The distribution of surface immunoglobulin (Ig) on mouse bone marrow derived (B) lymphocytes was studied by examining freeze etched replicas of cells labeled with monovalent (Fab) anti Ig antibody. Spleen lymphocytes were treated with fluorescein isothiocyanate (FITC) conjugates of Fab anti Ig, followed by a ferritin conjugate of Fab anti FITC. Freeze etched replicas revealed the label in small clusters (2 to 20 ferritin grains each) and networks with bare membrane in between. The same pattern was observed in cells labeled at 4°C and 20°C, using FITC Fab anti Ig with molar F:P ratios of 8 and 1, and in cells prefixed with 1% paraformaldehyde. Statistical comparison of the observed maps with the expected random (Poisson) distribution revealed that surface Ig was highly non random. The same principle was used to map Ia antigens on lymphocytes. Cells from BIO.BR and C3H/HeJ mice (both having the I(k) haplotype) were labeled with an FITC conjugate of A.TH anti A.TL antibody (anti Ia(k)) followed by Fab anti FITC ferritin. Ia antigens were present in clusters with variable amounts of bare membrane. Labeling of enriched B cells (antitheta and complement treated) and T cells (nylon wool column purified) indicated that most B cells and only few cells in the T enriched population contained Ia specificities.
|Pages (from-to)||no. 4522|
|State||Published - Jan 1 1975|