Generation and characterization of avian IgY antibodies for detecting beta-casein A1 in bovine milk

Beta-casein is a primary milk protein that constitutes approximately 30% of the casein in bovine milk, with the two most common types in cattle being A1 and A2. The A2 protein differs from the A1 version due to a mutation in the codon at position 67, resulting in a histidine to proline substitution. However, the bioactive peptide, beta-casomorphine-7 (BCM7), which originates from partial proteolysis of the A1 variant, has been linked to several gastrointestinal disorders in humans. Production of A1 beta casein-free products is increasing demand in the milk market, worldwide. This study generated and characterized a polyclonal IgY antibody that specifically recognizes the A1 beta-casein protein present in cow's milk. A commercially available IgY anti-A1 antibody was used as a positive control, and the sensitivity and specificity of both the commercial and produced anti-A1 antibodies were evaluated. The results showed 100% sensitivity and specificity of 100% of the commercial IgY anti-A1. The in-house produced anti-A1 antibody demonstrated a sensitivity of 95.2% and a specificity of 100%, indicating its potential as a reliable and cost effective tool for detecting A1 beta-casein protein in milk samples.

Trends of respiratory virus detection in point-of-care testing: A review

In resource-limited conditions such as the COVID-19 pandemic, on-site detection of diseases using the Point-of-care testing (POCT) technique is becoming a key factor in overcoming crises and saving lives. For practical POCT in the field, affordable, sensitive, and rapid medical testing should be performed on simple and portable platforms, instead of laboratory facilities. In this review, we introduce recent approaches to the detection of respiratory virus targets, analysis trends, and prospects. Respiratory viruses occur everywhere and are one of the most common and widely spreading infectious diseases in the human global society. Seasonal influenza, avian influenza, coronavirus, and COVID-19 are examples of such diseases. On-site detection and POCT for respiratory viruses are state-of-the-art technologies in this field and are commercially valuable global healthcare topics. Cutting-edge POCT techniques have focused on the detection of respiratory viruses for early diagnosis, prevention, and monitoring to protect against the spread of COVID-19. In particular, we highlight the application of sensing techniques to each platform to reveal the challenges of the development stage. Recent POCT approaches have been summarized in terms of principle, sensitivity, analysis time, and convenience for field applications. Based on the analysis of current states, we also suggest the remaining challenges and prospects for the use of the POCT technique for respiratory virus detection to improve our protection ability and prevent the next pandemic.

A cohort study reveals different dynamics of SARS-CoV-2-specific antibody formation after Comirnaty and Vaxzevria vaccination

The Coronavirus (COVID-19) Disease Pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has affected millions of people worldwide, prompting a collective effort from the global scientific community to develop a vaccine against it. This study purports to investigate the influence of factors such as sex, age, type of vaccination (Comirnaty, BNT162b2, Pfizer Inc. or Vaxzevria, ChAdOx1-S, Oxford/AstraZeneca), and time since vaccine administration on the process of antibody production. Both of them are based on the introduction of SARS-CoV-2 spike protein (S protein) to the body using different mechanisms (mRNA and recombinant adenovirus, respectively). S protein is responsible for host cell attachment and penetration via its receptor-binding domain (RBD domain). The level of anti-RBD IgG antibodies was tested with an ELISA-based immunodiagnostic assay in serum samples from a total of 1395 patients at 3 time points: before vaccination, after the first dose, and after the second dose. Our novel statistical model, the Generalized Additive Model, revealed variability in antibody production dynamics for both vaccines. Interestingly, no discernible variation in antibody levels between men and women was found. A nonlinear relationship between age and antibody production was observed, characterized by decreased antibody levels for people up to 30 and over 60 years of age, with a lack of correlation in the middle age range. Collectively, our findings further the understanding of the mechanism driving vaccine-induced immunity. Additionally, we propose the Generalized Additive Model as a standardized way of presenting data in similar research.

Heartworm (Dirofilaria immitis) in carnivores kept in zoos in Texas, USA: risk perception, practices, and antigen detection

BACKGROUND

Dirofilaria immitis is the causative agent of heartworm disease in wild and domestic canids, felids, and mustelids. Recent studies demonstrate that additional families in the order Carnivora are also susceptible to infection. Therefore, the objectives of this study were to (1) better understand current practices surrounding heartworm prevention and diagnostics in zoological facilities located in the state of Texas, USA, and (2) assess archival serum samples of carnivores kept in these facilities for the presence D. immitis antigen and/or antibody.

METHODS

A questionnaire was completed by veterinarians or veterinary technicians representing 10 zoological facilities across Texas. This questionnaire was designed at the taxonomic family level, encompassing the 12 terrestrial carnivore families Ailuridae, Canidae, Eupleridae, Felidae, Herpestidae, Hyaenidae, Mephitidae, Mustelidae, Prionodontidae, Procyonidae, Ursidae, and Viverridae. The second objective was achieved with the use of archival serum samples made available by six zoo facilities.

RESULTS

Risk perception varied across facilities for every family, including among species belonging to Canidae. All facilities used monthly heartworm prevention in canids and felids, with more variation existing in the other families. The use of diagnostic testing and type and route of administration of preventive varied by facility, with oral ivermectin the most commonly used preventive. A total of 217 archival serum samples, belonging to 211 individual animals encompassing 11 families and 39 species, were tested with a commercial heartworm antigen ELISA test, pre- and post-immune-complex dissociation. A subset of samples was also assessed for the presence of feline anti-heartworm antibodies using a commercial ELISA test. Two animals, both of which were Asian small-clawed otters from the same facility, had antigen detected (0.95%).

CONCLUSIONS

This study demonstrates that while the zoo veterinary community is aware of the risk and health impact of heartworm disease in canids and felids, there is still a great deal of uncertainty regarding the risks and ideal strategies for prevention in other carnivore families. The low proportion of antigen detection may serve as a baseline for future prevalence studies across the southern United States, where there is an emerging concern of macrocyclic lactone resistance in heartworm.

Characterizing and applying immunoglobulins in snakebite diagnostics: A simple and rapid venom detection assay for four medically important snake species in Southeast Asia

Snakebite envenoming is a medical emergency requiring urgent and specific treatment. Unfortunately, snakebite diagnostics are scarce, time-consuming and lacking specificity. Hence, this study aimed to develop a simple, quick and specific snakebite diagnostic assay using animal antibodies. Anti-venom horse immunoglobulin G (IgG) and chicken immunoglobulin Y (IgY) were produced against the venoms of four major medically important snake species in Southeast Asia, i.e., the Monocled Cobra (Naja kaouthia), Malayan Krait (Bungarus candidus), Malayan Pit Viper (Calloselasma rhodostoma), and White-lipped Green Pit Viper (Trimeresurus albolabris). Different capture:detection configurations of double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) were constructed using both immunoglobulins, and the horse IgG:IgG-HRP configuration was found to be most selective and sensitive in detecting the corresponding venoms. The method was further streamlined to develop a rapid immunodetection assay, which is able to produce a visual color change within 30 min for discrimination between different snake species. The study shows it is feasible to develop a simple, quick and specific immunodiagnostic assay using horse IgG, which can be derived directly from antisera prepared for antivenom production. The proof-of-concept indicates it is a sustainable and affordable approach in keeping with on-going antivenom manufacturing activities for specific species in the region.

Detection of Dirofilaria immitis via integrated serological and molecular analyses in coyotes from Texas, United States

Wild canids serve as reservoir for various vector-borne pathogens of veterinary and medical importance, including the canine heartworm, Dirofilaria immitis. In North and Central America, coyotes (Canis latrans) may be a relevant reservoir host for heartworm transmission. The objective of this study was to determine the occurrence of D. immitis in coyotes across Texas using integrated antigen detection test and molecular assays. Matching whole blood and serum samples were collected from 122 coyotes from different locations across the state of Texas, United States, encompassing nine counties. Collections occurred from February to April 2016, and December 2016. Samples were assessed serologically using a commercial microtiter plate ELISA (DiroCHEK®), and molecularly by conventional PCR targeting the cytochrome oxidase c subunit 1 (cox1) and NADH dehydrogenase subunit 5 (nad5) of the mitochondrial DNA, and via a TaqMan© probe-based real-time PCR protocol, also targeting a fragment of the cox1 gene. Overall, 12 (9.83%) samples tested positive when serological and molecular results were combined. Seven of 122 samples (5.73%) were antigen-positive, 8 (6.55%) were qPCR-positive, and 4 (3.27%) were positive using conventional PCR. Of 12 positive samples, 4 tested antigen-positive by DiroCHEK® but were negative in all molecular tests, another 4 tested positive by at least one of the molecular assays but tested negative by DiroCHEK®, and 3 samples tested positive by both antigen test and at least one of the molecular assays. Two samples (16.67%) tested positive on both the antigen test and both conventional PCR and qPCR. Our study confirmed the presence of D. immitis infection in coyotes from southern and northern Texas. The combination of serologic and molecular diagnostic tests was proven synergistic for the identification of D. immitis infections, including occult dirofilariosis, and revealed a more accurate picture of heartworm occurrence in the sampled coyotes.

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Coyotes are an important wild reservoir for Dirofilaria immitis in North America.

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We collected 121 matching blood and serum samples of coyotes from Texas, USA.

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Twelve samples (9.92%) tested positive combining serology and molecular tests data.

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Probe-based qPCR was superior than conventional PCR for heartworm diagnosis.

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Combined DiroCHEK® and qPCR data showed a higher prevalence than each test alone.

Diagnosis failure of bovine leukosis: serology variation during the peripartum period

This study demonstrates the influence of pregnancy on serum diagnosis of enzootic bovine leukosis (EBL), emphasizing the importance of routine testing to maintain herd health. For this, 143 pregnant cows were sampled in duplicate (30 days before and 15 days after calving). For EBL diagnosis, samples were submitted to agar gel immunodiffusion testing (AGID). Different results were observed before and after delivery in seventy-six serum samples (53.15%), indicating variations in the levels of serum globulins in the blood during the peripartum period. Therefore, using a single sample for serological diagnosis during the birth season might not represent the correct infection status of animal health due to physiological variations in antibody concentrations.

Expression and characterization of a recombinant broadly-reactive monoclonal antibody against group 1 and 2 influenza viruses

Production of broadly-reactive antibodies is critical for universal immunodiagnosis of rapidly-evolving influenza viruses. Most monoclonal antibodies (mAbs) are generated in mice using the hybridoma technology which involves labor- and time-consuming screening and low yield issues. In this study, a recombinant antibody based on a broadly-reactive mAb against the hemagglutinin (HA) stalk of H7N9 avian influenza virus was expressed in CHO cells and its biological characteristics, cross-reactivity and epitope recognition were identified. The variable genes of the parental antibody were amplified and cloned into the antibody-expressing plasmids containing the constant genes of murine IgG1. The recombinant antibody was expressed in high yield and purity in CHO cells and showed similar features to the parental antibody, including negative hemagglutination inhibition activity against H7N9 virus and high binding activity with the H7N9 HA protein. Notably, the recombinant antibody exhibited a broad reactivity with different influenza subtypes belonging to group 1 and group 2, which was associated with its recognition of a highly-conserved epitope in the stalk, as observed for the parental antibody. Our results suggest that cell-based antibody expression system can be utilized as an important alternative to the hybridoma technology for antibody production for influenza virus diagnostics.

Molecular detection of Sarcocystis neurona in cerebrospinal fluid from 210 horses with suspected neurologic disease

An ante-mortem diagnosis of equine protozoal myeloencephalitis (EPM) is presently based on clinical presentation, immunodiagnostics performed on serum and cerebrospinal fluid (CSF), and ruling out other neurological disorders. Molecular techniques introduce a novel and promising approach for the detection of protozoal agents in CSF. Hypothesizing that real-time PCR (rtPCR) can be a useful complement to EPM diagnostics, 210 CSF samples from horses suspected of neurological disease with EPM included as a differential diagnosis were tested using rtPCR to detect Sarcocystis neurona DNA and immunodiagnostics targeting antibodies against the same pathogen, performed on serum and CSF samples. Molecular and immunological results were compared with respect to origin of the horse, time of the year, signalment, clinical signs and treatment history. Twenty-five horses tested positive in CSF for S. neurona by rtPCR only, while 30 horses had intrathecally-derived antibodies to S. neurona only (serum to CSF ratio ≤ 64 by indirect fluorescent antibody test - IFAT), and 13 horses tested rtPCR-positive in CSF with evidence of intrathecally-derived antibodies to S. neurona. Previous treatment for EPM was the only variable presenting statistical difference between the two testing modalities, highlighting that animals with history of anti-protozoal treatment were more likely to test positive solely in IFAT, while horses without treatment were more likely to test positive by rtPCR only. The results support the use of molecular diagnosis for EPM caused by S. neurona as a complement to immunodiagnostics. The use of rtPCR in CSF for the detection of S. neurona may improve the diagnostic work-up of neurologic disease suspected horses, especially in animals without previous anti-protozoal treatment.

The Intervening Removable Affinity Tag (iRAT) System for the Production of Recombinant Antibody Fragments

Fv and Fab antibody fragments are versatile co-crystallization partners that aid in the structural determination of otherwise "uncrystallizable" proteins, including human/mammalian membrane proteins. Accessible methods for the rapid and reliable production of recombinant antibody fragments have been long sought. In this chapter, we describe the concept and protocols of the intervening removable affinity tag (iRAT) system for the efficient production of Fv and Fab fragments in milligram quantities, which are sufficient for structural studies. As an extension of the iRAT system, we also provide a new method for the creation of genetically encoded fluorescent Fab fragments, which are potentially useful as molecular devices in various basic biomedical and clinical procedures, such as immunofluorescence cytometry, bioimaging, and immunodiagnosis.

Diagnostic Methods for Detecting Internal Parasites of Livestock

Internal parasites are a major concern in livestock production because they can impact the health and well-being of animals clinically and subclinically, and ultimately cause significant production loss. Among these internal parasites are nematodes, tapeworms, flukes, and coccidian protozoans. This review focuses on the diagnostic tests that are routinely performed by veterinarians and diagnostic laboratories, but also highlights recently developed tools that may improve diagnostic capabilities, including molecular and immunodiagnostic tests. Overall, diagnostic tests for parasites of livestock are an integral part of health management practices, and for assessing individual animal and herd health.

Inducing cellular immune responses with a marked Mycobacterium avium subsp. paratuberculosis strain in dairy calves

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of Johne's disease, a chronic granulomatous enteritis with a high global prevalence in dairy cattle. This disease causes significant economic loss in the dairy industry and has been challenging to control, as current diagnostic assays are low in sensitivity and specificity, and previously developed vaccines do not prevent infection and face regulatory concerns due to interference with bovine tuberculosis diagnostics. To remediate this issue, positive and negative immune markers were created in a MAP strain as a step towards a vaccine capable of differentiating infected from vaccinated animals (DIVA). A gene coding for an immunogenic protein (MAP1693c) in the MAP genome was replaced with a library of epitope-tagged immunogenic genes (pepA) via a stable allelic exchange method. These markers were evaluated in a calf infection trial, where Holstein-Friesian dairy calves were inoculated at two weeks of age with either the marked strain or the parent strain, or remained uninfected controls. Cellular immune responses to the markers were measured using an interferon gamma release assay (IGRA). There were no MAP1693c marker-specific differences in cellular immune responses between infection groups. A scrambled version of the HA (human influenza hemagglutinin) epitope, but not the actual HA epitope, induced a significant IFN-γ response in marker-infected calves compared to WT-infected and uninfected groups at 4.5 months post-inoculation. This scrambled HA epitope thus holds potential as a diagnostic tool as part of a DIVA vaccine for Johne's disease.

Serological and molecular detection of infection with Mycobacterium leprae in Brazilian six banded armadillos (Euphractus sexcinctus)

Leprosy was recognized as a zoonotic disease, associated with nine-banded armadillos (Dasypus novemcinctus) in the Southern United States of America in 2011. In addition, there is growing evidence to support a role for armadillos in zoonotic leprosy in South America. The current study evaluated twenty specimens of the six-banded armadillo (Euphractus sexcinctus), collected from rural locations in the state of Rio Grande do Norte (RN), Brazil for evidence of infection with Mycobacterium leprae. Serum was examined using two "in-house" enzyme-linked immunosorbent assays (ELISAs) and via two commercially available (ML flow and NDO-LID®) immunochromatographic lateral flow (LF) tests, for detection of the PGL-I and/or LID-1 antigens of the bacterium. The presence of M. leprae DNA in liver tissue was examined using the multi-copy, M. leprae-specific repetitive element (RLEP), as target in conventional and nested PCR assays. Molecular and anti-PGL-I-ELISA data indicated that 20/20 (100 %) of the armadillos were infected with M. leprae. The corresponding detection levels recorded with the LF tests were 17/20 (85 %) and 16/20 (85 %), for the NDO-LID® and ML flow tests, respectively. Our results indicate that, in common with D. novemcinctus, six banded armadillos (a species hunted and reared as a food-source in some regions of Brazil, including RN), represent a potential reservoir of M. leprae and as such, their role in a possible zoonotic cycle of leprosy within Brazil warrants further investigation.

New insights into the immunoproteome of B. cenocepacia J2315 using serum samples from cystic fibrosis patients

Bacteria of the Burkholderia cepacia complex (Bcc) are ubiquitous multidrug resistant organisms and opportunistic pathogens capable of causing life threatening lung infections among cystic fibrosis (CF) patients. No effective therapies are currently available to eradicate Bcc bacteria from CF patients, as these organisms are inherently resistant to the majority of clinically available antimicrobials. An immunoproteomics approach was used to identify Bcc proteins that stimulate the humoral immune response of the CF host, using bacterial cells grown under conditions mimicking the CF lung environment and serum samples from CF patients with a clinical record of Bcc infection. 24 proteins of the Bcc strain B. cenocepacia J2315 were identified as immunoreactive, 19 here reported as immunogenic for the first time. Ten proteins were predicted as extracytoplasmic, 9 of them being conserved in Bcc genomes. The immunogenic Bcc extracytoplasmic proteins are potential targets for development of novel therapeutic strategies and diagnostic tools to protect patients against the onset of chronic Bcc lung infections.

Clickable cellulosic surfaces for peptide-based bioassays

The use of peptides in paper-based analytics is a highly appealing field, yet it suffers from severe limitations. This is mostly due to the loss of effective target recognition properties of this relatively small probes upon nonspecific adsorption onto cellulose substrates. Here we address this issue by introducing a simple polymer-based strategy to obtain clickable cellulose surfaces, that we exploited for the chemoselective bioconjugation of peptide bioprobes. Our method largely outperformed standard adsorption-based immobilization strategy in a challenging, real case immunoassay, namely the diagnostic discrimination of Zika + individuals from healthy controls. Of note, the clickable polymeric coating not only allows efficient peptides bioconjugation, but it provides favorable anti-fouling properties to the cellulosic support. We envisage our strategy to broaden the repertoire of cellulosic materials manipulation and promote a renewed interest in peptide-based paper bioassays.

Parasite survey on a captive wolf population using classical techniques and ELISA coproantigen detection, USA

As laws change around the United States, wildlife that were once kept as companion animals are now often confiscated by local authorities. They are then euthanized unless a home is found for them at a sanctuary. Wolf sanctuaries are, therefore, becoming increasingly important for their conservation and management. However, little data is available on best practices for the health management of captive wolves, including data on parasitic diseases. Our objective was to assess the prevalence of parasites of captive wolves combining classical coprological techniques and immunoassays based on the detection of coproantigen of selected canid parasites. Fecal samples of 39 animals were collected upon observation of individual animals defecating. All samples were processed using the Fecal Dx® tests, a suite of coproantigen ELISAs for detection of ascarid, hookworm, whipworm, and Giardia (IDEXX Laboratories Inc.). Out of the 39 samples, 38 were processed using the double-centrifugation sugar flotation (DCSF) and 34 using a modification of the Baermann technique. Twenty-eight samples (71.8%) were positive for hookworm, and none positive for the other parasites tested using coproantigen ELISA. Ancylostoma sp. (26, 68.4%), Eucoleus boehmi (13, 34.2%), and Trichuris sp. (2; 5.3%), and Sarcocystis sp. (13, 34.2%) were detected using DCSF. No metastrongyloid lungworm larvae were found. The Cohen's kappa index (0.97) showed excellent agreement between the hookworm coproantigen ELISA and the DCSF using feces preserved in ethanol for a short period of time. This study provides a baseline on the parasites of captive wolves, and shows that recent innovative diagnostics in veterinary parasitology, developed and optimized for dogs, may be used for assessing the health of wolves.

Diagnostic performance of GM-CSF and IL-2 in response to long-term specific-antigen cell stimulation in patients with active and latent tuberculosis infection

BACKGROUND

A simple blood test for detecting active tuberculosis (TB) could be key to this epidemic containment, given that a large proportion of patients are unable to produce sputum for testing. Currently available interferon-γ release assays (IGRAs) are inadequate to diagnose active TB, with reported pooled sensitivity and specificity both under 81%.

OBJECTIVE

To explore whether cytokines/chemokines other than interferon-γ in response to long-term cell stimulation could improve the ability to distinguish between different TB infection status.

METHODS

We prospectively enrolled subjects with newly diagnosed pulmonary TB and their household contacts in Santiago. All contacts were tested with IGRA. Peripheral blood mononuclear cells were obtained and antigen-specific stimulated for 72 h before collecting their culture supernatants.

RESULTS

Subjects with active TB displayed markedly low cytokines/chemokines secretion upon PBMC stimulation, with lower GM-CSF being the best differentiator from IGRA(+) contacts, with 71% (95% CI 53-85) sensitivity, 86% (95% CI 65-97) specificity and AUC = 0.79 (p = 0.0003). On the other hand, when compared to the uninfected IGRA(-) contacts, higher level of IL-2 secretion was the best indicator of active TB, with 73.5% (95% CI 56-87) sensitivity, 85% (95% CI 66-96) specificity and AUC = 0.79 (p = 0.0001). No single cytokine/chemokine released upon stimulation could accurately differentiate between active TB and all TB contacts grouped together.

CONCLUSION

GM-CSF and IL-2 provided the best yield to differentiate active TB from latent TB and from TB uninfected, respectively, with higher specificities than that reported for IGRAs. However, none of both resulted sensitive enough to be used as a stand-alone biomarker for active TB.

Validation of IgY for the diagnosis of Streptococcus agalactiae-caused endocarditis and bacterial meningitis in Nile tilapia (Oreochromis niloticus)

Streptococcus agalactiae (Sta), which belongs to Lancefield group B, causes sepsis, endocarditis and bacterial meningitis in human neonates and Nile tilapia. Because the pathophysiology of Sta infection is partially similar in both species, the identification of biomarkers for the diagnosis and study of this disease is of importance for human and animal health. Therefore, in the present study, we produced an immunoglobulin Y (IgY) by immunizing laying hens with Sta proteins and evaluated its ability to detect Sta in paraffinized tilapia brain and cardiac tissue by direct immunofluorescence (IMF) and indirect immunohistochemistry (IHC). The IgY produced was effective in the diagnosis of Sta infection in Nile tilapia, justifying the use of this species as a biomodel for the study of this disease.

Immunogenicity of a Fap2 peptide mimotope of Fusobacterium nucleatum and its potential use in the diagnosis of colorectal cancer

Background

The role of Fusobacterium nucleatum Fap2 protein in the development of colorectal cancer has recently been explained. Fap2, when bound to the human inhibitory receptor, TIGIT, inhibits the cytotoxic activity of natural killer (NK) cells against cancer cells, thus, allowing proliferation of the latter eventually leading to tumor growth. The aim of the study was to identify the immunogenicity of a peptide mimotope of the Fap2 protein and to determine the reactivity of colorectal cancer patients’ sera against the mimotope.

Methods

Immunogenic epitope of the Fap2 protein of F. nucleatum was selected using the B-cell epitope prediction of the Immune Epitope Database and Analysis Resource (IEDB). The immunogenicity of the synthetic peptide mimotope of the Fap2 protein was determined in animal models and reactivity of colorectal cancer patients’ sera against the mimotope was done by indirect ELISA.

Results

Results show that the selected peptide mimotope, with sequence TELAYKHYFGT, of the outer membrane protein Fap2 of F. nucleatum is immunogenic. Increase in the absorbance readings of peptide-immunized rabbit sera was observed starting Week 1 which was sustained up to Week 10 in the indirect ELISA performed. Colorectal cancer cases (n = 37) were all reactive in an ELISA-based analysis using the mimotope as the capture antigen.

Conclusions

In this study, we identified an immunogenic epitope of the Fap2 protein of the Fusobacterium nucleatum. We demonstrated the reactivity of serum of histopathologically confirmed CRC patients in a peptide-capture indirect ELISA which may serve as proof of concept for the development of CRC diagnostics.

Insights into the chicken IgY with emphasis on the generation and applications of chicken recombinant monoclonal antibodies

The advantages of chicken (Gallus gallus domesticus) antibodies as immunodiagnostic and immunotherapeutic biomolecules has only been recently recognized. Even so, chicken antibodies remain less-well characterized than their mammalian counterparts. This review aims at providing a current overview of the structure, function, development and generation of chicken antibodies. Additionally, brief but comprehensive insights into current knowledge pertaining to the immunogenetic framework and diversity-generation of the chicken immunoglobulin repertoire which have contributed to the establishment of recombinant chicken mAb-generating methods are discussed. Focus is provided on the current methods used to generate antibodies from chickens with added emphasis on the generation of recombinant chicken mAbs and its derivative formats. The advantages and limitations of established protocols for the generation of chicken mAbs are highlighted. The various applications of recombinant chicken mAbs and its derivative formats in immunodiagnostics and immunotherapy are further detailed.

Dirofilaria repens microfilariae from a human node fine-needle aspirate: a case report

Background

Human dirofilariosis is still a little known infection even in endemic areas. Dirofilariosis is zoonotic infection usually abortive in humans; instead, we report a very rare case (the 4th in the world), the first in Italy, in which at least two infective larvae became mature adults that mated and produced active microfilariae even though they did not reach peripheral blood.

Case presentation

A 30-year-old Italian woman presented with a transient oedematous swelling on the left abdominal wall with a creeping eruption followed by the occurrence of a subcutaneous nodular painless mass in the iliac region. One month later, a similar temporary swelling appeared on the contralateral inguinal region associated with intermittent joint discomfort in both knees. The patient had recently travelled abroad, therefore many possible diagnoses were to be ruled out. Routine laboratory investigations revealed eosinophilia. An ultrasound examination of the iliac swelling evidenced a well-defined cyst with a big filamentous formation in continuous movement. A fine-needle aspiration of the lesion was performed for parasitological, cytological and histological exams. The prompt microscopic examination of the aspired material showed the presence of numerous microfilariae that were initially morphologically attributed to Mansonella ozzardi. Subsequently, the revision of the Giemsa stained film and molecular analyses of the biological material, allowed to identify Dirofilaria repens as etiological agent of infection.

Conclusions

We report of a case in whom microfilariae were detected in fine-needle aspirate of subcutaneous node, without evidence of microfilaraemia, and the infection failed to become fully patent. Therefore we confirm that complete development and fertilization of D. repens worms in human hosts may occur, at variance with what is commonly believed, that Dirofilaria worms cannot fully develop in humans.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1582-3) contains supplementary material, which is available to authorized users.

Viral glycoproteins: biological role and application in diagnosis

The viruses that infect humans cause a huge global disease burden and produce immense challenge towards healthcare system. Glycoproteins are one of the major components of human pathogenic viruses. They have been demonstrated to have important role(s) in infection and immunity. Concomitantly high titres of antibodies against these antigenic viral glycoproteins have paved the way for development of novel diagnostics. Availability of appropriate biomarkers is necessary for advance diagnosis of infectious diseases especially in case of outbreaks. As human mobilization has increased manifold nowadays, dissemination of infectious agents became quicker that paves the need of rapid diagnostic system. In case of viral infection it is an emergency as virus spreads and mutates very fast. This review encircles the vast arena of viral glycoproteins, their importance in health and disease and their diagnostic applications.

Antigenic properties of avian hepatitis E virus capsid protein

Avian hepatitis E virus (HEV) is the main causative agent of big liver and spleen disease and hepatitis-splenomegaly syndrome in chickens, and is genetically and antigenically related to mammalian HEVs. HEV capsid protein contains immunodominant epitopes and induces a protective humoral immune response. A better understanding of the antigenic composition of this protein is critically important for the development of effective vaccine and sensitive and specific serological assays. To date, six linear antigenic domains (I-VI) have been characterized in avian HEV capsid protein and analyzed for their applications in the serological diagnosis and vaccine design. Domains I and V induce strong immune response in chickens and are common to avian, human, and swine HEVs, indicating that the shared epitopes hampering differential diagnosis of avian HEV infection. Domains III and IV are not immunodominant and elicit a weak immune response. Domain VI, located in the N-terminal region of the capsid protein, can also trigger an intense immune response, but the anti-domain VI antibodies are transient. The protection analysis showed that the truncated capsid protein containing the C-terminal 268 amino acid residues expressed by the bacterial system can provide protective immunity against avian HEV infection in chickens. However, the synthetic peptides incorporating the different linear antigenic domains (I-VI) and epitopes are non-protective. The antigenic composition of avian HEV capsid protein is altogether complex. To develop an effective vaccine and accurate serological diagnostic methods, more conformational antigenic domains or epitopes are to be characterized in detail.

Development of a Dual Path Platform (DPP®) immunoassay for rapid detection of Candida albicans in human whole blood and serum

Candida albicans is an opportunistic pathogen which can lead to Candidiasis and blood-stream infections, resulting in a mortality rate near 40%. Given its high fatality and emerging pathogenicity, there is a strong need for the development of a rapid C. albicans diagnostic assay. Point-of-care devices, specifically lateral flow assays, are an attractive and often employed diagnostic modality for C. albicans detection. However, they lack the required performance characteristics needed for accurate pathogen detection and subsequent treatment options. Thus, we describe herein the utility of the Dual Path Platform (DPP®) device as an immunochromatographic Point-of-care assay for C. albicans. The limit of detection for hyphal and budding C. albicans in DPP® tests are reported to be as low as 7.94 × 10(5) whole cells/mL in human serum. C. albicans cells were detected with up to a 3.9 fold increase in sensitivity on DPP® when compared to conventional lateral flow modalities.

[Protein arrays and perspectives of medical applications]

Protein microarrays make it possible to detect molecular interactions with various partners (proteins, peptides, nucleic acids, sugars, etc.). Their advantages are crucial for high-throughput analysis of proteomes of different organisms. Moreover, the recent data reveal the performance of microarrays over current immunological methods. Therefore, the antigen and antibody microarrays become indispensable for medical applications, in particular, for diagnosis and prognosis of microbial infections, autoimmune and allergic diseases. The further technological progress might provide the extension of the miniaturized assays for multiparametric monitoring of human pathologies in practical medicine.

In vitro released antigens in diagnosis and immunomonitoring of filaria and tuberculosis

In vitro released antigens by living parasites or bacteria underin vitro maintenance or short term culture showing specific humoral immune response have been explored in development of immunodiagnostics for infectious diseases such as filariasis and tuberculosis in our laboratory. ELISA usingB. malayi mf ES antigen has been explored for detecting IgG antibody by Indirect ELISA and antigen by Inhibition ELISA and in immunomonitoring of carriers as well as clinical filarial cases. A ten year follow up of mf carriers with DEC therapy showed disapperance of antigen and antibody followed by reappearance in few cases in an endemic area. None of the cases followed developed clinical symptoms suggesting the need for long term monitoring and treatment of microfilaraemic carriers. Further immunomonitoring was found to be useful in confirming filaria aetiology in the absence of microfilaremia and determining appropriate period of treatment of acute, early clinical and occult filarial infections for clinical relief and cure.Indirect Stick Penicillinase ELISA system using Mtb EST-6 antigen for detecting tuberculous IgG antibody and a Sandwich Penicillinase ELISA system using affinity purified antibody for detecting circulating antigen were explored in tuberculosis. A combination of both the assay systems with a sensitivity of 70% and specificity of 98% was found to be promising in the precise diagnosis of pulmonary tuberculosis. Further antigen detection was found to be useful in bone and joint tuberculosis.