Rapid engineering of SARS-CoV-2 therapeutic antibodies to increase breadth of neutralization including BQ.1.1, CA.3.1, CH.1.1, XBB.1.16, and XBB.1.5.

SARS-CoV-2 Omicron variant XBB.1.5 has shown extraordinary immune escape even for fully vaccinated individuals. There are currently no approved antibodies that neutralize this variant, and continued emergence of new variants puts immunocompromised and elderly patients at high risk. Rapid and cost-effective development of neutralizing antibodies is urgently needed. Starting with a single parent clone that neutralized the Wuhan-Hu-1 strain, antibody engineering was performed in iterative stages in real time as variants emerged using a proprietary technology called STage-Enhanced Maturation. An antibody panel that broadly neutralizes currently circulating Omicron variants was obtained by in vitro affinity maturation using phage display. The engineered antibodies show potent neutralization of BQ.1.1, XBB.1.16, and XBB.1.5 by surrogate virus neutralization test and pM KD affinity for all variants. Our work not only details novel therapeutic candidates but also validates a unique general strategy to create broadly neutralizing antibodies to current and future SARS-CoV-2 variants.

emm Typing of group A streptococcus clinical isolates: identification of dominant types for throat and skin isolates.

T and emm types were determined for group A streptococci isolated from patients with various infections during 1990-1999 in Toyama Prefecture, Japan. Out of 906 isolates, 872 isolates were divided into 20 T serotypes, and 34 isoltes were T nontypeable (TNT). T12, T1, and T4 were dominant among 699 throat isolates; on the other hand, T11, T28, TB3264, and TNT were dominant among 80 skin isolates. The emm types of 190 isolates were determined following specific PCR amplification and sequencing of the products. Twenty T serotypes were divided into 34 T type/emm type combinations. Thirty-four TNT isolates were divided into 14 emm types, in which emm58 was the most common (38%). Among 82 throat isolates randomly selected, predominant T types T12, T1, and T4 isolates were of the respective same numbers in emm type. T11/emm89, T28/emm28, TB3264/emm13w, and TNT/emm58 were predominant among 80 skin isolates. emm-type distribution observed in the present study was that usually reported in the western world. To our knowledge, 3 T/emm is a novel combination. These results show that emm typing allows the characterization of group A streptococci from various sources.