Use of Chlamydial Elementary Bodies as Probes to Isolate Pathogen-Specific Human Monoclonal Antibodies.

Chlamydia trachomatis is one of the most prevalent sexually transmitted infectious agents in the world and the leading cause of infectious blindness. The role of antibodies in the prevention and clearance of infection is still not fully understood, but the analysis of the immunoglobulin response to novel vaccine candidates is an important part of many of these studies. In this chapter, we describe a novel method to identify and isolate Chlamydia-specific memory B cells by fluorescence-activated cell sorting (FACS) using fluorescently labeled whole bacteria from cryopreserved human PBMC samples. This method allows for live single cells to be sorted for cell culture, in vitro assays, single-cell RNA sequencing, and cloning of paired heavy and light chains for recombinant monoclonal antibody production.