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1.
Immunology ; 167(2): 275-285, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35758860

RESUMEN

As there are limited data of the immunogenicity of the Sinopharm/BBIBP-CorV in different populations, antibody responses against different SARS-CoV-2 variants of concern and T cell responses, we investigated the immunogenicity of the vaccine, in individuals in Sri Lanka. SARS-CoV-2-specific antibodies were measured in 282 individuals who were seronegative at baseline, and ACE2 receptor blocking antibodies, antibodies to the receptor-binding domain (RBD) of the wild-type (WT), alpha, beta and delta variants, ex vivo and cultured IFNγ ELISpot assays, intracellular cytokine secretion assays and B cell ELISpot assays were carried out in a sub cohort of the vaccinees at 4 and 6 weeks (2 weeks after the second dose). Ninety-five percent of the vaccinees seroconverted, although the seroconversion rates were significantly lower (p < 0.001) in individuals >60 years (93.3%) compared to those who were 20-39 years (98.9%); 81.25% had ACE2 receptor blocking antibodies at 6 weeks, and there was no difference in these antibody titres in vaccine sera compared to convalescent sera (p = 0.44). Vaccinees had significantly less (p < 0.0001) antibodies to the RBD of WT and alpha, although there was no difference in antibodies to the RBD of beta and delta compared to convalescent sera; 27.7% of 46.4% of vaccinees had ex vivo IFNγ and cultured ELISpot responses respectively, and IFNγ and CD107a responses were detected by flow cytometry. Sinopharm/BBIBP-CorV appeared to induce a similar level of antibody responses against ACE2 receptor, delta and beta as seen following natural infection.


Asunto(s)
COVID-19 , SARS-CoV-2 , Enzima Convertidora de Angiotensina 2 , Anticuerpos Bloqueadores , Anticuerpos Antivirales , Formación de Anticuerpos , COVID-19/terapia , Citocinas , Humanos , Inmunización Pasiva , Receptores Opioides delta , Sri Lanka/epidemiología , Sueroterapia para COVID-19
2.
Sci Rep ; 12(1): 1727, 2022 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-35110645

RESUMEN

As the first dose of Gam-COVID-Vac, is currently used as a single dose vaccine in some countries, we investigated the immunogenicity of this at 4 weeks (327 naïve individuals). 88.7% seroconverted, with significantly lower seroconversion rates in those over 60 years (p = 0.004) and significantly lower than previously seen with AZD1222 (p = 0.018). 82.6% developed ACE2 receptor blocking antibodies, although levels were significantly lower than following natural infection (p = 0.0009) and a single dose of AZD1222 (p < 0.0001). Similar titres of antibodies were observed to the receptor binding domain of WT, B.1.1.7 and B.1.617.2 compared to AZD1222, while the levels for B.1.351 were significantly higher (p = 0.006) for Gam-COVID-Vac. 30% developed ex vivo IFNγ ELISpot responses (significantly lower than AZD1222), and high frequency of CD107a expressing T cells along with memory B cell responses. Although single dose of Gam-COVID-Vac was highly immunogenic, administration of a second dose is likely to be beneficial.


Asunto(s)
Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Vacunas contra la COVID-19/administración & dosificación , COVID-19/prevención & control , ChAdOx1 nCoV-19/administración & dosificación , Inmunización , Inmunogenicidad Vacunal , SARS-CoV-2/inmunología , Vacunas Sintéticas/administración & dosificación , Adulto , Anciano , Anciano de 80 o más Años , Enzima Convertidora de Angiotensina 2/inmunología , Biomarcadores/sangre , COVID-19/inmunología , COVID-19/virología , Vacunas contra la COVID-19/inmunología , ChAdOx1 nCoV-19/inmunología , Femenino , Humanos , Interferón gamma/metabolismo , Linfocitos/inmunología , Linfocitos/metabolismo , Linfocitos/virología , Masculino , Persona de Mediana Edad , Seroconversión , Factores de Tiempo , Resultado del Tratamiento , Vacunas Sintéticas/inmunología , Adulto Joven
3.
medRxiv ; 2021 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-34704105

RESUMEN

BACKGROUND: To determine the kinetics and persistence of immune responses following the Sinopharm/BBIBP-CorV, we investigated immune responses in a cohort of Sri Lankan individuals. METHODS: SARS-CoV-2 specific total antibodies were measured in 20-to-39 year (n=61), 40-to-59-year and those >60 years of age (n=22) by ELISA, 12 weeks after the second dose of the vaccine. ACE2 receptor blocking antibodies (ACE2R-Ab), antibodies to the receptor binding domain (RBD) of the ancestral virus (WT) and variants of concern, were measured in a sub cohort. T cell responses and memory B cell responses were assessed by ELISpot assays. RESULTS: 193/203 (95.07%) of individuals had detectable SARS-CoV-2 specific total antibodies, while 67/110 (60.9%) had ACE2R-Ab. 14.3% to 16.7% individuals in the 20 to 39 age groups had detectable antibodies to the RBD of the WT and VOC, while the positivity rates of those >60 years of age was <10%. 14/49 (28.6%) had IFN γ ELISpot responses to overlapping peptides of the spike protein, while memory B cell responses were detected in 9/20 to the S1 recombinant protein. The total antibody levels and ACE2R-Ab declined after 2 to 12 weeks from the second dose, while ex vivo T cell responses remained unchanged. The decline in ACE2R-Ab levels was significant among the 40 to 59 (p=0.0007) and ≥60 (p=0.005) age groups. CONCLUSIONS: Antibody responses declined in all age groups, especially in those >60 years, while T cell responses persisted. The effect of waning of immunity on hospitalization and severe disease should be assessed by long term efficacy studies.

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