Kihyuck Kwak

The human gut microbiota, an intricate ecosystem within the gastrointestinal tract, plays a pivotal role in health and disease. Prebiotics, non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of beneficial microorganisms, have emerged as a key modulator of this complex microbial community. This review article explores the evolution of the prebiotic concept, delineates various types of prebiotics, including fructans, galactooligo

Protective antibody responses to vaccination or infection depend on affinity maturation, a process by which high-affinity germinal center (GC) B cells are selected on the basis of their ability to bind, gather, and present antigen to T follicular helper (T_fh) cells. Here, we show that human GC B cells have intrinsically higher-affinity thresholds for both B cell antigen receptor (BCR) signaling and antigen gathering as compared with naïve B cells and that these functions are mediated

The licensed human papillomavirus (HPV) vaccines elicit type-restricted immunity but do not target cutaneous HPV types of the beta genus that are associated with non-melanoma skin cancer in immune-compromised patients, and it is unclear if these diverse types share a common mechanism of infection. Residues 11-88 of minor capsid protein L2 contain cross-protective epitopes, and vaccination with concatamers of this region derived from as many as eight alpha HPV (L2 α11-88x8) is being developed as

The demand for a vaccine for coronavirus disease 2019 (COVID-19) highlighted gaps in our understanding of the requirements for B cell responses to antigens, particularly to membrane-presented antigens, as occurs in vivo. We found that human B cell responses to membrane-presented antigens required the function of Piezo1, a plasma membrane mechanosensitive cation channel. Simply making contact with a glass probe induced calcium (Ca²⁺) fluxes in B cells that were blocked by the Piezo1 in

Multivalent vaccination via in vivo electroporation requires spatial separation of individual type L1 DNA vaccines.

B cells are the cornerstone of our body's defense system, producing precise antibodies and safeguarding immunological memory for future protection against pathogens. While we have a thorough understanding of how naïve B cells differentiate into plasma or memory B cells, the early B cell response to various antigens-whether self or foreign-remains a thrilling and evolving area of study. Advances in imaging have illuminated the molecular intricacies of B cell receptor (BCR) signaling, yet the dyna

Abstract During antibody responses to T-dependent antigens B cells undergo clonal expansion and somatic hyper-mutation in the dark zones of germinal centers (GCs) and subsequently undergo isotype switching and affinity based selection in the GC light zones. Only a small portion of B cells survive from GC reactions and differentiate into either plasma cells or memory B cells. However, the mechanism underlying selection within the GC is not fully understood. We compared the behavior of human tonsi

Human papillomavirus (HPV) vaccines have substantially reduced cervical cancer and other HPV-related diseases in high-income countries, with male vaccination addressing transmission as well as head and neck cancers. However, in low- and middle-income countries, widespread vaccination efforts are hindered by considerable costs, insufficient medical staff, and challenges in maintaining vaccine stability. Conventional microneedle vaccine production often compromises the structural integrity of viru

Abstract Protective antibody responses to vaccination or infection in humans depend on the competitive selection of high-affinity germinal-center (GC) B cells into the long-lived memory B cell compartment. Selection is determined in large part by the ability of GC B cells to gather, process and present antigen to T follicular helper T cells (TFH cells). We have shown that human GC B cells are better able to distinguish their affinity for antigen as compared to naïve B cells in the gathering and

Abstract Upon encountering pathogens, B cells within lymphoid organs enter specialized micro-environments of germinal centers (GCs). In the dark zones (DZ) of GCs, B cells proliferate and undergo somatic hypermutation, and subsequently migrate to the light zone (LZ) of the GC where selection of B cells that express the highest affinity B cell receptors (BCRs) occurs. Affinity selection is driven by the ability of BCRs to signal and extract antigen from the surfaces of follicular dendritic cells.

Abstract Unlike T cells that recognize peptide-MHC complexes, B cells recognize native antigen in both soluble and membrane-associated forms. It is well established that foreign antigen can be presented in membrane-bound form and induce B cell activation but it remains unclear how mildly autoreactive B cells retained within the repertoire after central tolerance are prevented from inducing humoral autoimmunity despite the presence of their cognate antigen in serum. Here, we demonstrate that memb