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1.
J Immunol ; 208(6): 1500-1508, 2022 03 15.
Article in English | MEDLINE | ID: covidwho-1715878

ABSTRACT

Oral fluids offer a noninvasive sampling method for the detection of Abs. Quantification of IgA and IgG Abs in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG Abs against the prefusion-stabilized form of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein expressed in suspension-adapted HEK-293 cells. Normalization against total Ab isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 prepandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA, 95.5%; IgG, 89.7%) without compromising specificity (IgA, 99%; IgG, 97%). No cross-reactivity with endemic coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/ml and 0.30 ng/ml, respectively. Salivary IgA and IgG Abs were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary Ab titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 wk in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.


Subject(s)
Antibodies, Viral/metabolism , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Immunoglobulin A/metabolism , Immunoglobulin G/metabolism , SARS-CoV-2/physiology , Saliva/metabolism , Adolescent , Adult , Aged , Asymptomatic Diseases , Child , Child, Preschool , Disease Progression , Enzyme-Linked Immunosorbent Assay/standards , Female , Humans , Infant , Male , Mass Screening , Middle Aged , Pandemics , Reference Standards , Sensitivity and Specificity , Severity of Illness Index , Young Adult
2.
J Infect Dis ; 225(6): 947-956, 2022 03 15.
Article in English | MEDLINE | ID: covidwho-1704045

ABSTRACT

The unprecedented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has called for substantial investigations into the capacity of the human immune system to protect against reinfection and keep pace with the evolution of SARS-CoV-2. We evaluated the magnitude and durability of the SARS-CoV-2-specific antibody responses against parental WA-1 SARS-CoV-2 receptor-binding domain (RBD) and a representative variant of concern (VoC) RBD using antibodies from 2 antibody compartments: long-lived plasma cell-derived plasma antibodies and antibodies encoded by SARS-CoV-2-specific memory B cells (MBCs). Thirty-five participants naturally infected with SARS-CoV-2 were evaluated; although only 25 of 35 participants had VoC RBD-reactive plasma antibodies, 34 of 35 (97%) participants had VoC RBD-reactive MBC-derived antibodies. Our finding that 97% of previously infected individuals have MBCs specific for variant RBDs provides reason for optimism regarding the capacity of vaccination, prior infection, and/or both, to elicit immunity with the capacity to limit disease severity and transmission of VoCs as they arise and circulate.


Subject(s)
COVID-19 , SARS-CoV-2/genetics , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Humans , Severity of Illness Index , Spike Glycoprotein, Coronavirus
3.
Case Rep Hematol ; 2022: 6831640, 2022.
Article in English | MEDLINE | ID: covidwho-1666501

ABSTRACT

Individuals with chronic lymphocytic leukemia (CLL) have significant immune disfunction, often further disrupted by treatment. While currently available COVID-19 vaccinations are highly effective in immunocompetent individuals, they are often poorly immunogenic in CLL patients. It is important to understand the role a heterologous boost would have in patients who did not respond to the initial two-dose mRNA vaccine series. SARS-CoV-2 specific immune responses, including antibodies and memory B-cells, CD4 and CD8 T-cells were assessed prior to vaccination, as well as postinitial vaccination series and post-third dose in two subjects. One subject seroconverted, had RBD-specific memory B-cells and spike-specific CD4 T-cells while the other did not. Both subjects had a spike-specific CD8 T-cell response after the original mRNA vaccination series that was further boosted after the third dose or remained stable. The results of this study, however small, are especially promising to CLL individuals who did not seroconvert following the initial mRNA vaccination series.

5.
J Infect Dis ; 225(6): 947-956, 2022 03 15.
Article in English | MEDLINE | ID: covidwho-1550554

ABSTRACT

The unprecedented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has called for substantial investigations into the capacity of the human immune system to protect against reinfection and keep pace with the evolution of SARS-CoV-2. We evaluated the magnitude and durability of the SARS-CoV-2-specific antibody responses against parental WA-1 SARS-CoV-2 receptor-binding domain (RBD) and a representative variant of concern (VoC) RBD using antibodies from 2 antibody compartments: long-lived plasma cell-derived plasma antibodies and antibodies encoded by SARS-CoV-2-specific memory B cells (MBCs). Thirty-five participants naturally infected with SARS-CoV-2 were evaluated; although only 25 of 35 participants had VoC RBD-reactive plasma antibodies, 34 of 35 (97%) participants had VoC RBD-reactive MBC-derived antibodies. Our finding that 97% of previously infected individuals have MBCs specific for variant RBDs provides reason for optimism regarding the capacity of vaccination, prior infection, and/or both, to elicit immunity with the capacity to limit disease severity and transmission of VoCs as they arise and circulate.


Subject(s)
COVID-19 , SARS-CoV-2/genetics , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Humans , Severity of Illness Index , Spike Glycoprotein, Coronavirus
6.
Nat Commun ; 12(1): 5135, 2021 08 26.
Article in English | MEDLINE | ID: covidwho-1376198

ABSTRACT

SARS-CoV-2 and its variants continue to infect hundreds of thousands every day despite the rollout of effective vaccines. Therefore, it is essential to understand the levels of protection that these vaccines provide in the face of emerging variants. Here, we report two demographically balanced cohorts of BNT162b2 vaccine recipients and COVID-19 patients, from which we evaluate neutralizing antibody titers against SARS-CoV-2 as well as the B.1.1.7 (alpha) and B.1.351 (beta) variants. We show that both B.1.1.7 and B.1.351 are less well neutralized by serum from vaccinated individuals, and that B.1.351, but not B.1.1.7, is less well neutralized by convalescent serum. We also find that the levels of variant-specific anti-spike antibodies are proportional to neutralizing activities. Together, our results demonstrate the escape of the emerging SARS-CoV-2 variants from neutralization by serum antibodies, which may lead to reduced protection from re-infection or increased risk of vaccine breakthrough.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/blood , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/administration & dosage , Child , Child, Preschool , Cohort Studies , Female , Humans , Infant , Male , Middle Aged , Neutralization Tests , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Young Adult
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