**Bryce Chackerian \* and David S. Peabody**

Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA; dpeabody@salud.unm.edu

**\*** Correspondence: bchackerian@salud.unm.edu

Received: 9 December 2019; Accepted: 4 January 2020; Published: 7 January 2020

**Abstract:** The induction of long-lasting, high-titer antibody responses is critical to the efficacy of many vaccines. The ability to produce durable antibody responses is governed by the generation of the terminally differentiated antibody-secreting B cells known as long-lived plasma cells (LLPCs). Once induced, LLPCs likely persist for decades, providing long-term protection against infection. The factors that control the generation of this important class of B cells are beginning to emerge. In particular, antigens with highly dense, multivalent structures are especially effective. Here we describe some pathogens for which the induction of long-lived antibodies is particularly important, and discuss the basis for the extraordinary ability of multivalent antigens to drive differentiation of naïve B cells to LLPCs.

**Keywords:** long-lived plasma cells; antibodies; multivalency; virus-like particles
