent performance for the diagnosis of chronic Q fever but a very low IgG sensitivity for acute Q fever likely due to low reactivity of phase 2 antigens present on the glass slide. This defect is partially compensated by the detection of IgM. Because it exhibits a good negative predictive value, the InoDiag assay is valuable to rule out a chronic Q fever. For the diagnosis of rickettsial diseases, the sensitivity of the InoDiag method is similar to conventional immunofluorescence.

Reactivity of anti-thyroid antibodies to thyroglobulin tryptic fragments: comparison of autoimmune and non-autoimmune thyroid diseases

Studies concerning the antigenicity of thyroglobulin fragments allow the characterization of the epitopes but do not consider the role of heavier antigenic fragments that could result in vivo from the action of endoproteases. Here we assess the relative importance of the fragments obtained from thyroglobulin by limited proteolysis with trypsin and compare by immunoblotting their reactivity to serum from patients with autoimmune (Graves' disease and Hashimoto's thyroiditis) and non-autoimmune (subacute thyroiditis) disease. The results showed no difference in frequency of recognition of any peptide by sera from patients with autoimmune thyroiditis. In contrast, sera from patients with subacute thyroiditis reacted more frequently with a peptide of 80 kDa. These results suggest the presence of antibody subpopulations directed at fragments produced in vivo by enzymatic cleavage of thyroglobulin. This fragment and antibodies to it may represent markers for subacute thyroiditis.

Anti-leishmania antibodies in cerebrospinal fluid from dogs with visceral leishmaniasis

Visceral leishmaniasis in Brazil is caused by Leishmania (Leishmania) chagasi and the dog is its most important reservoir. The clinical features in dogs include loss of weight, lymphadenopathy, renal failure, skin lesions, fever, hypergammaglobulinemia, hepatosplenomegaly, anemia, and, rarely, neurological symptoms. Most infected animals develop active disease, characterized by high anti-leishmania antibody titers and depressed lymphoproliferative ability. Antibody production is not primarily important for protection but might be involved in the pathogenesis of tissue lesions. An ELISA test was used to determine if there is an association between neurological symptoms and the presence of anti-L. chagasi antibodies in cerebrospinal fluid (CSF). Thirty serum and CSF samples from symptomatic mixed breed dogs (three with neurological symptoms) from a region of high incidence of visceral leishmaniasis in Brazil were examined for antibody using total parasite antigen and anti-dog IgG peroxidase conjugate. A high level of L. chagasi antibodies was observed in sera (mean absorbance ± SD, 1.939 ± 0.405; negative control, N = 20, 0.154 ± 0.074) and CSF (1.571 ± 0.532; negative control, N = 10, 0.0195 ± 0.040) from all animals studied. This observation suggests that L. chagasi can cause breakdown of filtration barriers and the transfer of antibodies and antigens from the blood to the CSF compartment. No correlation was observed between antibody titer in CSF and neurological symptoms.

Prevalence of hepatitis C virus (HCV) infection and HCV genotypes of hemodialysis patients in Salvador, Northeastern Brazil

Hepatitis C virus (HCV) infection has been identified as the major cause of chronic liver disease among patients on chronic hemodialysis (HD), despite the important reduction in risks obtained by testing candidate blood donors for anti-HCV antibodies and the use of recombinant erythropoietin to treat anemia. A cross-sectional study was performed to estimate the prevalence of HCV infection and genotypes among HD patients in Salvador, Northeastern Brazil. Anti-HCV seroprevalence was determined by ELISA in 1243 HD patients from all ten different dialysis centers of the city. HCV infection was confirmed by RT-PCR and genotyping was performed by restriction fragment length polymorphism. Anti-HCV seroprevalence among HD patients was 10.5% (95% CI: 8.8-12.3) (Murex anti-HCV, Abbott Murex, Chicago, IL, USA). Blood samples for qualitative HCV detection and genotyping were collected from 125/130 seropositive HD patients (96.2%). HCV-RNA was detected in 92/125 (73.6%) of the anti-HCV-positive patients. HCV genotype 1 (77.9%) was the most prevalent, followed by genotype 3 (10.5%) and genotype 2 (4.6%). Mixed infections of genotypes 1 and 3 were found in 7.0% of the total number of patients. The present results indicate a significant decrease in anti-HCV prevalence from 23.8% detected in a study carried out in 1994 to 10.5% in the present study. The HCV genotype distribution was closely similar to that observed in other hemodialysis populations in Brazil, in local candidate blood donors and in other groups at risk of transfusion-transmitted infection.

Recombinant anti-EspA antibodies block Escherichia coli O157:H7-induced attaching and effacing lesions in vitro

Intimin and EspA proteins are virulence factors expressed by attaching and effacing Escherichia coli (AEEC) such as enteropathogenic and enterohaemorrhagic E. coli. The EspA protein makes up a filament structure forming part of the type III secretion system (TTSS) that delivers effector proteins to the host epithelial cell. Bacterial surface displayed intimin interacts with translocated intimin receptor in the host cell membrane leading to intimate attachment of the bacterium and subsequent attaching and effacing lesions. Here, we have assessed the use of recombinant monoclonal antibodies against E. coli O157:147 EspA and intimin for the disruption of AEEC interaction with the host cell. Anti-gamma intimin antibodies did not reduce either adhesion of E. coli O157:H7 to host cell mono-layers or subsequent host cell actin rearrangement. Anti-EspA antibodies similarly had no effect on bacterial adhesion however they had a marked effect upon E. coli O157:H7-induced host cell actin rearrangement, where both monoclonal and polyclonal antibodies completely blocked cytoskeletal changes within the host cell. Furthermore, these anti-EspA antibodies were shown to reduce actin rearrangement induced by some but not all other AEEC serotypes tested. Both polyclonal and monoclonal antibodies could be used to label E. coli O157 EspA filaments and these immunoreagents did not inhibit the formation of such filaments. This is the first report of monoclonal antibodies to EspA capable of disrupting the TTSS function of E. coli O157:H7. (c) 2005 Elsevier SAS. All rights reserved.

Dystrophin analysis using a panel of anti-dystrophin antibodies in Duchenne and Becker muscular dystrophy.

Dystrophin, the protein product of the Duchenne muscular dystrophy (DMD) gene, was studied in 19 patients with Xp21 disorders and in 25 individuals with non-Xp21 muscular dystrophy. Antibodies raised to seven different regions spanning most of the protein were used for immunocytochemistry. In all patients specific dystrophin staining anomalies were detected and correlated with clinical severity and also gene deletion. In patients with Becker muscular dystrophy (BMD) the anomalies detected ranged from inter- and intra-fibre variation in labelling intensity with the same antibody or several antibodies to general reduction in staining and discontinuous staining. In vitro evidence of abnormal dystrophin breakdown was observed reanalysing the muscle of patients, with BMD and not that of non-Xp21 dystrophies, after it has been stored for several months. A number of patients with DMD showed some staining but this did not represent a diagnostic problem. Based on the data presented, it was concluded that immunocytochemistry is a powerful technique in the prognostic diagnosis of Xp21 muscular dystrophies.

Volsurf Descriptors to Analyse Anti-HCV and Cytotoxic Activities of Sesquiterpene Lactones from Asteraceae Family

Various significant anti-HCV and cytotoxic sesquiterpene lactones (SLs) have been characterized. In this work, the chemometric tool Principal Component Analysis (PCA) was applied to two sets of SLs and the variance of the biological activity was explored. The first principal component accounts for as much of the variability in the data as possible, and each succeeding component accounts for as much of the remaining variability as possible. The calculations were performed using VolSurf program. For anti-HCV activity, PC1 (First Principal Component) explained 30.3% and PC2 (Second Principal Component) explained 26.5% of matrix total variance, while for cytotoxic activity, PC1 explained 30.9% and PC2 explained 15.6% of the total variance. The formalism employed generated good exploratory and predictive results and we identified some structural features, for both sets, important to the suitable biological activity and pharmacokinetic profile.