The MAR 18.5 monoclonal antibody reacts with the kappa chain of the rat immunoglobulin light chain. The κ chain is one of two types of polypeptide subunits which make up the immunoglobulin light chain. A typical antibody is composed of two immunoglobulin heavy chains and two immunoglobulin light chains. The κ chain is coded for by V (variable), J (joining) and C (constant) genes. These genes undergo V(D)J recombination to generate a diverse repertoire of immunoglobulins. This antibody is used in combination with rat anti-mouse CD19 and CD22 (clones 1D3 and Cγ34.1) to deplete B cells in vivo.

InVivoMAb anti-rat Kappa Immunoglobulin Light Chain (Clone: MAR 18.5)

Sawen, P., et al. (2016). “Mitotic History Reveals Distinct Stem Cell Populations and Their Contributions to Hematopoiesis.” Cell Rep 14(12): 2809-2818. PubMed

Homeostasis of short-lived blood cells is dependent on rapid proliferation of immature precursors. Using a conditional histone 2B-mCherry-labeling mouse model, we characterize hematopoietic stem cell (HSC) and progenitor proliferation dynamics in steady state and following several types of induced stress. HSC proliferation following HSC transplantation into lethally irradiated mice is fundamentally different not only from native hematopoiesis but also from other stress contexts. Whereas transplantation promoted sustained, long-term proliferation of HSCs, both cytokine-induced mobilization and acute depletion of selected blood cell lineages elicited very limited recruitment of HSCs to the proliferative pool. By coupling mCherry-based analysis of proliferation history with multiplex gene expression analyses on single cells, we have found that HSCs can be stratified into four distinct subtypes. These subtypes have distinct molecular signatures and differ significantly in their reconstitution potentials, showcasing the power of tracking proliferation history when resolving functional heterogeneity of HSCs.