Evaluation of cross-reactivity to Taenia hydatigena and Echinococcus granulosus in the enzyme-linked immunoelectrotransfer blot assay for the diagnosis of porcine cysticercosis

Antibody Banding Patterns on the Enzyme-Linked Immunoelectrotransfer Blot (EITB) Assay Clearly Discriminate Viable Cysticercosis in Naturally Infected Pigs

Enzyme-linked immunoelectrotransfer blot (EITB) detects antibodies against seven Taenia solium larvae antigens in three protein families (GP50, T24/42, and 8-kDa) with different structures and functions. EITB banding patterns against these antigens in pigs provide information about the course of infection and may discriminate viable cysticercosis. We analyzed the banding patterns and infection outcomes (presence of viable cysts, degenerated cysts, and any cysts) of 512 rural pigs. Banding patterns were grouped into homogenous classes using latent class analysis, and relationships with infection outcomes were assessed. Four classes were identified: 1 (n = 308, EITB-negative or positive for the GP50 family), 2 (n = 127, positive for GP50 (GP50 family), GP42-39 and GP24 (T24/42 family), but negative for 8-kDa antigens), 3 (n = 22, positive for GP50 and T24/42 antigens (GP42-39 and GP24), as well as to 8-kDa bands GP13, GP14, and GP18, but negative for GP21), and 4 (n = 55, positive for GP50 and T24/42 antigens, as well as to 8-kDa antigens GP21 and GP18 in combination). Pigs in classes 3 and 4 were more likely to have viable cysts (72.6% and 96.4%, respectively) than pigs in classes 1 and 2 (0.7% and 27.6%, respectively; p < 0.001). The number of infections with any cysts was higher in classes 3 and 4 (77.3% and 98.2%, respectively) and lower in classes 2 and 1 (34.7% and 4.9%, respectively; p < 0.001). Pigs with viable cysts represented >90% of pigs with any cysts in classes 3 and 4 (94.1% and 98.2%, respectively), while degenerated cysts were frequent among pigs with any cysts in classes 1, 3, and 2 (86.7%, 47.1%, and 43.2%, respectively; p < 0.001). EITB banding patterns strongly correlate with cysticercosis infection status in rural pigs, with classes 3 and 4 being more predictive of viable infections.

Spatial transferability of an agent-based model to simulate Taenia solium control interventions

BACKGROUND

Models can be used to study and predict the impact of interventions aimed at controlling the spread of infectious agents, such as Taenia solium, a zoonotic parasite whose larval stage causes epilepsy and economic loss in many rural areas of the developing nations. To enhance the credibility of model estimates, calibration against observed data is necessary. However, this process may lead to a paradoxical dependence of model parameters on location-specific data, thus limiting the model's geographic transferability.

METHODS

In this study, we adopted a non-local model calibration approach to assess whether it can improve the spatial transferability of CystiAgent, our agent-based model of local-scale T. solium transmission. The calibration dataset for CystiAgent consisted of cross-sectional data on human taeniasis, pig cysticercosis and pig serology collected in eight villages in Northwest Peru. After calibration, the model was transferred to a second group of 21 destination villages in the same area without recalibrating its parameters. Model outputs were compared to pig serology data collected over a period of 2 years in the destination villages during a trial of T. solium control interventions, based on mass and spatially targeted human and pig treatments.

RESULTS

Considering the uncertainties associated with empirical data, the model produced simulated pre-intervention pig seroprevalences that were successfully validated against data collected in 81% of destination villages. Furthermore, the model outputs were able to reproduce validated pig seroincidence values in 76% of destination villages when compared to the data obtained after the interventions. The results demonstrate that the CystiAgent model, when calibrated using a non-local approach, can be successfully transferred without requiring additional calibration.

CONCLUSIONS

This feature allows the model to simulate both baseline pre-intervention transmission conditions and the outcomes of control interventions across villages that form geographically homogeneous regions, providing a basis for developing large-scale models representing T. solium transmission at a regional level.

What about the Cytoskeletal and Related Proteins of Tapeworms in the Host's Immune Response? An Integrative Overview

Recent advances have increased our understanding of the molecular machinery in the cytoskeleton of mammalian cells, in contrast to the case of tapeworm parasites, where cytoskeleton remains poorly characterized. The pertinence of a better knowledge of the tapeworm cytoskeleton is linked to the medical importance of these parasitic diseases in humans and animal stock. Moreover, its study could offer new possibilities for the development of more effective anti-parasitic drugs, as well as better strategies for their surveillance, prevention, and control. In the present review, we compile the results of recent experiments on the cytoskeleton of these parasites and analyze how these novel findings might trigger the development of new drugs or the redesign of those currently used in addition to supporting their use as biomarkers in cutting-edge diagnostic tests.

Past and Present of Diagnosis of Echinococcosis: A Review (1999-2021)

The larval forms of taeniid cestodes belonging to the genus Echinococcus are the source of the zoonotic infection known as echinococcosis. Alveolar and cystic echinococcosis are caused by Echinococcus multilocularis and Echinococcus granulosus (s. s) respectively. It is endemic in several regions of the world. In this systematic review, we describe diagnosis, and the species (human, canids, livestock, and small rodents) affected by cystic (CE) and alveolar echinococcosis (AE). From 1999 to 2021, we searched the online directory through PubMed, SCOPUS, Web of Science, and google scholar. Among the 37,700 records found in the online databases, 187 publications met our eligibility requirements. The majority of investigations employed a range of diagnostic methods, such as ELISA, imaging, copro-PCR, necropsy or arecoline hydrobromide purgation, morphological cestode confirmation, and fecal sieving/flotation to detect and confirm Echinococcus infection. ELISA was the most commonly used method followed by PCR, and imaging. The research team retrieved data describing the incidence or assessment of the diagnostic test for E. multilocularis in humans (N = 99), canids (N = 63), small ruminants (N = 13), large ruminants (N= 3), camel (N= 2), pigs (N=2) and small mammals (N= 5). This study was conducted to explore the diagnostic tools applied to detect echinococcosis in humans as well as animals in prevalent countries, and to report the characteristic of new diagnostic tests for disease surveillance. This systematic review revealed that ELISA (alone or in combination) was the most common method used for disease diagnosis and diagnostic efficacy and prevalence rate increased when recombinant antigens were used. It is highly recommended to use combination protcols such as serological with molecular and imaging technique to diagnose disease. Our study identified scarcity of data of reporting echinococcosis in humans/ animals in low-income or developing countries particularly central Asian countries. Study reports in small rodents indicate their role in disease dissemination but real situation in these host is not refected due to limited number of studies. Even though echinococcosis affects both public health and the domestic animal sector, therefore, it is important to devise new and strengthe implementation of the existing monitoring, judging, and control measures in this estimate.

Evaluating the Role of Corrals and Insects in the Transmission of Porcine Cysticercosis: A Cohort Study

The widespread dispersion of pigs infected with cysticercosis across endemic villages, low cyst burden among infected pigs, and low prevalence of taeniasis all suggest that pig ingestion of human feces is not the only mode of transmission for Taenia solium. Our objective was to evaluate the risk of porcine cysticercosis associated with exposure to human feces, dung beetles, and flies in an endemic community setting. We used a cluster-randomized cohort design to compare the risk of developing antibodies and infection among 120 piglets raised in either free-roaming (FR), standard corral (SC), or netted corral environments (NC). We collected monthly blood samples to detect serum antibodies and necropsied all pigs after 10 months to identify cysts. A total of 66 piglets developed antibodies with the relative risk of seropositivity in FR vs. all corralled pigs increasing significantly after 18 weeks. Of 108 necropsied pigs, 15 had T. solium cysts, all belonging to the FR group. Corrals were protective against infection but less so against seropositivity. NC, which did not completely exclude insects, did not provide added protection against seropositivity as compared to SC. The results of this study suggest that dung beetles and flies do not play an important role in infection.

The prevalence of Taenia spp. in pigs slaughtered in Kinshasa

Taenia hydatigena is a non-zoonotic worm that has dogs and wild canids as definitive hosts. Its presence induces cross reactions in certain diagnostic tests for porcine cysticercosis caused by T. solium, the occurrence of which has a considerable public health and economic impact. In the Democratic Republic of the Congo (DR Congo), T. solium is considered endemic, however, the prevalence of T. hydatigena has not been estimated yet. The objective of the study was therefore to estimate the prevalence of T. hydatigena cysticercosis by serological and molecular diagnostic tools in pigs slaughtered in DR Congo. A total of 480 pigs slaughtered in 6 slaughter slabs in Kinshasa, DR Congo, were examined. The thoracal and abdominal cavity organs were inspected for cysts, which were analyzed using PCR-RFLP. Furthermore, 480 sera were collected, and analyzed for the presence of circulating Taenia spp. cysticercus antigens, using the B158/B60 Ag-ELISA. Upon inspection of the carcass, 41 cysts suspected to be metacestodes of Taenia spp. were collected, from the following viscera: spleen (24/41, 59%), liver (13/41, 32%), intestine (3/41, 7%) and lung (1/41, 2%). Molecular analyses revealed a T. hydatigena prevalence of 0.2% (95% CI: 0.0001-0.0116), based on a single lesion (1/480), taken from the spleen. Out of the 480 sera collected, the presence of circulating Taenia spp. cysticerci antigens was detected in 32 (6.7%; 95% CI: 4.5-11.2). The results of this study revealed that T. hydatigena is present in pigs sold in markets in the city of Kinshasa in DR Congo, albeit at a very low prevalence, thus the impact on the interpretation of the B158/B60 seems low in this setting. Detection of circulating antigens in porcine sera by Ag-ELISA, shows that pigs slaughtered in Kinshasa, DR Congo, were infected with viable cysticerci of Taenia spp. which in turn can infect humans.

Non-local validated parametrization of an agent-based model of local-scale Taenia solium transmission in North-West Peru

The pork tapeworm, Taenia solium, is the cause of a preventable zoonotic disease, cysticercosis, affecting both pigs and humans. Continued endemic transmission of T. solium is a major contributor of epilepsy and other neurologic morbidity, and the source of important economic losses, in many rural areas of developing countries. Simulation modelling can play an important role in aiding the design and evaluation of strategies to control or even eliminate transmission of the parasite. In this paper, we present a new agent based model of local-scale T. solium transmission and a new, non-local, approach to the model calibration to fit model outputs to observed human taeniasis and pig cysticercosis prevalence simultaneously for several endemic villages. The model fully describes all relevant aspects of T. solium transmission, including the processes of pig and human infection, the spatial distribution of human and pig populations, the production of pork for human consumption, and the movement of humans and pigs in and out in several endemic villages of the northwest of Peru. Despite the high level of uncertainty associated with the empirical measurements of epidemiological data associated with T. solium, the non-local calibrated model parametrization reproduces the observed prevalences with an acceptable precision. It does so not only for the villages used to calibrate the model, but also for villages not included in the calibration process. This important finding demonstrates that the model, including its calibrated parametrization, can be successfully transferred within an endemic region. This will enable future studies to inform the design and optimization of T. solium control interventions in villages where the calibration may be prevented by the limited amount of empirical data, expanding the possible applications to a wider range of settings compared to previous models.

Evaluation of recombinant glutathione transferase 26 kDa, thioredoxin-1, and endophilin B1 of Taenia solium in the diagnosis of human neurocysticercosis

Neurocysticercosis caused by Taenia solium larvae is a neglected disease that persists in several countries, including Mexico, and causes a high disability-adjusted life year burden. Neuroimaging tools such as computed tomography and magnetic resonance imaging are the most efficient for its detection, but low availability and high costs in most endemic regions limit their use. Serological methods such as lentil lectin-purified glycoprotein enzyme-linked immunoelectrotransfer blot antibody detection and monoclonal antibody-based enzyme-linked immunosorbent assays for HP10 antigen detection have been useful in supporting the diagnosis of this disease. We evaluated three T. solium recombinant antigens: glutathione transferase of 26 kDa (Ts26GST); thioredoxin-1 (TsTrx-1), and endophilin B1 (TsMEndoB1) by EITB. These are antigenic proteins antigenic, abundant in excretion/secretion products of the parasite, and do not cross-react with homologous host proteins. Ts26GST and TsTrx-1 showed sensitivity of 79 and 88%, specificity of 86 and 97%, PPV of 83 and 97% and NPV of 82 and 91%, respectively, for neurocysticercosis diagnosis. The recombinant antigens allowed the diagnosis of 70% (Ts26GST) and 80% (TsTrx-1) of patients having only one cysticercus. Further studies on specific regions of these proteins could improve T. solium diagnostics.

Rapid Detection of Cysticercus cellulosae by an Up-Converting Phosphor Technology-Based Lateral-Flow Assay

Cysticercosis is a neglected tropical disease caused by the larvae of Taenia solium in pigs and humans. The current diagnosis of porcine cysticercosis is difficult, and traditional pathological tests cannot meet the needs of detection. This study established a UPT-LF assay for the detection of Cysticercus cellulosae. UCP particles were bound to two antigens, TSOL18 and GP50; samples were captured, and the signal from the UCP particles was converted into a detectable signal for analysis using a biosensor. Compared to ELISA, UPT-LF has higher sensitivity and specificity, with a sensitivity of 93.59% and 97.44%, respectively, in the case of TSOL18 and GP50 antigens and a specificity of 100% for both. Given its rapidness, small volume, high sensitivity and specificity, and good stability and reproducibility, this method could be used in the diagnosis of cysticercosis.

Validation of a spatial agent-based model for Taenia solium transmission ("CystiAgent") against a large prospective trial of control strategies in northern Peru

BACKGROUND

The pork tapeworm (Taenia solium) is a parasitic helminth that imposes a major health and economic burden on poor rural populations around the world. As recognized by the World Health Organization, a key barrier for achieving control of T. solium is the lack of an accurate and validated simulation model with which to study transmission and evaluate available control and elimination strategies. CystiAgent is a spatially-explicit agent based model for T. solium that is unique among T. solium models in its ability to represent key spatial and environmental features of transmission and simulate spatially targeted interventions, such as ring strategy.

METHODS/PRINCIPAL FINDINGS

We validated CystiAgent against results from the Ring Strategy Trial (RST)-a large cluster-randomized trial conducted in northern Peru that evaluated six unique interventions for T. solium control in 23 villages. For the validation, each intervention strategy was replicated in CystiAgent, and the simulated prevalences of human taeniasis, porcine cysticercosis, and porcine seroincidence were compared against prevalence estimates from the trial. Results showed that CystiAgent produced declines in transmission in response to each of the six intervention strategies, but overestimated the effect of interventions in the majority of villages; simulated prevalences for human taenasis and porcine cysticercosis at the end of the trial were a median of 0.53 and 5.0 percentages points less than prevalence observed at the end of the trial, respectively.

CONCLUSIONS/SIGNIFICANCE

The validation of CystiAgent represented an important step towards developing an accurate and reliable T. solium transmission model that can be deployed to fill critical gaps in our understanding of T. solium transmission and control. To improve model accuracy, future versions would benefit from improved data on pig immunity and resistance, field effectiveness of anti-helminthic treatment, and factors driving spatial clustering of T. solium infections including dispersion and contact with T. solium eggs in the environment.

Force-of-infection of Taenia solium porcine cysticercosis: a modelling analysis to assess global incidence and prevalence trends

The World Health Organization (WHO) called, in 2012, for a validated strategy towards Taenia solium taeniasis/cysticercosis control and elimination. Estimating pig force-of-infection (FoI, the average rate at which susceptible pigs become infected) across geographical settings will help understand local epidemiology and inform effective intervention design. Porcine cysticercosis (PCC) age-prevalence data (from 15 studies in Latin America, Africa and Asia) were identified through systematic review. Catalytic models were fitted to the data using Bayesian methods, incorporating uncertainty in diagnostic performance, to estimate rates of antibody seroconversion, viable metacestode acquisition, and seroreversion/infection loss. There was evidence of antibody seroreversion across 5 studies, and of infection loss in 6 studies measured by antigen or necropsy, indicating transient serological responses and natural resolution of infection. Concerted efforts should be made to collect robust data using improved diagnostics to better understand geographical heterogeneities in T. solium transmission to support post-2020 WHO targets.

Occurrence of Taenia species in pigs in slaughterhouses in Phu Tho province, northern Vietnam

Pigs act as the intermediate hosts of the zoonotic tapeworms Taenia solium and Taenia asiatica, as well as of the non-zoonotic Taenia hydatigena. In Vietnam, human taeniasis and cysticercosis have been reported throughout the country; however, data on porcine cysticercosis are scarce. Our study aimed to estimate the prevalence of Taenia spp. in slaughtered pigs in two districts in Phu Tho, a mountainous province in northern Vietnam from where neurocysticercosis patients commonly originate. The carcasses of 399 pigs from 51 small-scale abattoirs were checked for cysticerci, while tongue, liver, masseter muscles, diaphragm and heart were sliced and examined. Retrieved cysticerci underwent polymerase chain reaction-restriction fragment length polymorphism and sequencing for species confirmation. Blood was also collected to detect antibodies by lentil lectin-purified glycoprotein enzyme-linked immunoelectrotransfer blot (LLGP-EITB) and recombinant T24H antigen (rT24H)-EITB and circulating antigens by B158/B60 Ag-ELISA. In two pigs, T. asiatica cysticerci were found, confirming the presence of the parasite in pigs in Vietnam at a low prevalence (0.5%; 95% exact confidence interval (CI): 0-1.19%). Cysticerci of T. solium were found in none of the pigs, although one serum sample was positive for antibodies in both LLGP-EITB and rT24H-EITB. Furthermore, a high prevalence of T. hydatigena cysticercosis was observed (18.0%; 95% Wilson score CI: 14.6-22.1%). In more than half of the T. hydatigena-positive pigs, circulating antigens were detected by Ag-ELISA, confirming that this test cannot be used to diagnose T. solium cysticercosis in this region. Finally, Spirometra erinaceieuropaei was found in one pig liver. It is the first record of this zoonotic cestode species in pigs in Vietnam. Overall, the findings confirmed the complex epidemiology of Taenia spp. in pigs in Vietnam.

PREVALENCE OF PORCINE CYSTICERCOSIS AMONG SCAVENGING PIGS IN WESTERN KENYA

BACKGROUND

Porcine Cysticercosis (PC) infection is globally classified as a neglected and re-emerging tropical disease. The disease is endemic in Western Kenya yet smallholder farmers continue to practice scavenging pig production, thereby posing public health risk. This study determined the prevalence of PC infection at the farms and slaughter slabs in a cross-sectional survey in two Counties (Busia and Kakamega) of Western Kenya.

MATERIALS AND METHODS

Two hundred and eighty-seven (287) heparinized blood samples were collected at the farm from 162 households in 9 villages and 113 pigs from 5 slaughter slabs. The prevalence of PC was detected through meat inspection at slaughter slabs, and the prevalence of Taenia solium antigen determined by using the ApDia Ag-ELISA test at the farms and slaughter slabs.

RESULTS

At meat inspection, the PC prevalence was 1.8%, while prevalence of Taenia Species cysts detected with Ag-ELISA test was 3.8% at the farms, and 5.3 % at the slaughter slabs. The Ag-ELISA test had sensitivity of 100% (95% CI: 19.79- 100.00) and specificity of 96.4% (95% CI: 90.49- 98.84).

CONCLUSION

The PC prevalence levels observed among scavenging pigs in Western Kenya should be a cause of public health risk concern. This observation warrant enforcing mandatory pig confinement, and use of latrines at the farms and meat inspection at local slaughter slabs. Further studies are recommended to identify different Taenia species in cysticercoids pigs in the region, which this study could not differentiate.

Taenia solium cysticercosis and taeniasis in urban settings: Epidemiological evidence from a health-center based study among people with epilepsy in Dar es Salaam, Tanzania

In Africa, urbanization is happening faster than ever before which results in new implications for transmission of infectious diseases. For the zoonotic parasite Taenia solium, a major cause of acquired epilepsy in endemic countries, the prevalence in urban settings is unknown. The present study investigated epidemiological, neurological, and radiological characteristics of T. solium cysticercosis and taeniasis (TSCT) in people with epilepsy (PWE) living in Dar es Salaam, Tanzania, one of the fastest growing cities worldwide. A total of 302 PWE were recruited from six health centers in the Kinondoni district of Dar es Salaam. Serological testing for T. solium cysticercosis-antigen (Ag) and -antibodies (Abs) and for T. solium taeniasis-Abs was performed in all PWE. In addition, clinical and radiological examinations that included cranial computed tomography (CT) were performed. With questionnaires, demographic data from study populations were collected, and factors associated with TSCT were assessed. Follow-up examinations were conducted in PWE with TSCT. T. solium cysticercosis-Ag was detected in three (0.99%; 95% CI: 0–2.11%), -Abs in eight (2.65%; 95% CI: 0.84–4.46%), and taeniasis-Abs in five (1.66%; 95% CI: 0.22–3.09%) of 302 PWE. Six PWE (1.99%; 95% CI: 0.41–3.56%) were diagnosed with neurocysticercosis (NCC). This study demonstrates the presence of TSCT in Dar es Salaam, however, NCC was only associated with a few cases of epilepsy. The small fraction of PWE with cysticercosis- and taeniasis-Abs may suggest that active transmission of T. solium plays only a minor role in Dar es Salaam. A sufficiently powered risk analysis was hampered by the small number of PWE with TSCT; therefore, further studies are required to determine the exact routes of infection and risk behavior of affected individuals.

Taenia solium cysticercosis and taeniasis is a zoonotic disease complex which affects thousands of people in sub-Saharan Africa. This parasite has a human-pig life cycle and has been considered a public health problem mainly in rural areas. As African towns and suburbs grow rapidly and disproportionally, adequate infrastructure such as sewage systems and clean water often lack while population density, trade, and travel increase. This may lead to the appearance of parasitic diseases formerly considered `rural´ in urban settings. In this study, we searched for evidence of T. solium infections in the Kinondoni district of Dar es Salaam, Tanzania. We focused on people with epilepsy (PWE) since epilepsy is one of the most common and severe disorders associated with T. solium neurocysticercosis and tested all of them serologically for T. solium cysticercosis and taeniasis. We further investigated neurological and radiological characteristics. Our findings show that in our study area in Dar es Salaam 2.65% of PWE had contracted T. solium infection at some stage. Neurocysticercosis, as confirmed by neuroimaging, was found only in 1.99% of PWE. This, in combination with the relatively small number of PWE detected with taeniasis antibodies (1.66%), points towards the fact that active transmission of T. solium seems to play only a minor role in this urban setting, suggesting that infections may mainly be contracted in rural areas. Further large-scale studies are required to investigate the infection pathways and risk behavior related to T. solium infections within urban areas of sub-Saharan Africa.

Further evaluation of recombinant Tsol-p27 by enzyme-linked immunoelectrotransfer blot for the serodiagnosis of cysticercosis in pigs from Mozambique

BACKGROUND

Porcine cysticercosis has a negative impact on human health and the meat industry, as it makes infected meat unaproprieted for consuption and it is the main etiology of epileptic seizures in developing countries. There are multiple serological assays that use crude antigens with high sensitivity and specificity for the diagnosis of both porcine and human cysticercosis. Nonetheless, antigen preparation is time-consuming, needs a well-equipped laboratory and trained personnel and places those manipulating the meat at great risk for infection. New serodiagnostic approaches to the diagnosis of porcine and human cysticercosis have been directed towards the development of recombinant deoxyribonucleic acid technology for the generation of synthetic proteins that can serve as simplified, low-cost and harmless substitutes for native antigens. The aim of the present study was to further evaluate the recombinant Tsol-p27 protein as a target molecule in immunoassays for the serodiagnosis of porcine cysticercosis. From these data, we hoped to develop recommendations regarding its use in the serodiagnosis of porcine cysticercosis.

RESULTS

We studied a panel of 83 naturally infected pig sera from Angónia District, Mozambique, an endemic area for porcine and human cysticercosis. These sera were previously tested by antigen enzyme-linked immunosorbent assay (Ag-ELISA) to detect antigens of T. solium. The serum panel was processed by enzyme-linked immunoelectrotransfer blot (EITB) assay against the recombinant Tsol-p27 protein and the Ag-ELISA assay results were used to compare and evaluate the performance of Tsol-p27 for the diagnosis of cysticercosis. Out of 83 sera, 24 (29.0%) were positive for Tsol-p27 and 59 (71%) were negative in the same assay. From the 37 sera that tested positive to Ag-ELISA, 11 (13.3%) were positive to Tsol-p27, while from 46 sera that tested negative to Ag-ELISA, 33 (39.7%) also tested negative to Tsol-p27. The sensitivity and specificity of Tsol-p27 was 29.7% and 71.7%, respectively, while the positive predictive value and negative predictive value were 45.8% and 55.9%, respectively, as calculated using Medcalc® version 15.0 software (MedCalc Software, Ostend, Belgium).

CONCLUSION

While Tsol-p27 recombinant protein might be suitable for testing human sera, its performance in pigs is not acceptable, so other recombinant proteins should be evaluated alone or multiplexed.