Abstract
Very high frequencies of phosphorylcholine-specific and 10/13 idiotope-positive precursor cells were observed in spleen and liver cells polyclonally stimulated by lipopolysaccharide in BALB/c mice. These frequencies do not show any significant difference at birth, in young and adult mice, suggesting that antibody molecules analyzed arose from a single germ line heavy chain variable region gene segment. The order of magnitude of these frequencies was comparable in germ-free mice and conventionally reared BALB/c mice. Therefore, external antigenic stimulation does not seem to be involved in the establishment of antibody specificity available repertoire.