Physical properties of mouse peripheral lymph node cells: changes during development.

Lymphocytes from axillary and brachial lymph nodes (LN) were fractionated on the basis of electrophoretic mobility (EPM) differences by means of free-flow electrophoresis and the fractions were analysed for size distribution with a "Coulter" counter. The data were combined to form a contour map (fingerprint) representative of the various LN cell types. LN fingerprint from adult mice exhibited a distinctly bimodal pattern with a low-mobility (LM) population corresponding to B cells and a high-mobility (HM) population (80%) corresponding to T cells. These 2 populations peaked 8 to 10 electrophoretic fractions apart. In marked contrast, LN fingerprint from neonatal mice regularly presented a single peak in the HM region which was by 3 electrophoretic fractions slower than in adult mice. These neonatal HM(T) cells possessed a larger modal volume (Coulter channel no 44) than that of adult HM(T) cells (Coulter channel no 37). Moreover, these early appearing LN-T cells were found to be endowed with the same EPM as OHC-resistant thymocytes which might suggest some connection between both populations.