Intravital Imaging of Bone Marrow Microenvironment in the Mouse Calvaria and Tibia.

The complex bone marrow microenvironment or niche is an important anatomical structure responsible for hematopoiesis and providing support to the immune cells function. Being the source of immune and blood cells, the interaction of these hematopoietic stem and progenitor cells with the cellular niches regulates their ability for self-renewal, proliferation, and differentiation. Dynamic imaging not only provides spatiotemporal information of cell motility but also the morphological changes due to cell-cell interactions in the bone marrow, providing insights into the ongoing physiological activities within the tissue.

Intravital Microscopy of T-B Cell Interactions in Germinal Centers.

Dynamic imaging analyses of antigen-specific T-B interactions in germinal centers have advanced our understanding of the molecular mechanisms underlying affinity maturation and provided a wealth of information about how follicular helper T cells function in vivo. Here we describe a routine method to visualize fluorescence protein-expressing, antigen-specific T and B cells in germinal centers. The protocol for incorporating functional reporters or genetic perturbation of the T cells by retroviral transduction is also briefly described, using the FRET-based calcium reporter as an example.

Plexin B2 and Semaphorin 4C Guide T Cell Recruitment and Function in the Germinal Center.

Follicular T helper (T) cells orchestrate the germinal center (GC) response locally. T localization in GCs is controlled by chemo-guidance cues and antigen-specific adhesion. Here.

Ephrin B1-mediated repulsion and signaling control germinal center T cell territoriality and function.

Follicular T helper (T) cells orchestrate the germinal center (GC) reaction locally. Local mechanisms regulating their dynamics and helper functions are not well defined. Here we found that GC-expressed ephrin B1 (EFNB1) repulsively inhibited T cell to B cell adhesion and GC T retention by signaling through T-expressed EPHB6 receptor.

A Stochastic Model of the Germinal Center Integrating Local Antigen Competition, Individualistic T-B Interactions, and B Cell Receptor Signaling.

The germinal center (GC) reaction underlies productive humoral immunity by orchestrating competition-based affinity maturation to produce plasma cells and memory B cells. T cells are limiting in this process. How B cells integrate signals from T cells and BCRs to make fate decisions while subjected to a cyclic selection process is not clear.

T-B-cell entanglement and ICOSL-driven feed-forward regulation of germinal centre reaction.

The germinal centre (GC) reaction supports affinity-based B-cell competition and generates high-affinity bone-marrow plasma cells (BMPCs). How follicular T-helper (TFH) cells regulate GC selection is not clear. Using competitive mixed chimaera, we show here that, beyond the role in promoting TFH development, ICOSL (inducible T-cell co-stimulator ligand, also known as ICOSLG) is important for individual B cells to competitively participate in the GC reaction and to develop into BMPCs.