FC-Engineering-EI

ABSTRACT Novel vaccination and therapeutic strategies are urgently needed to mitigate the tuberculosis (TB) epidemic. While extensive efforts have focused on potentiating cell-mediated immunity to control Mycobacterium tuberculosis (Mtb) infection, less effort has been invested in exploiting the humoral immune system to combat Mtb. Emerging data point to a role for antibodies in microbial control of Mtb, however the precise mechanism(s) of this control remain incompletely understood. Here we took an antibody Fc-engineering approach to determine whether Fc-modifications could improve the ability of antibodies to restrict Mtb, and to define Fc-mediated mechanism(s) antibodies leverage for this restriction. Using an antibody specific to the capsular polysaccharide α-glucan, we engineered a panel of Fc variants to augment or dampen select antibody effector functions, rationally building antibodies with enhanced capacity to promote Mtb restriction in a human whole blood model of infection. Surprisingly, several restrictive Fc-engineered antibodies drove Mtb control in a neutrophil, not monocyte, dependent manner. Using single cell RNA sequencing, we show that an Fc-engineered antibody with restrictive activity promotes neutrophil survival and expression of cell intrinsic antimicrobial programs. These data provide a roadmap for exploiting Fc-engineered antibodies as a novel class of TB therapeutics able to harness the protective functions of neutrophils to achieve disease control.