An immature B cell of an intermediate stage between the pre-B cell stage and the mature naive stage with the phenotype surface IgM-positive and CD19-positive, and are subject to the process of B cell selection. A transitional B cell migrates from the bone marrow into the peripheral circulation, and then to the spleen. [ GOC:add https://www.worldcat.org/search?q=bn%3A0781735149 http://www.ncbi.nlm.nih.gov/pubmed/22343568 http://purl.obolibrary.org/obo/go/references/0000031 http://www.ncbi.nlm.nih.gov/pubmed/12810111 ]

Synonyms: transitional stage B-lymphocyte transitional stage B lymphocyte transitional B cell transitional stage B-cell