SOLUBLE OLIGOVALENT ANTIGEN-ANTIBODY COMPLEXES .2. EFFECT OF VARIOUS SELECTIVE FORCES UPON RELATIVE STABILITY OF ISOLATED COMPLEXES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 37  (2) , 495-503
Abstract
Soluble oligovalent antigen-antibody complexes were isolated and analyzed by ultracentrifugation to assess the effect of several forces on the composition and stability of soluble complexes. Complexes were prepared with fluorescein (F) conjugates of rabbit serum albumin (RSA) or thyroglobulin (RTg) and high affinity rabbit anti-F antibodies. Isolated complexes containing 2 antigen molecules (Ag2 complexes) tended to dissociate and form an equilibrium with complexes containing 1 antigen molecule (Ag1 complexes). This equilibrium was thermolabile, concentration dependent and affected by the original combining ratio and the area in the gradient from which complexes were harvested. Small amounts of free antibody dissociated from soluble complexes form a dynamic equilibrium; this equilibrium was much less affected by the above parameters. Complexes apparently grow in size by a process analogous to polymerization of simple subunits, and the driving forces for polymerization are of a lower order of magnitude and are more affected by physical variables than the primary reaction between antibody and its antigen.