1.Knowledge, Attitude, and Practices Assessment of Unvaccinated Adult In-patients Regarding COVID-19 Vaccination in a Tertiary Hospital in Nueva Vizcaya, Philippines: A Cross-sectional Study.
Charity May B. Pazziwagan ; Emmeline B. Borillo
Acta Medica Philippina 2026;60(3):78-87
OBJECTIVES
his quantitative cross-sectional study aimed to determine the level of knowledge, attitude, and practices
regarding COVID-19 vaccination of unvaccinated adult patients admitted at Region II Trauma and Medical Center
(R2TMC). This may help determine the knowledge gap regarding COVID-19 vaccination, address it, and to achieve
the goal to vaccinate all eligible Filipinos. Furthermore, this may also be a springboard for future researches and
management regarding novel infections needing new vaccinations.
Collected data from the sample size of 197 using the formula for finite population with 95% confidence
level, population proportion of 50%, population size of 400, allowing 5% margin of error were summarized in a
Microsoft excel database and tables, then were analyzed using Jamovi version 2.6.22 software. Frequency, mean,
and standard deviation were calculated to measure the knowledge, attitude, and practices; Pearson correlation and
Kendall’s Tau b correlation for its relationship.
There is moderate level of knowledge (MS: 9.80-11.8), a positive attitude (MR: 2.35-2.60), and good preventive
practices (MS: 12.00-13.00) regarding SARS-CoV-2 (COVID-19) vaccination among the unvaccinated adult in-patients
of R2TMC post-pandemic. Knowledge, attitudes, and practices statistically differed (pCONCLUSION
There is a significant correlation among the knowledge of the respondents about COVID-19 vaccination,
their attitude towards it, and their practices, implying that promoting preventive behaviors toward COVID-19 would
require promoting both knowledge and efficacy beliefs among the public.
Human ; Bacteria ; Male ; Female ; Adult: 25-44 Yrs Old ; Middle Aged: 45-64 Yrs Old ; Wounds And Injuries ; Population Density ; Cross-sectional Studies ; Forecasting ; Sars-cov-2 ; Sars Virus ; Covid-19
2.External ocular manifestations among patients diagnosed with Coronavirus disease 2019 in a referral center in the Philippines.
Alyssa Louise B. Pejana-Paulino ; Aramis B. Torrefranca Jr. ; Nilo Vincent DG. Florcruz ; Ma. Dominga B. Padilla
Acta Medica Philippina 2026;60(1):69-77
BACKGROUND AND OBJECTIVES
The global pandemic caused by Coronavirus Disease 2019 (COVID-19) has affected millions, with growing evidence of the potential role of ocular tissues in viral transmission. At the time of writing, local data regarding the phenomenon was limited. This study investigated external ocular manifestations in patients with COVID-19 at a referral center in the Philippines, examined correlations between demographics, systemic manifestations, and laboratory results with ocular manifestations, and determined their timing relative to systemic symptoms.
METHODSThis single-center, descriptive cross-sectional study was carried out from December 8 to 18, 2020 at the adult COVID-19 wards of the Philippine General Hospital involving 72 participants. Data collection involved relevant clinical history taking and performing gross eye examination. The prevalence of ocular manifestations was described with 95% confidence intervals. Correlations between ocular manifestations and quantitative variables were analyzed with point-biserial correlation, and associations with qualitative variables were tested using chi-square or Fisher’s exact tests.
RESULTSAmong participants, 31.9% presented with ocular manifestations with foreign body sensation as the most prevalent ocular symptom (11.1%) and conjunctival hyperemia as the most prevalent ocular finding (19.4%). The median age of patients with ocular manifestations was 41 years old with a higher prevalence in the male population (73.9%, CI=95%, p=0.001). No significant correlation was observed between presence of external ocular manifestations and the different systemic and ocular co-morbidities as well as with COVID-19 clinical classification. Among those who experienced symptoms, majority (29.2%) of the patients experienced systemic symptoms prior to the onset of ocular symptoms. Ocular complaints may present as the sole manifestation (13.9%). Several laboratory parameters were measured and only temperature and AST levels showed a low positive correlation with the presence of ocular manifestations.
CONCLUSIONOcular manifestations occur in roughly one third of patients with COVID-19 based on this study population. With some individuals presenting with ocular signs or symptoms as the initial and sole manifestation, healthcare practitioners must exercise caution and remain vigilant in managing patients who present as such. At the time of writing, this is the first local study investigating the different external ocular manifestations in patients with COVID-19. There is a need to pursue more robust studies and conduct more local investigations which will guide both ophthalmologists and other practitioners in strengthening existing guidelines regarding precautionary practices, clinical diagnosis, and management of COVID-19 patients.
Human ; Sars-cov-2 ; Covid-19 ; Philippines ; Adult ; Association ; Classification ; Collection ; Confidence Intervals ; Coronavirus ; Cross-sectional Studies ; Data Collection ; Demography ; Diagnosis ; Disease ; Exercise ; Eye ; Foreign Bodies ; History ; Hospitals ; Hospitals, General ; Hyperemia ; Laboratories ; Male ; Morbidity ; Ophthalmologists ; Pandemics ; Patients ; Population ; Prevalence ; Referral And Consultation ; Role ; Sensation ; Temperature ; Time ; Tissues ; Volition ; World Health Organization ; Writing
3.Genomic variant surveillance of SARS-CoV-2 positive specimens using a direct PCR product sequencing surveillance (DPPSS) method.
Nicole Ann L. Tuberon ; Francisco M. Heralde III ; Catherine C. Reportoso ; Arturo L. Gaitano III ; Wilmar Jun O. Elopre ; Kim Claudette J. Fernandez
Acta Medica Philippina 2026;60(1):57-68
BACKGROUND AND OBJECTIVE
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as the causative agent of COVID-19 has significantly challenged the public health landscape in late 2019. After almost 3 years of the first ever SARS-CoV-2 case, the World Health Organization (WHO) declared the end of this global health emergency in May 2023. Although, despite the subsequent drop of COVID-19 cases, the SARS-CoV-2 infection still exhibited multiple waves of infection, primarily attributed to the appearance of new variants. Five of these variants have been classified as Variants of Concern (VOC): Alpha, Beta, Gamma, Delta, and the most recent, Omicron. Therefore, the development of methods for the timely and accurate detection of viral variants remains fundamental, ensuring an ongoing and effective response to the disease. This study aims to evaluate the feasibility of the application of an in-house approach in genomic surveillance for the detection of SARS-CoV-2 variants using in silico designed primers.
METHODSThe primers used for the study were particularly designed based on conserved regions of certain genes in the virus, targeting distinct mutations found in known variants of SARS-CoV-2. Viral RNA extracts from nasopharyngeal samples (n=14) were subjected to quantitative and qualitative tests (Nanodrop and AGE). Selected samples were then analyzed by RT-PCR and amplicons were submitted for sequencing. Sequence alignment analysis was carried out to identify the prevailing COVID-19 variant present in the sample population.
RESULTSThe study findings demonstrated that the in-house method was able to successfully amplify conserved sequences (spike, envelope, membrane, ORF1ab) and enabled identification of the circulating SARS-CoV-2 variant among the samples. Majority of the samples were identified as Omicron variant. Three out of four designed primers effectively bound into the conserved sequence of target genes present in the sample, revealing the specific SARSCoV-2 variant. The detected mutations characterized for Omicron found in the identified lineages included K417N, S477N, and P681H which were also identified as mutations of interest. Furthermore, identification of the B.1.448 lineage which was not classified in any known variant also provided the potential of the developed in-house method in detecting unknown variants of COVID-19.
CONCLUSIONAmong the five VOCs, Omicron is the most prevalent and dominant variant. The in-house direct PCR product sequencing surveillance (DPPSS) method provided an alternative platform for SAR-CoV-2 variant analysis which is accessible and affordable than the conventional diagnostic surveillance methods and the whole genome sequencing. Further evaluation and improvements on the oligonucleotide primers may offer significant contribution to the development of a specific and direct PCRbased detection of new emerging COVID-19 variants.
Sars-cov-2 ; Polymerase Chain Reaction ; Dna Primers ; Oligonucleotide Primers ; Computer Simulation ; Conserved Sequence ; Coronavirus ; Covid-19 ; Disease ; Emergencies ; Evaluation Studies As Topic ; Genes ; Genome ; Global Health ; Health ; Identification (psychology) ; Infection ; Infections ; Membranes ; Methods ; Mutation ; Oligonucleotides ; Organizations ; Population ; Public Health ; Rna ; Rna, Viral ; Sars Virus ; Sequence Alignment ; Severe Acute Respiratory Syndrome ; Syndrome ; Viruses ; Whole Genome Sequencing ; World Health Organization
4.Neutralization of SARS-CoV-2 spike pseudotyped viruses using postbiotic preparations from Lactiplantibacillus plantarum BS25.
Joshua Angelo Hermida Mandanas ; Day Yu-Chao ; Leslie Michelle M. Dalmacio
Acta Medica Philippina 2026;60(7):58-75
BACKGROUND
Despite the presence of SARS-CoV-2 antivirals, namely, remdesivir, nirmatrelvir and toremifene, these drugs entail adverse effects and limited effectiveness. Thus, development of a safer alternative is imperative, and likely candidates include the cell-free supernatant (CFS) and protein fractions from Lactiplantibacillus plantarum strains. These postbiotics have known antiviral properties primarily mediated by plantaricins and enhanced by organic acids.
OBJECTIVESThe study determined the in silico mechanism of plantaricins against the receptor-binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2), as well as compared the in vitro activities of the L. plantarum BS25 CFS, semi-purified and crude protein fractions, against the SARS-CoV-2 pseudotyped viruses (nCoV-S-EGFP) expressing the spike of wild-type (wt) Wuhan strain, Omicron BA.1 and BA.4/5 variants. Further, this study determined the metabolome of the strain BS25 CFS.
METHODSA quasi-experimental approach was utilized in the study. Plantaricins were screened for safety in silico, followed by molecular docking with RBD and ACE2. Using a cell culture model, two-fold dilutions of the CFS and fractions were tested for cytotoxicity and microneutralization against the pseudoviruses. Mass spectrometry was utilized for the metabolomics.
RESULTSPlantaricins interact stably with RBD than ACE2 which were mediated by hydrogen, hydrophobic and covalent bonds. The activities of the CFS and fractions were substantially higher against the nCoV-SEGFP BA.4/5 variant. The 1:8 dilution of CFS entailed no cytotoxicity and displayed higher activities than toremifene. Metabolomics has identified a relatively abundant putative peptide, followed by organic acids and cyclic peptides.
CONCLUSIONPlantaricins can prevent SARS-CoV-2 entry by interacting with key RBD mutations or with intrinsically disordered RBD residues. The cationic and hydrophobic RBD mutations in the BA.4/5 variant may facilitate interactions with the putative peptide from the CFS and fractions, hence the observed potent activities. These findings can be used as basis for the development of an alternative antiviral targeting the RBD of live or pseudotyped SARS-CoV-2 variants.
Sars-cov-2
5.Association of SARS-COV 2 real-time PCR Cycle threshold (Ct) values with the clinical and laboratory profiles of confirmed COVID-19 patients admitted in tertiary infectious disease Hospital in Manila: A retrospective study
Edith S. Tria ; Joy P. Calayo ; Zita R. Dela merced ; Joel T. duque ; Cayel Jurist C. Garong ; John Robert C. Medina ; Geraldine B. Dayrit
Acta Medica Philippina 2025;59(Early Access 2025):1-12
BACKGROUND AND OBJECTIVES
COVID-19 has quickly spread over the world and became an unprecedented burden on health care systems. COVID-19 diagnosis necessitates the use of precise testing methods such as RT-PCR. This method is generally reported as positive or negative, however, studies have shown its semi-quantitative capability through Ct values. This study determined an association that exists between the Ct values, clinical features, and laboratory findings among COVID-19 patients admitted in a tertiary infectious disease hospital in Manila, Philippines. This attempts to further explore the utility of RT-PCR in disease severity classification and diagnosis.
METHODSThis was an observational retrospective study that utilized a purposive sampling method, wherein patients were selected based on the DOH case definition of confirmed COVID-19, and were stratified according to disease severity. Baseline laboratory data of the patients were gathered from medical records covering the period of June 2021 to January 2022 using a Data Collection Form. Chi-square test was used to measure the degree of association between the groups and categorical variables. Regression Analysis was used to identify predictors for certain variables. SPSS Statistics for Windows, Version 25.0 was utilized for the statistical analysis.
RESULTSThe total WBC, neutrophil, lymphocyte and monocyte counts, serum urea, LDH, CRP and PTT were found to be predictors of COVID-19 severity. There was no significant difference observed between the disease severity and the patient’s clinical outcome. All routine laboratory tests that were taken at baseline (ORF Gene, N-Gene, Hematocrit, White Blood Cells, Neutrophil, Lymphocyte, Monocyte, Platelet Count, Urea, Creatinine, SGPT, SGOT, Na, K, LDH, Ferritin, C Reactive Protein, Procalcitonin, D-Dimer, PT, PTT) were not significant predictors of the clinical outcome. Although WBC, neutrophil, lymphocyte, and monocyte count, urea, LDH, CRP, and PTT were predictors of disease severity. The study also reported that the odds of having severe to critical disease increases by 20.6% for every one unit increase in neutrophil count, and 17.4% for every one unit increase in lymphocyte count. Among the laboratory parameters, neutrophil count (p=0.010654063) and urea (p= 0.04149874 have direct relationship with the N gene Ct values while Orf gene Ct Values have direct relationship with lymphocyte count (p=0.01269027). Similarly, regression showed that as monocyte count, creatinine levels, and serum ferritin decrease, Ct values increase. Sex was found to not be a significant predictor of disease severity and clinical outcome. There was also no significant difference observed between the disease severity and the patient’s clinical outcome.
CONCLUSIONThe study showed that the Ct values for both ORF and N genes were not significant predictors of both disease severity and clinical outcome. However, ORF gene Ct values have direct relationship with lymphocyte counts while N gene Ct values have direct correlation with neutrophil count and urea levels. Similarly, monocyte, creatinine, and ferritin are negatively correlated with Ct values. It is important to monitor the patient’s laboratory biomarkers in order to determine the proper course of treatment and management for each case.
Human ; Sars-cov-2 ; Covid-19
6.External ocular manifestations among patients diagnosed with Coronavirus disease 2019 in a referral center in the Philippines
Alyssa Louise B. Pejana-paulino ; Aramis B. Torrefranca jr. ; Nilo Vincent Dg. Florcruz ; Ma. Dominga B. Padilla
Acta Medica Philippina 2025;59(Early Access 2025):1-9
BACKGROUND AND OBJECTIVES
The global pandemic caused by Coronavirus Disease 2019 (COVID-19) has affected millions, with growing evidence of the potential role of ocular tissues in viral transmission. At the time of writing, local data regarding the phenomenon was limited. This study investigated external ocular manifestations in patients with COVID-19 at a referral center in the Philippines, examined correlations between demographics, systemic manifestations, and laboratory results with ocular manifestations, and determined their timing relative to systemic symptoms.
METHODSThis single-center, descriptive cross-sectional study was carried out from December 8 to 18, 2020 at the adult COVID-19 wards of the Philippine General Hospital involving 72 participants. Data collection involved relevant clinical history taking and performing gross eye examination. The prevalence of ocular manifestations was described with 95% confidence intervals. Correlations between ocular manifestations and quantitative variables were analyzed with point-biserial correlation, and associations with qualitative variables were tested using chi-square or Fisher’s exact tests.
RESULTSAmong participants, 31.9% presented with ocular manifestations with foreign body sensation as the most prevalent ocular symptom (11.1%) and conjunctival hyperemia as the most prevalent ocular finding (19.4%). The median age of patients with ocular manifestations was 41 years old with a higher prevalence in the male population (73.9%, CI=95%, p=0.001). No significant correlation was observed between presence of external ocular manifestations and the different systemic and ocular co-morbidities as well as with COVID-19 clinical classification. Among those who experienced symptoms, majority (29.2%) of the patients experienced systemic symptoms prior to the onset of ocular symptoms. Ocular complaints may present as the sole manifestation (13.9%). Several laboratory parameters were measured and only temperature and AST levels showed a low positive correlation with the presence of ocular manifestations.
CONCLUSIONOcular manifestations occur in roughly one third of patients with COVID-19 based on this study population. With some individuals presenting with ocular signs or symptoms as the initial and sole manifestation, healthcare practitioners must exercise caution and remain vigilant in managing patients who present as such. At the time of writing, this is the first local study investigating the different external ocular manifestations in patients with COVID-19. There is a need to pursue more robust studies and conduct more local investigations which will guide both ophthalmologists and other practitioners in strengthening existing guidelines regarding precautionary practices, clinical diagnosis, and management of COVID-19 patients.
Human ; Sars-cov-2 ; Covid-19 ; Philippines
7.Genomic variant surveillance of SARS-CoV-2 positive specimens using a direct PCR product sequencing surveillance (DPPSS) method
Nicole Ann L. Tuberon ; Francisco M. Heralde III ; Catherine C. Reportoso ; Arturo L. Gaitano III ; Wilmar Jun O. Elopre ; Kim Claudette J. Fernandez
Acta Medica Philippina 2025;59(Early Access 2025):1-12
BACKGROUND AND OBJECTIVE
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as the causative agent of COVID-19 has significantly challenged the public health landscape in late 2019. After almost 3 years of the first ever SARS-CoV-2 case, the World Health Organization (WHO) declared the end of this global health emergency in May 2023. Although, despite the subsequent drop of COVID-19 cases, the SARS-CoV-2 infection still exhibited multiple waves of infection, primarily attributed to the appearance of new variants. Five of these variants have been classified as Variants of Concern (VOC): Alpha, Beta, Gamma, Delta, and the most recent, Omicron. Therefore, the development of methods for the timely and accurate detection of viral variants remains fundamental, ensuring an ongoing and effective response to the disease. This study aims to evaluate the feasibility of the application of an in-house approach in genomic surveillance for the detection of SARS-CoV-2 variants using in silico designed primers.
METHODSThe primers used for the study were particularly designed based on conserved regions of certain genes in the virus, targeting distinct mutations found in known variants of SARS-CoV-2. Viral RNA extracts from nasopharyngeal samples (n=14) were subjected to quantitative and qualitative tests (Nanodrop and AGE). Selected samples were then analyzed by RT-PCR and amplicons were submitted for sequencing. Sequence alignment analysis was carried out to identify the prevailing COVID-19 variant present in the sample population.
RESULTSThe study findings demonstrated that the in-house method was able to successfully amplify conserved sequences (spike, envelope, membrane, ORF1ab) and enabled identification of the circulating SARS-CoV-2 variant among the samples. Majority of the samples were identified as Omicron variant. Three out of four designed primers effectively bound into the conserved sequence of target genes present in the sample, revealing the specific SARSCoV-2 variant. The detected mutations characterized for Omicron found in the identified lineages included K417N, S477N, and P681H which were also identified as mutations of interest. Furthermore, identification of the B.1.448 lineage which was not classified in any known variant also provided the potential of the developed in-house method in detecting unknown variants of COVID-19.
CONCLUSIONAmong the five VOCs, Omicron is the most prevalent and dominant variant. The in-house direct PCR product sequencing surveillance (DPPSS) method provided an alternative platform for SAR-CoV-2 variant analysis which is accessible and affordable than the conventional diagnostic surveillance methods and the whole genome sequencing. Further evaluation and improvements on the oligonucleotide primers may offer significant contribution to the development of a specific and direct PCRbased detection of new emerging COVID-19 variants.
Sars-cov-2 ; Polymerase Chain Reaction ; Dna Primers ; Oligonucleotide Primers
8.Risk of COVID-19 outcomes among healthcare workers: Findings from the Philippine CORONA retrospective cohort study
Adrian I. Espiritu ; Carl Froilan D. Leochico ; Isabella E. Supnet ; Emilio Q. Villanueva III ; Marie Charmaine C. Sy ; Veeda Michelle M. Anlacan ; Roland Dominic G. Jamora
Acta Medica Philippina 2025;59(2):25-32
OBJECTIVES
While many healthcare workers (HCWs) contracted COVID-19 during the pandemic, more information is needed to fully understand the potential for adverse health effects in this population segment. The aim of the present study is to examine the association between healthcare worker status and neurologic and clinical outcomes in COVID-19 infected inpatients.
METHODSUsing the nationwide database provided by the retrospective cohort Philippine CORONA study, we extracted relevant data and performed a secondary analysis primarily focusing on the presentation and outcomes of healthcare workers. Propensity score matching in a 3:1 ratio was performed to match HCWs and non-HCWs. We performed multiple logistic and Cox regression analyses to determine the relationship between HCWs and COVID-19 clinical outcomes.
RESULTSWe included 3,362 patients infected with COVID-19; of which, 854 were HCWs. Among the HCWs, a total of 31 (3.63%) and 45 (5.27%) had the primary outcomes of in-hospital mortality and respiratory failure, respectively. For both overall and 3:1 propensity-matched cohorts, being an HCW significantly decreased the odds of the following outcomes: severe/critical COVID-19 at nadir; in-hospital mortality; respiratory failure; intensive care unit admission; and hospital stay >14 days.
CONCLUSIONWe found that being an HCW is not associated with worse neurologic and clinical outcomes among patients hospitalized for COVID-19.
Human ; Health Personnel ; Covid-19 ; Sars-cov-2 ; Cohort Studies
9.Construction of a human anti-SARS-CoV-2 scFv library and identification of broad-spectrum neutralizing antibodies.
Huimin YIN ; Hai LYU ; Ying CHI ; Jingxian LIU ; Yongjun JIAO ; Pingmin WEI
Chinese Journal of Cellular and Molecular Immunology 2025;41(2):154-160
Objective To construct a library of human-derived anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) single-chain variable fragments (scFv) and screen for broad-spectrum neutralizing antibodies to identify candidate molecules for the development of diagnostic and therapeutic agents. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from the peripheral blood of patients who had recovered from novel coronavirus infection. Total RNA was extracted from these PBMCs and reverse transcribed into cDNA, which was used as a template for constructing a human anti-SARS-CoV-2 scFv library. Phage display technology was used to screen for scFv antibodies specific to the SARS-CoV-2 S protein. Full-length IgG antibodies were synthesized through sequence analysis and human IgG expression, and their binding capacity and neutralizing activity against SARS-CoV-2 were evaluated. Results A human-derived scFv antibody library against SARS-CoV-2 with a capacity of 1.56×107 CFU was successfully constructed. Two specific scFv antibodies were screened from this library and expressed as full-length IgG antibodies (IgG-A10 and IgG-G6). IgG-A10 exhibited strong neutralizing activity against both the original SARS-CoV-2 strain (WT) and the XBB subvariant of the Omicron variant. However, the neutralizing activity of this antibody against the JN.1 sub lineage of the Omicron BA.2.86 variant was moderate. Conclusion This study has successfully constructed a human anti-SARS-CoV-2 scFv antibody library from the peripheral blood of recovered patients, and screened and expressed anti-SARS-CoV-2 IgG antibodies with neutralizing activity, laying a foundation for the prevention, diagnosis, and treatment of SARS-CoV-2 infection.
Humans
;
Single-Chain Antibodies/genetics*
;
SARS-CoV-2/immunology*
;
COVID-19/immunology*
;
Immunoglobulin G/genetics*
;
Antibodies, Viral/genetics*
;
Peptide Library
;
Spike Glycoprotein, Coronavirus/immunology*
;
Antibodies, Neutralizing/immunology*
;
Leukocytes, Mononuclear/immunology*
;
Broadly Neutralizing Antibodies/immunology*
10.Prokaryotic expression, purification and immunogenicity of SARS-CoV-2 omicron variant nucleocapsid protein.
Zewen TU ; Quansheng WANG ; Shiguo LIU ; Haosen LIU ; Chunyan ZENG ; Juanjuan XIE ; Mingzhi LI ; Jingcai LI ; Min WANG ; Shiqi WENG ; Lumei KANG ; Lingbao KONG
Chinese Journal of Cellular and Molecular Immunology 2025;41(8):735-743
Objective The study aims to investigate the immunological functions of the nucleocapsid (N) protein of the novel coronavirus Omicron (BA.1, BA.2) and evaluate the differences among different N proteins of mutant strains in immunogenicity. Methods By aligning sequences, the mutation sites of the Omicron (BA.1, BA.2) N protein relative to prototype strain of the novel coronavirus (Wuhan-Hu-1) were determined. The pET-28a-N-Wuhan-Hu-1 plasmid was used as template to construct pET-28a-BA.1/BA.2-N through single point mutation or homologous recombination. The three kinds of N protein were expressed in prokaryotic system, purified through Ni-NTA affinity chromatography, and then immunized into mice. The titer and reactivity of the polyclonal antibody, as well as the expression level of IL-1β and IFN-γ in mouse spleen cells, were detected using indirect ELISA and Western blot assay. Results The constructed prokaryotic expression plasmids were successfully used to express the Wuhan-Hu-1 N, BA.1 N, and BA.2 N proteins in E.coli BL21(DE3) at 37 DegreesCelsius for 4 hours. The indirect ELISA test showed that the titers of polyclonal antibody prepared by three N proteins were all 1:51 200. All three N proteins can increase the expression of IFN-γ and IL-1β cytokines, but the effect of Omicron N protein in activing two cytokines was more obvious than that of Wuhan-Hu-1 N protein. Conclusion The study obtained three new coronavirus N proteins and polyclonal antibodies, and confirmed that mutations in the amino acid sites of the N protein can affect its immunogenicity. This provides a basis for developing rapid diagnostic methods targeting N protein of different novel coronavirus variants.
Animals
;
Mice
;
SARS-CoV-2/genetics*
;
Coronavirus Nucleocapsid Proteins/immunology*
;
Nucleocapsid Proteins/isolation & purification*
;
COVID-19/immunology*
;
Antibodies, Viral/immunology*
;
Mice, Inbred BALB C
;
Interferon-gamma/metabolism*
;
Interleukin-1beta/metabolism*
;
Female
;
Escherichia coli/metabolism*
;
Mutation
;
Humans


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