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1.
Article in English | MEDLINE | ID: mdl-38747849

ABSTRACT

This study aimed to provide further insight into the evolutionary dynamics of SARS-CoV-2 by analyzing the case of a 40-year-old man who had previously undergone autologous hematopoietic stem cell transplantation due to a diffuse large B-cell lymphoma. He developed a persistent SARS-CoV-2 infection lasting at least 218 days and did not manifest a humoral immune response to the virus during this follow-up period. Whole-genome sequencing and viral cultures confirmed a persistent infection with a replication-positive virus that had undergone genetic variation for at least 196 days after symptom onset.


Subject(s)
COVID-19 , Immunocompromised Host , SARS-CoV-2 , Virus Shedding , Humans , Adult , Male , COVID-19/immunology , SARS-CoV-2/immunology , SARS-CoV-2/genetics , Lymphoma, Large B-Cell, Diffuse/virology , Lymphoma, Large B-Cell, Diffuse/immunology , Hematopoietic Stem Cell Transplantation , Whole Genome Sequencing
2.
J Med Virol ; 96(2): e29471, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38353496

ABSTRACT

Human enteroviruses (EV) are the most common cause of aseptic meningitis worldwide. Data on EV viral load in cerebrospinal fluid (CSF) and related epidemiological studies are scarce in Brazil. This study investigated the influence of EV viral load on CSF parameters, as well as identifying the involved species. CSF samples were collected in 2018-2019 from 140 individuals at The Hospital das Clínicas, São Paulo. The EV viral load was determined using real-time quantitative polymerase chain reaction, while EV species were identified by 5'UTR region sequencing. Median viral load was 5.72 log10 copies/mL and did not differ by subjects' age and EV species. Pleocytosis was observed in 94.3% of cases, with the highest white blood cell (WBC) counts in younger individuals. Viral load and WBC count were correlated in children (p = 0.0172). Elevated lactate levels were observed in 60% of cases and correlated with the viral load in preteen-teenagers (p = 0.0120) and adults (p = 0.0184). Most individuals had normal total protein levels (70.7%), with higher in preteen-teenagers and adults (p < 0.0001). By sequencing, 8.2% were identified as EV species A and 91.8% as species B. Age-specific variations in CSF characteristics suggest distinct inflammatory responses in each group.


Subject(s)
Enterovirus Infections , Enterovirus , Meningitis, Aseptic , Meningitis, Viral , Child , Adult , Adolescent , Humans , Infant , Enterovirus/genetics , Meningitis, Aseptic/cerebrospinal fluid , Brazil/epidemiology , Retrospective Studies , Cerebrospinal Fluid
3.
Vaccines (Basel) ; 11(11)2023 Nov 20.
Article in English | MEDLINE | ID: mdl-38006064

ABSTRACT

Mucosal vaccination appears to be suitable to protect against SARS-CoV-2 infection. In this study, we tested an intranasal mucosal vaccine candidate for COVID-19 that consisted of a cationic liposome containing a trimeric SARS-CoV-2 spike protein and CpG-ODNs, a Toll-like receptor 9 agonist, as an adjuvant. In vitro and in vivo experiments indicated the absence of toxicity following the intranasal administration of this vaccine formulation. First, we found that subcutaneous or intranasal vaccination protected hACE-2 transgenic mice from infection with the wild-type (Wuhan) SARS-CoV-2 strain, as shown by weight loss and mortality indicators. However, when compared with subcutaneous administration, the intranasal route was more effective in the pulmonary clearance of the virus and induced higher neutralizing antibodies and anti-S IgA titers. In addition, the intranasal vaccination afforded protection against gamma, delta, and omicron virus variants of concern. Furthermore, the intranasal vaccine formulation was superior to intramuscular vaccination with a recombinant, replication-deficient chimpanzee adenovirus vector encoding the SARS-CoV-2 spike glycoprotein (Oxford/AstraZeneca) in terms of virus lung clearance and production of neutralizing antibodies in serum and bronchial alveolar lavage (BAL). Finally, the intranasal liposomal formulation boosted heterologous immunity induced by previous intramuscular vaccination with the Oxford/AstraZeneca vaccine, which was more robust than homologous immunity.

4.
Am J Reprod Immunol ; 90(5): e13788, 2023 11.
Article in English | MEDLINE | ID: mdl-37881119

ABSTRACT

PROBLEM: The association of viruses with infertility remains incompletely evaluated. METHOD OF STUDY: Vaginal secretions from 46 women seeking treatment in the Center for Reproductive Medicine and Infertility at Weill Cornell Medicine were tested for viruses by metagenomic analysis by lab personnel blinded to all clinical data. RESULTS: Torquetenovirus (TTV) was identified in 16 women, alphapapillomavirus in seven women and most were positive for bacteriophages. Twelve of the subjects were fertile and sought to freeze their oocytes for future implantation. These women were all negative for TTV. In contrast, 16 of the 34 women (47.1%) being treated for infertility were TTV-positive (p = .0035). Evaluating the women by cause of infertility, five of nine women (55.6%) whose male partner had inadequate sperm parameters and six of 14 women (42.9%) with defective ovulation were TTV positive (p = .0062 and p = .0171, respectively, vs. the fertile women). Alphapapillomavirus was identified in one (8.3%) fertile woman, five (35.7%) women with ovulation deficiency, and one (11.1%) woman with male factor infertility. These differences were not statistically significant. There were no differences in bacteriophage families or the presence of Lactobacillus phages between fertile or infertile women or between different causes of infertility. There was a negative association between TTV detection and Lactobacillus crispatus dominance in the vaginal microbiota (p = .0184), but no association between TTV detection and the presence of alphapapillomavirus or Candida species. CONCLUSION: Detection of TTV in the vagina might be a biomarker for specific causes of infertility.


Subject(s)
Infertility, Female , Infertility, Male , Lactobacillus crispatus , Torque teno virus , Male , Humans , Female , Torque teno virus/genetics , Semen , Vagina
6.
Front Med (Lausanne) ; 10: 1161091, 2023.
Article in English | MEDLINE | ID: mdl-37547599

ABSTRACT

Torquetenovirus (TTV) is a commensal virus present in many healthy individuals. Although considered to be non-pathogenic, its presence and titer have been shown to be indicative of altered immune status in individuals with chronic infections or following allogeneic transplantations. We evaluated if TTV was present in amniotic fluid (AF) at the time of in utero surgery to correct a fetal neurological defect, and whether its detection was predictive of adverse post-surgical parameters. AF was collected from 27 women by needle aspiration prior to a uterine incision. TTV titer in the AF was measured by isolation of viral DNA followed by gene amplification and analysis. The TTV genomes were further characterized and sequenced by metagenomics. Pregnancy outcome parameters were subsequently obtained by chart review. Three of the AFs (11.1%) were positive for TTV at 3.36, 4.16, and 4.19 log10 copies/mL. Analysis of their genomes revealed DNA sequences similar to previously identified TTV isolates. Mean gestational age at delivery was >2 weeks earlier (32.5 vs. 34.6 weeks) and the prevalence of respiratory distress was greater (100% vs. 20.8%) in the TTV-positive pregnancies. TTV detection in AF prior to intrauterine surgery may indicate elevated post-surgical risk for earlier delivery and newborn respiratory distress.

7.
PLoS One ; 18(8): e0291027, 2023.
Article in English | MEDLINE | ID: mdl-37651462

ABSTRACT

BACKGROUND: Redondovirus (ReDoV) is a DNA virus present in the respiratory tract of many healthy individuals. Since SARS-CoV-2, the virus responsible for COVID-19, also primarily infects the same site, we evaluated whether ReDoV was present at increased frequency in patients with COVID-19 and influenced infection parameters. METHODS: Saliva samples were collected weekly from 59 individuals with COVID-19 and from 132 controls. ReDoV was detected by polymerase chain reaction and the genotypes were identified by metagenomics. Torque Teno Virus (TTV) in these samples were previously reported. RESULTS: ReDoV was detected in saliva more frequently from COVID-19 patients (72.9%) than from controls (50.0%) (p = 0.0015). There were no associations between ReDoV detection and either continuous or intermittent SARS-CoV-2 shedding, the duration of SARS-CoV-2 detection in saliva, patients' sex or if infection was by the B1 or Gamma strain. The two ReDoV strains, Brisavirus and Vientovirus, were present in equivalent frequencies in ReDoV-positive COVID-19 patients and controls. Phylogenetic analysis suggested that the two ReDoV strains in Brazil were similar to strains previously detected on other continents. CONCLUSION: ReDoV expression in saliva is increased in males and females in Brazil with mild COVID-19 but its presence does not appear to influence properties of the SARS-CoV-2 infection.


Subject(s)
COVID-19 , SARS-CoV-2 , Female , Male , Humans , Brazil/epidemiology , Phylogeny , Saliva
8.
Front Med (Lausanne) ; 10: 1184353, 2023.
Article in English | MEDLINE | ID: mdl-37425326

ABSTRACT

Introduction: Torque teno virus (TTV) has been pointed as an endogenous marker of immune function, the objective of this study was to investigate the TTV viral load in plasma and saliva of cirrhotic individuals and correlate it with clinical characteristics. Methods: Blood, saliva, clinical data from records and laboratory tests were collected from 72 cirrhotic patients. Plasma and saliva were submitted to real-time polymerase chain reaction for quantification of TTV viral load. Results: The majority of the patients presented decompensated cirrhosis (59.7%) and 47.2% had alterations in the white blood series. TTV was identified in 28 specimens of plasma (38.8%) and in 67 specimens of saliva (93.0%), with median values of TTV copies/mL of 90.6 in plasma and 245.14 in saliva. All the patients who were positive for TTV in plasma were also positive in saliva, with both fluids having a moderately positive correlation for the presence of TTV. There was no correlation between TTV viral load, either in plasma or in saliva, and any of the variables studied. Conclusion: TTV is more frequently found and in greater amount in the saliva than in the plasma of cirrhotic patients. There was no correlation between TTV viral load and clinical parameters.

9.
Viruses ; 15(6)2023 05 29.
Article in English | MEDLINE | ID: mdl-37376568

ABSTRACT

Introduction-The dynamics of SARS-CoV-2 shedding and replication in humans remain incompletely understood. Methods-We analyzed SARS-CoV-2 shedding from multiple sites in individuals with an acute COVID-19 infection by weekly sampling for five weeks in 98 immunocompetent and 25 immunosuppressed individuals. Samples and culture supernatants were tested via RT-PCR for SARS-CoV-2 to determine viral clearance rates and in vitro replication. Results-A total of 2447 clinical specimens were evaluated, including 557 nasopharyngeal swabs, 527 saliva samples, 464 urine specimens, 437 anal swabs and 462 blood samples. The SARS-CoV-2 genome sequences at each site were classified as belonging to the B.1.128 (ancestral strain) or Gamma lineage. SARS-CoV-2 detection was highest in nasopharyngeal swabs regardless of the virus strain involved or the immune status of infected individuals. The duration of viral shedding varied between clinical specimens and individual patients. Prolonged shedding of potentially infectious virus varied from 10 days up to 191 days, and primarily occurred in immunosuppressed individuals. Virus was isolated in culture from 18 nasal swab or saliva samples collected 10 or more days after onset of disease. Conclusions-Our findings indicate that persistent SARS-CoV-2 shedding may occur in both competent or immunosuppressed individuals, at multiple clinical sites and in a minority of subjects is capable of in vitro replication.


Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , SARS-CoV-2/genetics , COVID-19 Testing , Specimen Handling , Virus Shedding , RNA, Viral/genetics
10.
Acta Cytol ; 67(4): 388-394, 2023.
Article in English | MEDLINE | ID: mdl-36682351

ABSTRACT

INTRODUCTION: The early identification of precursor lesions followed by appropriate treatment prevents development of cervical cancer and its consequences. OBJECTIVE: The present study evaluated the influence of the COVID-19 pandemic on cervical cancer screening by comparing the quantity of tests to detect cervical cellular changes performed in São Paulo state in 2019, prior to the detection of SARS-CoV-2 in Brazil, to the first (2020) and second (2021) years following its appearance. MATERIALS AND METHODS: Data from Fundação Oncocentro de São Paulo (FOSP), the agency that analyses approximately 220,000 Papanicolaou (Pap) tests annually, were reviewed. RESULTS: A median of 1,835 Pap tests were performed in 55 municipalities in 2019. This was reduced to 815 tests in 2020, a 56% decrease (p = 0.0026). In 2021, the median number was 1,745, a 53% increase over 2020 levels (p = 0.0233). The 26 municipalities with >1,000 tests in 2020 had a median reduction from 4,433 in 2019 to 2,580 in 2020 (p = 0. 0046). The 29 municipalities with <1,000 tests had a median reduction from 951 in 2019 to 554 in 2020 (p < 0.0001). There was a 44% reduction in the number of follow-up cytological evaluations from 2019 to 2020, followed by a 30% increase in the following year. However, the percentage of women with a normal finding or with any abnormality remained unchanged. The findings from a histological evaluation of women in São Paulo city indicated that the percent of cases positive for CIN-1 (p < 0.0410) and CIN-3 (p < 0.0012) increased in 2020 and 2021 as compared to 2019 levels. CONCLUSION: A reduction in testing for cervical cancer in the first year of the COVID-19 pandemic, accompanied by an elevated incidence of precancerous lesions in each of the first 2 years following its initiation, may portend a subsequent increased occurrence of cervical cancer in Brazil.


Subject(s)
COVID-19 , Uterine Cervical Dysplasia , Uterine Cervical Neoplasms , Female , Humans , Uterine Cervical Neoplasms/diagnosis , Uterine Cervical Neoplasms/epidemiology , Uterine Cervical Neoplasms/pathology , Brazil/epidemiology , Vaginal Smears , Early Detection of Cancer , Pandemics , COVID-19/epidemiology , SARS-CoV-2 , Uterine Cervical Dysplasia/pathology , Papanicolaou Test , Mass Screening
11.
Oral Dis ; 29(2): 815-826, 2023 Mar.
Article in English | MEDLINE | ID: mdl-34523191

ABSTRACT

OBJECTIVES: To characterize the oral shedding of herpes viruses in patients who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT) and investigate its relationship with clinical outcomes. MATERIALS AND METHODS: Polymerase chain reaction and enzymatic digestion were performed to identify the oral shedding of the members of the Herpesviridae family in 31 patients. The samples were collected from the oral cavity at five timestamps. RESULTS: The presence of each herpesvirus in the oral cavity was observed in 3.2%, 12.9%, 19.3%, 32.2%, 54.8% and 93.5% patients for human herpesvirus (HHV)-6A, herpes simplex virus-1, HHV-6B, cytomegalovirus (CMV), Epstein-Barr virus (EBV) and HHV-7, respectively. Oral shedding of herpes virus was not uncommon after alloHSCT. There was a statistically significant association between the EBV and CMV oral shedding at C1 and the cumulative incidence of acute graft-versus-host disease (aGVHD). The results suggested that the presence of HSV-1 at C2 was related to a relapse. The HHV-7 oral shedding at C2 suggests a possible link between relapse, progression-free survival and overall survival of the patients. CONCLUSIONS: Patients who developed aGVHD showed higher CMV and EBV shedding in the oral cavity at aplasia, suggesting modifications to the pattern of immune cell response and inflammatory microenvironment.


Subject(s)
Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Herpesviridae Infections , Herpesviridae , Mouth , Virus Shedding , Humans , DNA, Viral/analysis , Hematopoietic Stem Cell Transplantation/adverse effects , Herpesviridae/genetics , Recurrence , DNA Virus Infections , Mouth/virology
12.
Oral Dis ; 29(2): 796-802, 2023 Mar.
Article in English | MEDLINE | ID: mdl-34379873

ABSTRACT

OBJECTIVE: To assess the oral shedding and viremia of Epstein-Barr virus (EBV) in HIV-positive patients and their relationship with oral hairy leukoplakia (OHL). METHODOLOGY: A total of 94 HIV-positive patients were included in the study, in which blood and saliva samples were collected for EBV quantification. Data on gender, age, time of HIV seropositivity, combined antiretroviral therapy (cART), CD4+ T-cell counts, and HIV viral load were collected. OHL diagnosis was based on histopathological examination and EBV in situ hybridization. RESULTS: The EBV load in the 94 HIV-positive patients was higher in saliva than in blood (2.4 and 1.6, respectively), and there was a positive correlation between EBV oral shedding and viremia (p = 0.001). Twenty (21.27%) patients had OHL and also a higher EBV load in saliva (mean log10  = 3.11) compared to those who had no OHL (p = 0.045). Presence of OHL was only associated with age (p = 0.030). CONCLUSION: In HIV-positive patients, the presence of OHL was associated with EBV oral shedding but not with viremia, regardless of the amount of circulating CD4+ T cells.


Subject(s)
Epstein-Barr Virus Infections , HIV Infections , Humans , Leukoplakia, Hairy/diagnosis , Herpesvirus 4, Human , Epstein-Barr Virus Infections/complications , Viremia/complications , HIV Infections/complications , HIV Infections/drug therapy , Leukoplakia, Oral/complications
14.
Clinics (Sao Paulo) ; 77: 100068, 2022.
Article in English | MEDLINE | ID: mdl-35767900

ABSTRACT

OBJECTIVES: The aim of the present study was to evaluate if neutralizing antibody responses induced by infection with the SARS-CoV-2 strain that was dominant at the beginning of the pandemic or by the Gamma variant was effective against the Omicron variant. METHODS: Convalescent sera from 109 individuals, never exposed to a SARS-CoV-2 vaccine, who had mild or moderate symptoms not requiring hospitalization following either a documented SARS-CoV-2 ancestral strain infection or a Gamma variant infection, were assayed for in vitro neutralizing antibody activity against their original strains and the Omicron variant. RESULTS: Following an infection with the ancestral strain, 56 (93.3%), 45 (77.6%) and 1 (1.7%) serum sample were positive for neutralizing antibodies against the ancestral, Gamma variant, and Omicron variant, respectively. After infection with the Gamma variant, 43 (87.8%) and 2 (4.1%) sera were positive for neutralizing antibodies against the Gamma and Omicron variants, respectively. CONCLUSIONS: Neutralizing antibodies generated following mild or moderate infection with the SARS-CoV-2 ancestral strain or the Gamma variant are not protective against the Omicron variant.


Subject(s)
Antibodies, Neutralizing , COVID-19 , Antibodies, Viral , COVID-19/therapy , COVID-19 Vaccines , Humans , Immunization, Passive , Neutralization Tests , SARS-CoV-2 , COVID-19 Serotherapy
15.
Article in English | MEDLINE | ID: mdl-35239863

ABSTRACT

Vaccination is a fundamental tool to prevent SARS-CoV-2 infection and to limit the COVID-19 pandemic. The emergence of SARS-CoV-2 variants with multiple mutations has raised serious concerns about the ability of neutralizing antibody responses elicited by prior vaccination to effectively combat these variants. The neutralizing capacity against the Gamma, Delta and Omicron variants of sera from individuals immunized with the CoronaVac vaccine remains incompletely determined. The present study evaluated 41 health care workers at the Faculdade de Medicina of the Universidade de Sao Paulo, in Sao Paulo, Brazil, naive to previous SARS- CoV-2 infection, who were vaccinated with two doses of the CoronaVac SARS-CoV-2 vaccine 28 days apart. Neutralizing antibody levels against the Gamma, Delta, and Omicron variants were measured at 32 and 186 days after the second vaccination. We also measured neutralizing antibodies against Omicron in 34 of these individuals following a subsequent booster immunization with the Pfizer vaccine. Quantification of neutralizing antibodies was performed using the Cytopathic Effect-based Virus Neutralization test. Neutralization antibody activity against the Gamma, Delta and Omicron variants was observed in 78.0%, 65.9% and 58.5% of serum samples, respectively, obtained at a mean of 32 days after the second immunization. This decreased to 17.1%, 24.4% and 2.4% of sera having activity against Delta, Gamma and Omicron, respectively, at 186 days post-vaccination. The median neutralizing antibody titers at 32 days were 1:40, 1:20 and 1:20 against Gamma, Delta and Omicron, respectively, and decreased to an undetectable median level against all variants at the later time. A booster immunization with the Pfizer vaccine elicited neutralizing antibodies against Omicron in 85% of subjects tested 60 days after vaccination. We conclude that two doses of the CoronaVac vaccine results in limited protection of short duration against the Gamma, Delta and Omicron SARS-CoV-2 variants. A booster dose with the Pfizer vaccine induced antibody neutralizing activity against Omicron in most patients which was measurable 60 days after the booster.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Neutralizing , Antibodies, Viral , Brazil , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Pandemics , Vaccination
16.
PLoS One ; 17(1): e0262672, 2022.
Article in English | MEDLINE | ID: mdl-35051215

ABSTRACT

Torquetenovirus (TTV) is a nonpathogenic endogenous virus whose abundance varies with the extent of immune system activation. We determined if the TTV titer in the vagina of pregnant women was associated with vaginal microbiota composition and levels of compounds in vaginal secretions. Vaginal TTV and microbiota composition in 494 second trimester pregnant women were identified by gene amplification and analysis. Vaginal matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMP) and lactic acid isomers were measured by ELISA. Dominance was defined as the relative abundance of a specific bacterium or species at >50% of the total number of bacteria identified. Clinical data were obtained by chart review. The median log10 TTV titer was lowest when Lactobacillus species other than L. iners were dominant (<1.0) as compared to when L. iners (4.1, p = 0.0001), bacteria other than lactobacilli (4.5, p = 0.0016) or no bacterium (4.7, p = 0.0009) dominated. The TTV titer was inversely proportional to L. crispatus abundance (p<0.0001) and directly proportional to levels of G. vaginalis (p = 0.0008) and L. iners (p = 0.0010). The TTV titer was proportional to TIMP-1, TIMP-2, MMP-8 and MMP-9 abundance (p≤0.0002) and inversely proportional to the level of D-lactic acid (p = 0.0024). We conclude that the association between variations in the TTV titer and the relative abundance of specific bacterial species and vaginal compounds indicates that local changes in immune status likely influence vaginal fluid composition.


Subject(s)
Microbiota/physiology , Torque teno virus/isolation & purification , Vagina/microbiology , Adult , Female , Humans , Pregnancy , Pregnant Women , Vagina/virology
18.
Article in English | LILACS-Express | LILACS | ID: biblio-1360801

ABSTRACT

ABSTRACT Vaccination is a fundamental tool to prevent SARS-CoV-2 infection and to limit the COVID-19 pandemic. The emergence of SARS-CoV-2 variants with multiple mutations has raised serious concerns about the ability of neutralizing antibody responses elicited by prior vaccination to effectively combat these variants. The neutralizing capacity against the Gamma, Delta and Omicron variants of sera from individuals immunized with the CoronaVac vaccine remains incompletely determined. The present study evaluated 41 health care workers at the Faculdade de Medicina of the Universidade de Sao Paulo, in Sao Paulo, Brazil, naive to previous SARS- CoV-2 infection, who were vaccinated with two doses of the CoronaVac SARS-CoV-2 vaccine 28 days apart. Neutralizing antibody levels against the Gamma, Delta, and Omicron variants were measured at 32 and 186 days after the second vaccination. We also measured neutralizing antibodies against Omicron in 34 of these individuals following a subsequent booster immunization with the Pfizer vaccine. Quantification of neutralizing antibodies was performed using the Cytopathic Effect-based Virus Neutralization test. Neutralization antibody activity against the Gamma, Delta and Omicron variants was observed in 78.0%, 65.9% and 58.5% of serum samples, respectively, obtained at a mean of 32 days after the second immunization. This decreased to 17.1%, 24.4% and 2.4% of sera having activity against Delta, Gamma and Omicron, respectively, at 186 days post-vaccination. The median neutralizing antibody titers at 32 days were 1:40, 1:20 and 1:20 against Gamma, Delta and Omicron, respectively, and decreased to an undetectable median level against all variants at the later time. A booster immunization with the Pfizer vaccine elicited neutralizing antibodies against Omicron in 85% of subjects tested 60 days after vaccination. We conclude that two doses of the CoronaVac vaccine results in limited protection of short duration against the Gamma, Delta and Omicron SARS-CoV-2 variants. A booster dose with the Pfizer vaccine induced antibody neutralizing activity against Omicron in most patients which was measurable 60 days after the booster.

19.
Clinics ; 77: 100068, 2022. tab
Article in English | LILACS-Express | LILACS | ID: biblio-1394284

ABSTRACT

Abstract Objectives: The aim of the present study was to evaluate if neutralizing antibody responses induced by infection with the SARS-CoV-2 strain that was dominant at the beginning of the pandemic or by the Gamma variant was effective against the Omicron variant. Methods: Convalescent sera from 109 individuals, never exposed to a SARS-CoV-2 vaccine, who had mild or moderate symptoms not requiring hospitalization following either a documented SARS-CoV-2 ancestral strain infection or a Gamma variant infection, were assayed for in vitro neutralizing antibody activity against their original strains and the Omicron variant. Results: Following an infection with the ancestral strain, 56 (93.3%), 45 (77.6%) and 1 (1.7%) serum sample were positive for neutralizing antibodies against the ancestral, Gamma variant, and Omicron variant, respectively. After infection with the Gamma variant, 43 (87.8%) and 2 (4.1%) sera were positive for neutralizing antibodies against the Gamma and Omicron variants, respectively. Conclusions: Neutralizing antibodies generated following mild or moderate infection with the SARS-CoV-2 ancestral strain or the Gamma variant are not protective against the Omicron variant. HIGHLIGHTS Individuals previously infected with SARS-CoV-2 ancestral strain do not develop neutralizing antibodies against the Omicron variant. Omicron variant escapes immune response after SARS CoV-2 previous infection with the SARS CoV-2 Gamma variant. Individuals previously infected with SARS-CoV-2 ancestral strain or with SARS-CoV-2 Gamma variant will likely have little protection if subsequently exposed to the Omicron variant.

20.
Clinics (Sao Paulo) ; 76: e3548, 2021.
Article in English | MEDLINE | ID: mdl-34878034

ABSTRACT

OBJECTIVES: In this preliminary study we investigated cellular and humoral immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in blood samples from 14 recovered coronavirus disease 2019 (COVID-19) patients and compared them to those in samples from 12 uninfected/unvaccinated volunteers. METHODS: Cellular immunity was assessed by intracellular detection of IFN-γ in CD3+ T lymphocytes after stimulation with SARS-CoV-2 spike (S1), nucleocapsid (NC), or receptor-binding domain (RBD) recombinant proteins or overlapping peptide pools covering the sequence of SARS-CoV-2 spike, membrane and nucleocapsid regions. The humoral response was examined by ELISAs and/or chemiluminescence assays for the presence of serum IgG antibodies directed to SARS-CoV-2 proteins. RESULTS: We observed differences between humoral and cellular immune profiles in response to stimulation with the same proteins. Assays of IgG antibodies directed to SARS-CoV-2 NC, RBD and S1/S2 recombinant proteins were able to differentiate convalescent from uninfected/unvaccinated groups. Cellular immune responses to SARS-CoV-2 protein stimuli did not exhibit a specific response, as T cells from both individuals with no history of contact with SARS-CoV-2 and from recovered donors were able to produce IFN-γ. CONCLUSIONS: Determination of the cellular immune response to stimulation with a pool of SARS-CoV-2 peptides but not with SARS-CoV-2 proteins is able to distinguish convalescent individuals from unexposed individuals. Regarding the humoral immune response, the screening for serum IgG antibodies directed to SARS-CoV-2 proteins has been shown to be specific for the response of recovered individuals.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Humans , Immunity, Humoral , Recombinant Proteins , Spike Glycoprotein, Coronavirus
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