Antibody‐induced redistribution of HL‐A antigens at the cell surface

Abstract

The in vitro binding of anti-HL-A antibodies t o the membrane of human lymphocytes induces important changes in the distribution of HL-A antigens on the cell surface. Following either direct or indirect immunofluorescence staining at 0 OC, cell-bound anti-HL-A antibodies are dispersed all over the cell surface. When the washed, stained lymphocytes are warmed and incubated at 37 "C, fluorescent antibodies cluster progressively a t the cell surface. They form large spots of fluorescence, and sometimes single caps at one pole of the cell, outside which HL-A antigens are no longer detectable, but other antigens can still b e found. Similar findings were made in electron microscopy, following indirect labeling of HL-A antigens on human lymphocytes, with ferritin or plant virus as the markers.With the indirect immunofluorescence technique, anti-human thymocyte antibodies and anti-mouse H-2 antibodies were found t o induce a similar redistribution of the corresponding antigens.The mechanism and the interpretation of this displacement of surface antigens by antibodies are still unclear and are discussed in terms of membrane structure and immunological significance.

Biochemical analysis of ligand-induced receptor patching and capping using a novel immunolactoperoxidase iodination technique.

“…1 a. However, if the immunolabeled cells are incubated at 37°C for 30 min, the H-2 antigens are induced to form aggregates on the cell surface which are typical of patching and capping as previously reported (8,18,25) (Fig. 16 ) .…”

“…The proportion of patched and capped cells is enhanced to a maximum of 50-60% of the total population if the cells are treated with both primary and secondary antibodies (8,18,25) . Consequently, a double-antibody treatment (i.e., mouse anti-H-2 b antibody and goat anti-mouse antibody), designated anti-anti-H-2 antibody, was used throughout all the experiments.…”

Anionic Sites of Human Erythrocyte Membranes

“…Allowing the ghosts to reseal before addition of antispectrin prevents entry of ferritin antispectrin and prevents antispectrin-induced surface aggregation . The time and temperature dependency of the change in CIH site topography is also consistent with known aggregation times of membrane components (Edidin and Weiss, 1972 ;Karnovsky et al ., 1972 ;Kourilsky et al ., 1972 ;Taylor et al ., 1971) . Finally, the requirement for specific -y-globulin antibodies (antispectrin Fab or antidinitrophenyl -y-globulins had no effect) demonstrates that antibody binding itself is not sufficient for the aggregation effect .…”

“…Fortunately, there is now ample evidence for a fluid structure of biological membranes (Fluid Mosaic Membrane Model [Singer and Nicolson, 1972]) where lateral diffusion of membrane components is expected . Several investigators have shown that y-globulin antibodies cause aggregation of external surface receptors (Edidin and Weiss, 1972 ;Karnovsky et al ., 1972 ;Kourilsky et al, 1972 ;Taylor et al ., 1971 ;Unanue et al ., 1972) .…”

Reversibility of cell surface label rearrangement.

“…The disappearance of labeled sites from areas of ruffling activity is a major feature of the rearrangements seen. Both this ruffling activity and the rearrangement of label are sensitive to cytochalasin B, and ruffling activity, perhaps along with other cytochalasin-sensitire structure, may play a role in the rearrangements of labeled sites.Evidence from a number of laboratories indicates that the application of label to cell surfaces causes a rearrangement of randomly distributed membrane molecules (12,15,20,30,35,43,51,53). Rearrangement is not a general membrane phenomenon, but involves only the labeled sites; surface molecules which do not interact with the label remain in a random, homogeneous distribution (29).…”