A transitional stage B cell that migrates from the bone marrow into the peripheral circulation, and finally to the spleen. This cell type has the phenotype surface IgM-positive, surface IgD-negative, CD21-negative, CD23-negative, and CD62L-negative, and CD93-positive. This cell type has also been described as IgM-high, CD19-positive, B220-positive, AA4-positive, and CD23-negative. [ GOC:tfm https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2193793 http://www.ncbi.nlm.nih.gov/pubmed/12810111 GOC:msz http://purl.obolibrary.org/obo/go/references/0000031 GOC:dsd ]

Synonyms: T1 B lymphocyte T1 B-lymphocyte T1 B-cell transitional stage 1 B cell