TransGLYCIT™ in a Study on Antibody Characterization
Scientists from the Wistar Institute in Philadelphia and collaborators have studied the IgG N-glycan structures and inflammatory aging markers of people living with and without HIV to determine a potential structure-function relationship. In this study, TransGLYCIT was used to generate anti-HIV antibodies with defined N-glycan structures to study Fc-mediated immune activities in vitro.
Chronic human immunodeficiency virus (HIV) infection is linked to increased premature aging and inflammation-associated comorbidities despite disease suppression using antiretroviral therapy. While the pathophysiological mechanisms behind these events are poorly understood, a better comprehension of these mechanisms is required for the development of biomarkers and eventually for preventative onset measures The Fc N-glycan structures of circulating IgG have been associated with aging and both systemic and chronic inflammation and thus, the authors hypothesized that changes in the Fc N-glycan structures impact the aging and inflammation-associated comorbidities of people living with HIV. To address this, the N-glycan structures and a variety of markers of people living with and without HIV were studied showing that HIV-associated IgG N-glycan alterations correlates with elevated levels of inflammatory markers, chronological age and pro-aging, severity of comorbidities, and glycan-degrading enzymes linked to senescence.
To further investigate the mechanism behind these events in vitro, TransGLYCIT was used to generate anti-HIV IgG with defined Fc N-glycan structures. TransGLYCIT is a platform technology that enables efficient and site-specific human IgG glycan remodeling. With TransGLYCIT, antibodies with defined and homogenous glycoforms are generated using fast and robust enzymatic workflows.
Figure 1. Schematic overview of the TransGLYCIT workflow.
The broadly neutralizing antibody 10-1074, currently in clinical studies as an anti-HIV treatment, was used as a model antibody, and remodeled to carry one of the G0F, G0, G2F and G2 glycoforms. The glycoforms were selected to represent the fucosylated, agalactosylated, and terminally galactosylated groups also studied on the population level. Initially, the antigen binding of the antibodies was confirmed to demonstrate that the antigen binding is unaffected by TransGLYCIT remodeling. The different variants were then used to investigate the impact of fucosylation, agalactosylation, and terminal galactosylation on anti-HIV ADCC activity. The activity was measured using a cell-based reporter gene bioassay where the cells can be infected by HIV to associate the ADCC activity to HIV infection. The results displayed that the fucosylated and agalactosylated antibodies had lower anti-HIV ADCC activities and higher levels of HIV p24-infected cells than the afucosylated and terminally galacosylated ones, further supporting the in vivo data.
In summary, the authors have demonstrated correlations between IgG N-glycan structure and pro-aging and inflammation in people living with HIV and shown TransGLYCIT to be a valuable tool for mechanistic investigations using functional in vitro assays.
Reference
Giron et al., 2024. Immunoglobulin G N-glycan markers of accelerated biological aging during chronic HIV infection. Nature Communications
TransGLYCIT™ – Transglycosylation of IgG