Cross-reactive idiotopes among anti-foot and mouth disease virus neutralizing antibodies.

Foot and mouth disease virus (FMDV) viral protein 1 is the only one of the four viral proteins (VP) that induces neutralizing antibodies as an isolated protein. A 32 amino acid (AA) residue (32dimer) of FMDV subtype A12 Lp ab VP1 (AA 137-168) was immunogenic against the A12 subtype. Three antibody populations each recognizing different epitopes on 32dimer were isolated by affinity chromatography (AFC) from the serum of a steer which had been immunized with the 32dimer. The 32dimer contains an AA sequence that is recognized by a protective paratope carried on a murine monoclonal antibody (mAb) (7SF-3.H3.1). Polyclonal anti-7SF-3 idiotype antibodies specifically inhibited the binding activity of one of these anti-32dimer antibody populations suggesting the existence of cross-reactive paratopic-related idiotopes between mAb 7SF-3 and antibodies elicited by the 32dimer. These anti-idiotypic antibodies were used in AFC to purify antibodies from the anti-32dimer serum. The purified antibody population has characteristics that resemble those of the mAb 7SF-3, i.e. its reactivity with FMDV A subtypes in ELISA, radioimmunoassay (RIA), mouse neutralization and its lack of reactivity with a mAb 7SF-3 neutralizing escape virus variant. Furthermore, these antibodies were specifically inhibited by either anti-mAb 7SF-3 idiotypic antibodies or peptides containing the mAb 7SF-3 epitope. Using the same experimental approach, mAb 7SF-3 idiotope-bearing antibodies were shown to be present in serum from bovine and swine convalescent from FMDV A12 Lp ab infection. Thus, the highly immunogenic area between residues 137 and 168 of FMDV VP1 elicited a cross-reactive neutralizing idiotope response conserved amongst several animal species.     

Characterization of anti-idiotypic antibodies generated against foot-and-mouth disease virus neutralizing monoclonal antibodies

A series of seven neutralizing monoclonal antibodies (nMAbs) against type A12 foot-and-mouth disease virus (FMDV) was used to induce polyclonal anti-idiotypic antibodies (anti-ids) in rabbits. The anti-ids were semi-purified through isotype affinity columns and assayed by solid-phase radioimmunoassay for cross-reactivity. nMAbs which map to the same epitope on the virion appear to contain a common idiotype, and the corresponding anti-ids competitively inhibited the virus-nMAb reaction. Using a modified ELISA assay, it was possible to demonstrate binding of purified anti-ids to FMDV susceptible tissue culture cells. Such antibodies however, did not interfere with the binding of virus to cells, and the binding of anti-ids to FMDV receptor-negative cells could also be demonstrated. Mice were inoculated with purified anti-ids, and two elicited anti-viral antibodies, although these antibodies were non-neutralizing. Thus anti-ids to anti-FMDV nMAbs failed to react with cellular receptors for the virus, but were able to induce anti-viral antibody and thus should be examined as an alternative vaccine strategy for this virus.     

New syngeneic inflammatory‐related lung cancer metastatic model harboring double KRAS/WWOX alterations

New mouse models with specific drivers of genetic alterations are needed for preclinical studies. Herein, we created and characterized at the genetic level a new syngeneic model for lung cancer and metastasis in Balb‐c mice. Tumor cell lines were obtained from a silica‐mediated airway chronic inflammation that promotes tumorigenesis when combined with low doses of N‐nitrosodimethylamine, a tobacco smoke carcinogen. Orthotopic transplantation of these cells induced lung adenocarcinomas, and their intracardiac injection led to prominent colonization of various organs (bone, lung, liver and brain). Driver gene alterations included a mutation in the codon 12 of KRAS (G–A transition), accompanied by a homozygous deletion of the WW domain‐containing oxidoreductase (WWOX) gene. The mutant form of WWOX lacked exons 5–8 and displayed reduced protein expression level and activity. WWOX gene restoration decreased the in vitro and in vivo tumorigenicity, confirming the tumor suppressor function of this gene in this particular model. Interestingly, we found that cells displayed remarkable sphere formation ability with expression of specific lung cancer stem cell markers. Study of non‐small‐cell lung cancer patient cohorts demonstrated a deletion of WWOX in 30% of cases, with significant reduction in protein levels as compared to normal tissues. Overall, our new syngeneic mouse model provides a most valuable tool to study lung cancer metastasis in balb‐c mice background and highlights the importance of WWOX deletion in lung carcinogenesis.     

Pulmonary hypertension in systemic lupus erythematosus: prevalence,predictors and diagnostic strategy

ObjectivesTo investigate the prevalence and predictors of pulmonary hypertension (PH) in patients with systemic lupus erythematosus (SLE) and to validate a diagnostic strategy.Methods245 patients with SLE entered a screening program. Possible PH was defined as two consecutive systolic pulmonary arterial pressure (PAP) values ≥ 40 mm Hg by echocardiography. The subsequent diagnostic procedure, including right heart catheterization if needed, confirmed or excluded the diagnosis of PH secondary to cardiopulmonary disease or SLE-related pulmonary arterial hypertension (PAH). Independent predictors of PH were identified by multivariant multiple linear or logistic regression models. The sensitivity (S), specificity (SP), positive (PPV) and negative predictive values (NPV) were calculated for different screening cutoff values.Results88% patients were women. The mean (SD) age at the time of enrolment was 45 (16) years. 12 cases of PH were detected, all secondary, with a resulting prevalence of 5%. Two consecutive echocardiographic PAP measurements ≥ 40 mm Hg performed best as the cutoff point for screening (S 100%, SP 97%, PPV 70, NPV 100), as compared with single PAP measurements ≥ 30 mm Hg or ≥ 40 mm Hg The age at the time of enrolment was the only variable independently associated with PAP values (p = 0.0001), with the SLICC damage index score showing a borderline association (p = 0.08). Only the age at the time of enrolment showed an independent association with PH (OR 1.10, 95% CI 1.06–1.17).ConclusionWe found a low prevalence of PH. Screening echocardiograms in asymptomatic lupus patients are thus not recommended. Two consecutive PAP values ≥ 40 mm Hg by echocardiogram is the best screening cutoff for starting investigations in SLE patients with suspected PH.