scholarly journals Deciphering Antibody Responses to Orthonairoviruses in Ruminants

2021 ◽  
Vol 9 (7) ◽  
pp. 1493
Author(s):  
Julia Hartlaub ◽  
Markus Keller ◽  
Martin H. Groschup
Keyword(s):  
Indirect Immunofluorescence ◽  
Neutralization Test ◽  
Hemorrhagic Fever ◽  
Antibody Responses ◽  
Virus Neutralization Test ◽  
Human Pathogen ◽  
N Protein ◽  
Cross Reactions ◽  
Test Formats ◽  
Heterologous Virus

Antibody cross-reactivities between related viruses are common diagnostic challenges, resulting in reduced diagnostic specificities and sensitivities. In this study, antibody cross-reactions between neglected members of the genus Orthonairovirus—Hazara (HAZV), Dugbe (DUGV), and Nairobi sheep disease orthonairovirus (NSDV)—were investigated. Mono-specific ovine and bovine sera following experimental infections as well immunization trials with HAZV, DUGV, and NSDV were tested in homologous and heterologous virus-specific assays, namely indirect ELISAs based on recombinant N protein, indirect immunofluorescence assays (iIFA), and two neutralization test formats (plaque reduction neutralization test (PRNT) and micro-virus neutralization test (mVNT)). The highest specificities were achieved with the ELISAs, followed by the mVNT, iIFA, and PRNT. Cross-reactivities were mainly observed within the Nairobi sheep disease serogroup–but surprisingly, HAZV antibodies in PRNT did also neutralize NSDV and DUGV. In conclusion, we recommend ELISAs and mVNTs for a discriminative diagnostic approach to differentiate between these antibodies. NSDV antisera were also used in serological assays for the detection of antibodies against the human pathogen Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV). Interestingly, all CCHFV ELISAs (In-house and commercial) achieved high diagnostic specificities, whereas significant cross-reactivities were observed in a CCHFV iIFA. Previously, similar results were obtained when analyzing the HAZV and DUGV antisera.

scholarly journals Cross-Reaction or Co-Infection? Serological Discrimination of Antibodies Directed against Dugbe and Crimean-Congo Hemorrhagic Fever Orthonairovirus in Nigerian Cattle

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1398
Author(s):  
Julia Hartlaub ◽  
Oluwafemi B. Daodu ◽  
Balal Sadeghi ◽  
Markus Keller ◽  
James Olopade ◽  
...  
Keyword(s):  
Indirect Immunofluorescence ◽  
Hemorrhagic Fever ◽  
Immunofluorescence Assay ◽  
Cross Reaction ◽  
African Countries ◽  
Crimean Congo Hemorrhagic Fever ◽  
Transmission Cycle ◽  
N Protein ◽  
Seroprevalence Data ◽  
Human Infections

Dugbe orthonairovirus (DUGV) and Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) are tick-borne arboviruses within the order Bunyavirales. Both viruses are endemic in several African countries and can induce mild (DUGV, BSL 3) or fatal (CCHFV, BSL 4) disease in humans. Ruminants play a major role in their natural transmission cycle. Therefore, they are considered as suitable indicator animals for serological monitoring studies to assess the risk for human infections. Although both viruses do not actually belong to the same serogroup, cross-reactivities have already been reported earlier—hence, the correct serological discrimination of DUGV and CCHFV antibodies is crucial. In this study, 300 Nigerian cattle sera (150 CCHFV seropositive and seronegative samples, respectively) were screened for DUGV antibodies via N protein-based ELISA, indirect immunofluorescence (iIFA) and neutralization assays. Whereas no correlation between the CCHFV antibody status and DUGV seroprevalence data could be demonstrated with a newly established DUGV ELISA, significant cross-reactivities were observed in an immunofluorescence assay. Moreover, DUGV seropositive samples did also cross-react in a species-adapted commercial CCHFV iIFA. Therefore, ELISAs seem to be able to reliably differentiate between DUGV and CCHFV antibodies and should preferentially be used for monitoring studies. Positive iIFA results should always be confirmed by ELISAs.

scholarly journals Experimental Challenge of Sheep and Cattle with Dugbe Orthonairovirus, a Neglected African Arbovirus Distantly Related to CCHFV

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 372
Author(s):  
Julia Hartlaub ◽  
Felicitas von Arnim ◽  
Christine Fast ◽  
Ali Mirazimi ◽  
Markus Keller ◽  
...  
Keyword(s):  
Neutralization Test ◽  
Clinical Signs ◽  
Febrile Illness ◽  
Hemorrhagic Fever ◽  
African Countries ◽  
Transmission Cycle ◽  
N Protein ◽  
Diagnostic Assays ◽  
Subcutaneous Inoculation ◽  
Experimental Challenge

Dugbe orthonairovirus (DUGV) is a tick-borne arbovirus within the order Bunyavirales. DUGV was first isolated in Nigeria, but virus isolations in ten further African countries indicate that DUGV is widespread throughout Africa. Humans can suffer from a mild febrile illness, hence, DUGV is classified as a biosafety level (BSL) 3 agent. In contrast, no disease has been described in animals, albeit serological evidence exists that ruminants are common hosts and may play an important role in the transmission cycle of this neglected arbovirus. In this study, young sheep and calves were experimentally inoculated with DUGV in order to determine their susceptibility and to study the course of infection. Moreover, potential antibody cross-reactivities in currently available diagnostic assays for Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) were assessed as DUGV is distantly related to CCHFV. Following subcutaneous inoculation, none of the animals developed clinical signs or viremia. However, all ruminants seroconverted, as demonstrated by two DUGV neutralization test formats (micro-virus neutralization test (mVNT), plaque reduction (PRNT)), by indirect immunofluorescence assays and in bovines by a newly developed DUGV recombinant N protein ELISA. Sera did not react in commercial CCHFV ELISAs, whereas cross-reactivities were observed by immunofluorescence and immunoblot assays.

scholarly journals Bovine Herpesvirus Type 4 (BoHV-4) Vector Delivering Nucleocapsid Protein of Crimean Congo Hemorrhagic Fever Virus Induces Comparable Protective Immunity against Lethal Challenge in IFNAR-/- Mice Model

2019 ◽  
Author(s):  
Touraj Aligholipour Farzani ◽  
Katalin Földes ◽  
Alireza Hanifehnezhad ◽  
Burcu Yener Ilce ◽  
Seval Bilge Dagalp ◽  
...  
Keyword(s):  
Specific Antibody ◽  
Bovine Herpesvirus ◽  
Hemorrhagic Fever ◽  
Fever Virus ◽  
Antibody Responses ◽  
Lethal Challenge ◽  
Crimean Congo Hemorrhagic Fever ◽  
Herpesvirus Type ◽  
N Protein ◽  
Hemorrhagic Fever Virus

Crimean-Congo hemorrhagic fever virus (CCHFV) is the causative agent of a tick-borne infection with significant mortality rate of up to 40% in the endemic areas, with evidence for geographical expansion. Lacking effective therapeutics and control measures, the development of protective CCHFV vaccine remains a crucial public health task. This manuscript describes, for the first time, a Bovine herpesvirus type 4 (BoHV-4) based viral vector (BoHV4-∆TK-CCHFV-N) and its immunogenicity and protection potential in BALB/c and IFNAR-/- mice models in comparison with Adenovirus type 5 (Ad5-N) and pCDNA3.1 myc/His A (pCD-N1), two widely used vaccine platforms. All constructs expressing viral nucleocapsid (N) protein successfully elicited cytokine and total/specific antibody responses in BALB/c mice. BoHV4-∆TK-CCHFV-N and Ad5-N constructs further produced 100% protection in IFNAR-/- mice during CCHFV Ank-2 strain lethal challenge. Despite elevated specific antibody responses in both animal models, the produced antibodies were unable to neutralize the virus in vitro. A comparison of delivery platforms was not possible, due to similar protection rates in IFNAR-/- mice. In conclusion, vector-based CCHFV N protein expression proved to constitute an effective approach for the vaccine development pipeline and BoHV-4 emerged as a strong alternative to previously-used virus vectors.

scholarly journals Five Commercial Immunoassays for SARS-CoV-2 Antibody Determination and Their Comparison and Correlation with the Virus Neutralization Test

Diagnostics ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 593
Author(s):  
Václav Šimánek ◽  
Ladislav Pecen ◽  
Zuzana Krátká ◽  
Tomáš Fürst ◽  
Hana Řezáčková ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralization Test ◽  
Young Patients ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Age Dependent ◽  
Previous Contact ◽  
Dependent Elderly ◽  
Protein Assays ◽  
Antibody Determination

There is an ongoing debate as to whether SARS-CoV-2 antibodies can be found in patients who have recovered from COVID-19 disease. Currently, there is no consensus on whether the antibodies, if present, are protective. Our regular measurements of SARS-CoV-2 antibodies, starting in July 2020, have provided us with the opportunity of becoming acquainted with the five different immunoassays. A total of 149 patients were enrolled in our study. We measured the samples using each immunoassay, then performing a virus neutralization test and comparing the results of SARS-CoV-2 antibodies with this test. We observed that the production of neutralizing antibodies is age-dependent. Elderly patients have a higher proportion of high neutralizing titers than young patients. Based on our results, and in combination with the literature findings, we can conclude that the serological SARS-CoV-2 antibody measurement is a helpful tool in the fight against COVID-19. The assays can provide information about the patient’s previous contact with the virus. Anti-spike protein assays correlate well with the virus neutralization test and can be used in the screening of potential convalescent plasma donors.

scholarly journals Naturally induced auto-anit-idiotypic antibodies. Induction by identical idiotopes in some members of an outbred rabbit family.

1982 ◽  
Vol 156 (3) ◽  
pp. 860-872 ◽  
Author(s):  
S B Binion ◽  
L S Rodkey
Keyword(s):  
Germ Line ◽  
Antibody Responses ◽  
Idiotypic Network ◽  
Paternal Origin ◽  
Cross Reactions ◽  
Network Concept ◽  
Normal Individuals ◽  
Micrococcus Lysodeikticus ◽  
The Cross ◽  
Antibody Population

Naturally induced auto-anti-idiotypic (AAI) antibody responses specific for antimicrococcal antibody idiotypes were detected in 42% of the rabbits in a family immunized with Micrococcus lysodeikticus. The natural AAI response of each rabbit recognized only a portion (11-41%) of that individual's total antimicrococcal antibody population. Cross-reactions of idiotypes were observed within the group of rabbits exhibiting natural AAI responses. Examination of the basis for the cross-reactions showed that the natural AAI antisera recognized identical idiotopes on the antimicrococcal F(ab')2 fragments from each rabbit that made an AAI response. The cross-reactive idiotopes were shown to be of paternal origin and were found in the antimicrococcal antibodies of each offspring. The data strongly support the idiotypic network concept that naturally induced AAI responses may occur routinely in outbred normal individuals as a result of antigenic stimulation. Further, the data suggest that the induction of regulatory AAI antibody responses in outbred rabbits may depend on the expression of particular germ line idiotopes.

scholarly journals Evaluation of six commercial SARS-CoV-2 serology assays detecting different antibodies for clinical testing and serosurveillance

2021 ◽  
Author(s):  
Suellen Nicholson ◽  
Theo Karapanagiotidis ◽  
Arseniy Khvorov ◽  
Celia Douros ◽  
Francesca Mordant ◽  
...  
Keyword(s):  
Cell Culture ◽  
Neutralization Test ◽  
Serological Test ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Binding Assays ◽  
Humoral Immune ◽  
A Cell

Abstract Background Serological testing for SARS-CoV-2 complements nucleic acid tests for patient diagnosis and enables monitoring of population susceptibility to inform the COVID-19 pandemic response. It is important to understand the reliability of assays with different antigen or antibody targets to detect humoral immunity after SARS-CoV-2 infection and to understand how antibody (Ab) binding assays compare to those detecting neutralizing antibody (nAb), particularly as we move into the era of vaccines. Methods We evaluated the performance of six commercially available Enzyme-linked Immunosorbent Assays (ELISAs), including a surrogate virus neutralization test (sVNT), for detection of SARS-CoV-2 immunoglobulins (IgA, IgM, IgG), total or nAb. A result subset was compared to a cell culture-based microneutralisation (MN) assay. We tested sera from patients with prior RT-PCR confirmed SARS-CoV-2 infection, pre-pandemic sera and potential cross-reactive sera from patients with other non-COVID-19 acute infections. Results For sera collected > 14 days post-symptom onset, the assay achieving the highest sensitivity was the Wantai total Ab at 100% (95% confidence interval: 94.6-100) followed by 93.1% for Euroimmun NCP-IgG, 93.1% for GenScript sVNT, 90.3% for Euroimmun S1-IgG, 88.9% for Euroimmun S1-IgA and 83.3% for Wantai IgM. Specificity for the best performing assay was 99.5% for the Wantai total Ab and for the lowest performing assay was 97.1% for sVNT (as per IFU). The Wantai Total Ab had the best agreement with MN at 98% followed by Euroimmun S1-IgA, Euro NCP-IgG and sVNT (as per IFU) with (97%, 97% and 95% respectively) and Wantai IgM having the poorest agreement at 93%. Conclusion Performance characteristics of the SARS-CoV-2 serology assays detecting different antibody types are consistent with those found in previously published reports. Evaluation of the surrogate virus neutralization test in comparison to the Ab binding assays and a cell culture-based neutralization assay showed good result correlation between all assays. However correlation between the cell-based neutralization test and some assays detecting Ab’s not specifically involved in neutralization was higher than with the sVNT. This study demonstrates the reliability of different assays to detect the humoral immune response following SARS-CoV-2 infection, which can be used to optimise serological test algorithms for assessing antibody responses post SARS-CoV-2 infection or vaccination.

Indirect Immunofluorescence Tests in Korean Hemorrhagic Fever and Epidemic (Endemic) Nephropathia: Treatment at Low pH for Removal of ‘Nonspecific’ Fluorescence in Tissues from Immunocompetent Hosts

Intervirology ◽  
1982 ◽  
Vol 18 (1-2) ◽  
pp. 38-44 ◽  
Author(s):  
Pyung-Woo Lee ◽  
Arne Svedmyr ◽  
Herbert L. Amyx ◽  
Clarence J. GíbbsJr ◽  
Carleton Gajdusek
Keyword(s):  
Indirect Immunofluorescence ◽  
Hemorrhagic Fever ◽  
Low Ph

scholarly journals Monoclonal Antibody-Based Antigen Capture Enzyme-Linked Immunosorbent Assay Reveals High Sensitivity of the Nucleocapsid Protein in Acute-Phase Sera of Severe Acute Respiratory Syndrome Patients

2005 ◽  
Vol 12 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Biao Di ◽  
Wei Hao ◽  
Yang Gao ◽  
Ming Wang ◽  
Ya-di Wang ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Acute Phase ◽  
Detection Rate ◽  
Neutralization Test ◽  
Protein Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
N Protein ◽  
Antigen Capture ◽  
Healthy Donors

ABSTRACT Accurate and timely diagnosis of severe acute respiratory syndrome coronavirus (SARS-CoV) infection is a critical step in preventing another global outbreak. In this study, 829 serum specimens were collected from 643 patients initially reported to be infected with SARS-CoV. The sera were tested for the N protein of SARS-CoV by using an antigen capture enzyme-linked immunosorbent assay (ELISA) based on monoclonal antibodies against the N protein of SARS-CoV and compared to 197 control serum samples from healthy donors and non-SARS febrile patients. The results of the N protein detection analysis were directly related to the serological analysis data. From 27 SARS patients who tested positive with the neutralization test, 100% of the 24 sera collected from 1 to 10 days after the onset of symptoms were positive for the N protein. N protein was not detected beyond day 11 in this group. The positive rates of N protein for sera collected at 1 to 5, 6 to 10, 11 to 15, and 16 to 20 days after the onset of symptoms for 414 samples from 298 serologically confirmed patients were 92.9, 69.8, 36.4, and 21.1%, respectively. For 294 sera from 248 serological test-negative patients, the rates were 25.6, 16.7, 9.3, and 0%, respectively. The N protein was not detected in 66 patients with cases of what was initially suspected to be SARS but serologically proven to be negative for SARS and in 197 serum samples from healthy donors and non-SARS febrile patients. The specificity of the assay was 100%. Furthermore, of 16 sera collected from four patients during the SARS recurrence in Guangzhou, 5 sera collected from 7 to 9 days after the onset of symptoms were positive for the N protein. N protein detection exhibited a high positive rate, 96 to 100%, between day 3 and day 5 after the onset of symptoms for 27 neutralization test-positive SARS patients and 298 serologically confirmed patients. The N protein detection rate continually decreased beginning with day 10, and N protein was not detected beyond day 19 after the onset of symptoms. In conclusion, an antigen capture ELISA reveals a high N protein detection rate in acute-phase sera of patients with SARS, which makes it useful for early diagnosis of SARS.

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