985 ONTOGENY OF B CELL FUNCTION IN HUMAN BONE MARROW

Abstract

The development of the bone marrow B cell compartment was studied using marrow samples from adult and pediatric donors <1 yr old. The frequency, isotype commitment and secretory characteristics of B cells able to secrete immunoglobulin (Ig) was determined in limiting dilution cultures of 10-10,000 EBV infected and non-infected marrow cells. Ig secreting clones were detected by ELISA of supernates after 3-4 wk of culture. In striking contrast to adult marrow, pediatric marrow contained only small numbers of spontaneously Ig producing cells, most Ig producers were committed to IgM-production and most were EBV transformables:

These differences approximate patterns of Ig-isotype expression in serum. However, the presence of similar numbers of B cells committed and able to produce IgG or IgA at a time when only IgG is expressed in serum suggests that isotype specific regulatory mechanisms, rather than ‘B cell immaturity’ direct the late expression of serum IgA. These regulatory mechanisms are reminiscent of IgA deficiency and may be bypassed in limiting dilution cultures.

This work was supported by the MRC and NCI of Canada.

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD