The dosage requirements for immunological paralysis by soluble proteins.

The quantitative dose requirements for induction of paralysis by BSA in mice has been the subject of further study. Parallel studies have been made with lysozyme, ovalbumin, diphtheria toxoid and ribonuclease, in which similar paralysing and immunizing procedures were used, and similar direct binding tests applied to measurement of the response. In normal adults all the antigens tested induced high-zone paralysis and concomitant immunization, but BSA alone induced low-zone paralysis. With irradiation, with courses of injection commencing at birth, and with paralysis-maintaining treatment, all the antigens tested induced paralysis in a zone quantitatively similar to the low zone detectable in normal adults with BSA. Neither irradiation, treatment with cortisol, nor thymectomy affected the rate of induction of paralysis in the low zone. On the other hand the minimum dose required for immunization varied markedly from one antigen to another. The ability of BSA to induce low-zone paralysis in normal adults can, therefore, be attributed to the failure of low doses of this antigen to immunize. The consistency of paralysis threshold, in contrast to the variability for immunization, is interpreted as evidence of an additional step of complexity involved in immunization that is not required for paralysis.