Molecular basis of SARS-CoV-2 Omicron variant evasion from shared neutralizing antibody response

Understanding the molecular features of neutralizing epitopes is important for developing vaccines/therapeutics against emerging SARS-CoV-2 variants. We describe three monoclonal antibodies (mAbs) generated from COVID-19 recovered individuals during the first wave of the pandemic in India. These mAbs had publicly shared near germline gene usage and potently neutralized Alpha and Delta, poorly neutralized Beta, and failed to neutralize Omicron BA.1 SARS-CoV-2 variants. Structural analysis of these mAbs in complex with trimeric spike protein showed that all three mAbs bivalently bind spike with two mAbs targeting class 1 and one targeting a class 4 receptor binding domain epitope. The immunogenetic makeup, structure, and function of these mAbs revealed specific molecular interactions associated with the potent multi-variant binding/neutralization efficacy. This knowledge shows how mutational combinations can affect the binding or neutralization of an antibody, which in turn relates to the efficacy of immune responses to emerging SARS-CoV-2 escape variants.

Molecular basis of SARS-CoV-2 Omicron variant evasion from shared neutralizing antibody response

A detailed understanding of the molecular features of the neutralizing epitopes developed by viral escape mutants is important for predicting and developing vaccines or therapeutic antibodies against continuously emerging SARS-CoV-2 variants. Here, we report three human monoclonal antibodies (mAbs) generated from COVID-19 recovered individuals during first wave of pandemic in India. These mAbs had publicly shared near germline gene usage and potently neutralized Alpha and Delta, but poorly neutralized Beta and completely failed to neutralize Omicron BA.1 SARS-CoV-2 variants. Structural analysis of these three mAbs in complex with trimeric spike protein showed that all three mAbs are involved in bivalent spike binding with two mAbs targeting class-1 and one targeting class-4 Receptor Binding Domain (RBD) epitope. Comparison of immunogenetic makeup, structure, and function of these three mAbs with our recently reported class-3 RBD binding mAb that potently neutralized all SARS-CoV-2 variants revealed precise antibody footprint, specific molecular interactions associated with the most potent multi-variant binding / neutralization efficacy. This knowledge has timely significance for understanding how a combination of certain mutations affect the binding or neutralization of an antibody and thus have implications for predicting structural features of emerging SARS-CoV-2 escape variants and to develop vaccines or therapeutic antibodies against these.

Molecular basis of SARS-CoV-2 Omicron variant evasion from shared neutralizing antibody response

A detailed understanding of the molecular features of the neutralizing epitopes developed by viral escape mutants is important for predicting and developing vaccines or therapeutic antibodies against continuously emerging SARS-CoV-2 variants. Here, we report three human monoclonal antibodies (mAbs) generated from COVID-19 recovered individuals during first wave of pandemic in India. These mAbs had publicly shared near germline gene usage and potently neutralized Alpha and Delta, but poorly neutralized Beta and completely failed to neutralize Omicron BA.1 SARS-CoV-2 variants. Structural analysis of these three mAbs in complex with trimeric spike protein showed that all three mAbs are involved in bivalent spike binding with two mAbs targeting class-1 and one targeting class-4 Receptor Binding Domain (RBD) epitope. Comparison of immunogenetic makeup, structure, and function of these three mAbs with our recently reported class-3 RBD binding mAb that potently neutralized all SARS-CoV-2 variants revealed precise antibody footprint, specific molecular interactions associated with the most potent multi-variant binding / neutralization efficacy. This knowledge has timely significance for understanding how a combination of certain mutations affect the binding or neutralization of an antibody and thus have implications for predicting structural features of emerging SARS-CoV-2 escape variants and to develop vaccines or therapeutic antibodies against these.

The influence of vitamin E on capsule formation and contracture around silicone implants

An attempt was made to determine if the tissue response to surgical trauma and foreign body stimulus (silicone implants) could be altered using vitamin E in rats. The animals were divided into four groups: Group A served as controls, Group B were treated by intramuscular vitamin E, Group C were treated topically with vitamin E around the prosthesis, and Group D were treated topically with croton oil around the prosthesis. The animals in each group were killed at 2 week, 1 month, and 3 months intervals. The intraprosthetic pressure in each prosthesis was recorded using a strain gauge transducer. The capsules were then removed and examined histologically using a light microscope and the thickness of pseudocapsules was measured with an ocular micrometer. In Group B significantly thinner pseudocapsules were observed at 2 weeks, but there was no comparable difference either in thickness or degree of contracture (as measured by intraprosthetic pressures) between Groups A and B at 2 months and 3 months. In Group C, the pseudocapsules were significantly thicker at all tested periods and showed noticeable contracture at 3 months. In group D the pseudocapsules were thickest and cellular infiltrate more marked than in the other groups.

Results of simple scar excision and layered repair with elevation in facial scars

Spreading tension across scars is curtailed when revised by simple scar excision and layered repair with elevation of wound margins. The procedure has reduced the width and leveled the scar to the surrounding skin in all our patients. Hairline scars result more frequently in scars of less width preoperatively.

The study of hematomas in 500 consecutive face lifts

Our incidence of hematoma in 500 consecutive face lifts was 2.6 percent, of which 1.6 percent were severe enough to need evacuation. This incidence of hematoma correlated well with the blood pressures of patients on admission; when the pressure was above 150/100 mm Hg on admission, hematoma occurred 2.6 times more frequently than in normotensive patients. Our premedication regime and hypotensive therapy was effective in reducing preoperative hypertension to normotensive levels in most, but not all, patients. However, this reduction of the postoperative blood pressure to normal levels did not prevent hematoma formation entirely.

A study of the critical bacterial inoculum to cause a stimulus to wound healing

Results of previous work have shown that wounds infected with gram-negative bacteria may be stronger than uninfected wounds. The inoculum in these studies was about 2 X 10(7) organisms. Laparotomy wounds were swabbed with inocula of from 10(2) to 10(9) organisms, Escherichia coli. Only with inocula of 10(6) or greater were all parts of all wounds infected by gross inspection. All wounds inoculated with 10(7) organisms, or more, were significantly stronger than the wounds of the control group on the 14th day. A smaller inoculum--10(3) to 10(6)--also resulted in stronger wounds, but not consistently so.