Expansion and functional activity of Ly‐1+ B cells upon transfer of peritoneal cells into allotype‐congenic, newborn mice

Abstract

Transfer of peritoneal cells from adult donors into newborn, allotype‐congenic mice led to colonization of the recipient mice by donor‐derived B lymphocytes expressing the Ly‐1 surface marker (Ly‐1 B cells). These cells not only persisted in the recipient mice for at least 5 months, but also increased in number. In contrast, bone marrow‐derived stem cells did not or scarcely give rise to B cells after intraperitoneal injection into congenic newborn recipients under the same experimental conditions. Approximately half of the IgM in the serum of peritoneal cell‐recipients was produced by donor‐derived Ly‐1 B cells, suggesting that high levels of serum IgM in a normal mouse are produced by this B cell subpopulation. The transferred Ly‐1 B cells were able to respond in a normal fashion to α(1 → 3)dextran, but they did not participate in thymus‐dependent and ‐independent (TI II) immune responses to the hapten (4‐hydroxy‐3‐nitrophenyl)acetyl (NP). In neither the immune response to α(1 → 3)dextran nor that to NP were we able to detect an influence of the transferred Ly‐1 B cells on the selection of the idiotypic repertoire in the recipient mice.