Characterization of antigen-binding receptors in vitro. I. An equilibrium method for measuring antigen binding in murine cells
Benfari, M.J.; Cooperband, S.R.; Moolten, F.L.
Journal of Immunology 119(4): 1427-1431
1977
ISSN/ISBN: 0022-1767 PMID: 894047 Document Number: 119799
A novel method is reported for studying the binding of soluble antigen (bovine serum albumin, BSA) to surface receptors on lymphoid cell populations under equilibrium conditions in the presence of 10% normal rabbit serum or 20 mg/ml of ovalbumin. Virtually no nonspecific uptake was demonstrated to nonlymphoid tissues. Detectable quantities of BSA could be found on nonimmune and immune lymphoid populations. The binding of BSA was antigen specific and was porportional to the number of binding cells. The quantity of antigen bound was proportional to the free antigen exposed to the population; saturation could be achieved with 1-2 .mu.g of antigen/1.2 ml of culture per 10 .times. 107 cells. The kinetics of antigen binding was very rapid and occurred within 10 min at 4, 27 and 37.degree. C. The binding was independent of the viability of cells. Binding was antigen specific and could be partially blocked by cross-reacting serum albumins, but not by non-cross-reacting albumins. Binding was independent of cytophylic antibody concentrations in the serum.