Immune response of booster doses of BBIBP-CORV vaccines against the variants of concern of SARS-CoV-2.

BACKGROUND: Booster doses for COVID-19 vaccinations are currently recommended and approved in many countries. However, we need more evidence on the immune response of individuals to booster doses of inactivated vaccines and the neutralizing effect against the variants of concerns of SARS-CoV-2. OBJECTIVE: To compare the fold reduction in antibody titers against the variants of concerns of SARS-CoV-2 between the primary doses and booster dose vaccine cohorts of inactivated BBIBP-CorV vaccine. STUDY DESIGN: In this observational study Plaque Reduction Neutralization Test (PRNT) assay was done on pooled serum samples of the recipients of primary two doses of inactivated BBIBP-CorV and on the pooled serum samples of recipients of a booster dose of inactive BBIBP-CorV. The neutralizing antibody titers against the wild (Wuhan) strain and the variants of concern (alpha, beta and delta) were compared. RESULTS: The serum sample pool from the booster cohort had high neutralizing antibody titers against the SARS-CoV-2 variants compared to the pooled serum samples of the recipients of primary two doses of inactivated BBIBP-CorV and the difference was statistically significant. The observed fold reduction in antibody titers from the serum pool of recipients of two doses of BBIBP-CorV vaccine were 3.7-fold, 14.6-fold and 10.4-fold compared to 1.8 -fold, 6.5-fold and 3.8-fold reduction against the alpha, beta and delta lineages respectively in the serum pool of recipient of a booster dose (three doses of BBIBP-CorV). CONCLUSION: Booster doses of inactive BBIBP-CORV offered better protection against the variants of concern of SARS-CoV-2.

Potential application of beta-1, 3 glucanase from an environmental isolate of Pseudomonas aeruginosa MCCB 123 in fungal DNA extraction.

Pseudomonas aeruginosa MCCB 123 was grown in a synthetic medium for beta-1,3 glucanase production. From the culture filtrate, beta-1,3 glucanase was purified with a molecular mass of 45 kDa. The enzyme was a metallozyme as its beta-1,3 glucanase activity got inhibited by the metal chelator EDTA. Optimum pH and temperature for beta-1,3 glucanase activity on laminarin was found to be 7 and 50 degrees C respectively. The MCCB 123 beta-1,3 glucanase was found to have good lytic action on a wide range of fungal isolates, and hence its application in fungal DNA extraction was evaluated. Beta-1,3 glucanase purified from the culture supernatant of P. aeruginosa MCCB 123 could be used for the extraction of fungal DNA without the addition of any other reagents generally used. Optimum pH and temperature of enzyme for fungal DNA extraction was found to be 7 and 65 degrees C respectively. This is the first report on beta-1,3 glucanase employed in fungal DNA extraction.

Alkaline protease from a non-toxigenic mangrove isolate of Vibrio sp. V26 with potential application in animal cell culture.

Vibrio sp. V26 isolated from mangrove sediment showed 98 % similarity to 16S rRNA gene of Vibrio cholerae, V. mimicus, V. albensis and uncultured clones of Vibrio. Phenotypically also it resembled both V. cholerae and V. mimicus. Serogrouping, virulence associated gene profiling, hydrophobicity, and adherence pattern clearly pointed towards the non-toxigenic nature of Vibrio sp. V26. Purification and characterization of the enzyme revealed that it was moderately thermoactive, nonhemagglutinating alkaline metalloprotease with a molecular mass of 32 kDa. The application of alkaline protease from Vibrio sp. V26 (APV26) in sub culturing cell lines (HEp-2, HeLa and RTG-2) and dissociation of animal tissue (chick embryo) for primary cell culture were investigated. The time required for dissociation of cells as well as the viable cell yield obtained by while administering APV26 and trypsin were compared. Investigations revealed that the alkaline protease of Vibrio sp. V26 has the potential to be used in animal cell culture for subculturing cell lines and dissociation of animal tissue for the development of primary cell cultures, which has not been reported earlier among metalloproteases of Vibrios.