Seroconversion and Abundance of IgG Antibodies against S1-RBD of SARS-CoV-2 and Neutralizing Activity in the Chilean Population.

COVID-19 is a pandemic caused by SARS-CoV-2. In Chile, half a million people have been infected and more than 16,000 have died from COVID-19. As part of the clinical trial NCT04384588, we quantified IgG against S1-RBD of SARS-CoV-2 (anti-RBD) in recovered people in Santiago and evaluated their suitability as COVID-19 convalescent plasma donors. ELISA and a luminescent SARS-CoV-2 pseudotype were used for IgG and neutralizing antibody quantification. 72.9% of the convalescent population (468 of 639) showed seroconversion (5-55 µg/mL anti-RBD IgG) and were suitable candidates for plasma donation. Analysis by gender, age, and days after symptom offset did not show significant differences. Neutralizing activity correlated with an increased concentration of anti-RBD IgG (p < 0.0001) and showed a high variability between donors. We confirmed that the majority of the Chilean patients have developed anti-SARS-CoV-2 antibodies. The quantification of anti-RBD IgG in convalescent plasma donors is necessary to increase the detection of neutralizing antibodies.

Interference in immediate spatial memory: shifts of spatial attention or central-executive involvement?

Interference in serial spatial memory was investigated in six experiments. Experiment 1 replicated Experiment 2 by Smyth and Scholey (1994) in showing that listening to tones that originated from different directions interfered with spatial memory. Experiment 2 showed, however, that the effect of mere listening was not observed when this was the only interference condition experienced by the subject. In Experiment 3, a binary pitch discrimination task performed on spatially separated tones impaired recall performance to the same extent as did left-right decisions. The same disrupting effect was also observed when the tones were presented from the same direction in the pitch discrimination task (Experiment 4) as well as in a binary loudness discrimination task (Experiment 5). Finally, repeating heard words did not interfere, whereas pitch discrimination performed on these same words disrupted recall (Experiment 6). It is argued that the disrupting effects reflect not a specifically spatial interference, but a central executive involvement in the rehearsal process in serial spatial memory.

[Local and systemic antibody response after vaccination with 3 different types of vaccines against influenza. II. Neuraminidase inhibiting antibodies (author's transl)]. / Zur lokalen und systemischen Immunantwort nach Influenza-Schutzimpfung mit drei verschiedenen Vakzinetypen. II. Neuraminidasehemmende Antikörper.

Three types of inactivated bivalent influenza vaccines containing the A/Victoria/3/75 (A-Component) and B/Hongkong/8/73 (B-Component) antigens either as aluminium salt adsorbed whole virus (AlorbatTM, "A") and split virus (Begrivac STM, "B") or as fluid subunit (SandovacTM, "S") products were given to immunological homogeneous study groups of adults and children. The immune response was compared between the groups on the basis of systemic and local neuraminidase inhibiting (NI) antibody induction 4 weeks after vaccination. In evaluation of the serologic results the sea and nasal washings were tested in the ESSEN-NIT with use of the A/Eq(eq1)-VIC (N 2) recombinant antigen and the B/Hong kong/8/73 strain. The number of individuals (adults plus children) evaluated ranged from 33 to 35 per vaccine. The percentages of persons greater than or equal to 16 years old showing a significant (1.5 x, or greater) response to the A-component were 100%, 96% and 90%, respectively for the vaccine "A", "S" and "B"; the values for the B-component were 70%, 79% and 74%, respectively. The observed conversion rates in children ranged 70% to 100%. Local antibody formation was less pronounced, the percentages of significant conversions were scattered over a wide range from 13% to 80% yielding slightly better responses in children than adults. Taken altogether, the results of the trial indicate that the 3 vaccines studied induced appreciable concentrations of systemic antibodies to the neuraminidase antigen without significant differences between the vaccine types. This potency of the influenza vaccines to induce high titers of NI antibodies thus provides another marker for their immunogenicity and conceivably for their efficacy.