title: Functional avidity: a measure to predict the efficacy of effector T cells?
abstract: The functional avidity is determined by exposing T-cell populations in vitro to different amounts of cognate antigen. T-cells with high functional avidity respond to low antigen doses. This in vitro measure is thought to correlate well with the in vivo effector capacity of T-cells. We here present the multifaceted factors determining and influencing the functional avidity of T-cells. We outline how changes in the functional avidity can occur over the course of an infection. This process, known as avidity maturation, can occur despite the fact that T-cells express a fixed TCR. Furthermore, examples are provided illustrating the importance of generating T-cell populations that exhibit a high functional avidity when responding to an infection or tumors. Furthermore, we discuss whether criteria based on which we evaluate an effective T-cell response to acute infections can also be applied to chronic infections such as HIV. Finally, we also focus on observations that high-avidity T-cells show higher signs of exhaustion and facilitate the emergence of virus escape variants. The review summarizes our current understanding of how this may occur as well as how T-cells of different functional avidity contribute to antiviral and anti-tumor immunity. Enhancing our knowledge in this field is relevant for tumor immunotherapy and vaccines design.
authors.affiliation: Divisions of Immunology and Allergy, Department of Medicine, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland.
authors.forename: Selena
authors.initials: S
authors.lastname: Viganò
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Utzschneider
authors.forename: Matthieu
authors.initials: M
authors.lastname: Perreau
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pantaleo
authors.forename: Dietmar
authors.initials: D
authors.lastname: Zehn
authors.forename: Alexandre
authors.initials: A
authors.lastname: Harari
mesh_terms: D000818:Animals; D006801:Humans; D007239:Infections / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D011948:Receptors, Antigen, T-Cell