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61). Until July 2021, the BBIBP-CorV (76.3%) and Sinovac CoronaVac (20.5%) were the predominant vaccines injection in Shenzhen, seropositive rate of inactive SRAR-CoV-2 vaccines exceeded 97% after inoculation. The NTAb generated by Sinovac CoronaVac with the schedule of 0-56 days was found significantly lower than that by BBIBP-CorV (P < 0.001).

The follow-up of NTAb changes in a cohort and the dynamic variation of NTAb in real world disclosed steep downward by almost three times for NTAb level occurred at three months post twice vaccinations. The seropositive ratio was at least 50% over 6 months. Polysaccharide polymer : SARS-CoV-2 neutralizing antibodies assay show excellent analytical and clinical performances, and a high correlation with neutralizing activity. Anti-epidemic measures and the urgent trial of SARS-CoV-2 vaccine was calling for means to evaluate T-independent immune function in the rat.testing, studies were undertaken to adapt assays routinely used to evaluate immune function in mice so that immune function could likewise be evaluated in collaborative projects employing toxicant-treated rats. Contrary to previous reports in the literature, Type III pneumococcal polysaccharide (S3) was immunogenic in rats. Specific antibody responses to S3 were demonstrated in two strains of rats following immunization by either the subcutaneous (sc) or intraperitoneal (ip) route with purified S3, with S3 contained in polyvalent pneumococcal polysaccharide vaccine (pneumovax), or with heat-killed Type III Streptococcus pneumoniae.

Dose-response studies demonstrated that the optimal immunizing dose in Sprague-Dawley or Fischer rats was 25 micrograms S3. Reimmunization with S3 on d 21 did not produce an anamnestic response, and the kinetic data were consistent with S3 being a thymus-independent (T-independent) antigen in the rat. In contrast to our previous studies in the mouse, concurrent sc or ip injections of pertussis vaccine did not modify the response to S3 in rats. Sprague-Dawley rats acquired the capacity to respond immunologically to S3 between 24 and 31 d of age. In mature animals, sex had no effect on the ability to respond to S3. The utility of this model as a means of characterize toxicant-induced immune dysfunction was demonstrated using the prototype immunotoxicant cyclo-phosphamide.GUINEA-PIGS DURING SIMULTANEOUS ACTIVE AND PASSIVE IMMUNIZATION.

with the RTS,S malaria vaccine in young children.among young children at risk. However, vaccine efficacy is modest and short-lived. Antibodies play the major role in vaccine-induced immunity, but knowledge on the induction, decay, and determinants of antibody function is limited, especially among children. Antibodies that promote opsonic phagocytosis and other cellular functions appear to be important contributors to RTS,S immunity. METHODS: We studied a phase IIb trial of RTS,S/AS02 conducted in young children in malaria-endemic regions of Mozambique. Polysucrose 400 evaluated the induction of antibodies targeting the circumsporozoite protein (CSP, vaccine antigen) that interact with Fcγ-receptors (FcRγs) and promote phagocytosis (neutrophils, monocytes, THP-1 cells), antibody-dependent respiratory burst (ADRB) by neutrophils, and natural killer (NK) cell activity, as well as the temporal kinetics of responses over 5 years of follow-up (ClinicalTrials.

gov registry number NCT00197041). RESULTS: RTS,S vaccination induced CSP-specific IgG with FcγRIIa and FcγRIII binding activity and promoted phagocytosis by neutrophils, THP-1 monocytes, and primary human monocytes, neutrophil ADRB activity, and NK cell activation. Responses were highly heterogenous among children, and the magnitude of neutrophil phagocytosis by antibodies was relatively modest, which may reflect modest vaccine efficacy. Induction of functional antibodies was lower among children with higher malaria exposure. Functional antibody magnitude and the functional activity of antibodies largely declined within a year post-vaccination, and decay were highest in the first 6 months, consistent with the decline in vaccine efficacy over that time. Decay rates varied for different antibody parameters and decay was slower for neutrophil phagocytosis.