60 IMMUNO-CATALYSIS 



polysaccharide, agglutinated Type III pneumococci, and specifically 

 protected mice against Type III infection. These findings show that 

 these polysaccharides are, apparently, incapable of forming a polysac- 

 charide-protein antigenic complex in vivo with rabbit proteins, in a 

 manner, perhaps, comparable to those possibly formed when pure 

 polysaccharides are injected into mice and men. 



An interesting new observation on the effect of a large dose of 

 pneumococcal carbohydrate on antibody production is reported by 

 Felton, et al. (1947). A relatively large dose of antigenic polysaccharide 

 of pneumococci type-specifically "paralyzes" the immunological mech- 

 anism of mice during the life span or for 1 5 months. This paralysis was 

 reported to be due to the presence of polysaccharide. From observations 

 of a large number of "paralyzed" mice, the pneumococcus polysac- 

 charide was found present in the following tissues in order of decreas- 

 ing precipitinogen concentration: liver, spleen, kidney, skin, bone 

 marrow; irregularly present in muscle (especially Type III), lung, in- 

 testines, and urine, and absent in heart and blood. In three instances, 

 the polysaccharide was isolated, partially purified, and tested for im- 

 munizing activity. Type I, 5 gamma protected against 50,000 lethal 

 doses. Type II, 0.5 gamma against 500,000 lethal doses, and Type 

 III, 5 gamma against 500 lethal doses. The amount of polysaccharide 

 in the tissues gradually decreased with increasing interval following 

 injection; but after 1 5 months, it was still present in the liver of animals 

 paralyzed against Type I and II, and, in one experiment. Type III. 

 In addition, mice injected with a paralyzing dose of pneumococcus 

 whole-cell vaccine, showed a similar distribution of polysaccharide in 

 the tissues. These observations may indicate, as the investigators sug- 

 gested, that the large dose of polysaccharide "paralyzes" the antibody 

 forming mechanism of the animal, or that antibody formed is neutral- 

 ized by combining with polysaccharide and is immediately eliminated 

 because of the continuous presence of a large excess of antigenic 

 polysaccharide. 



The immunological paralysis is a typical specific blocking, for anti- 

 bodies to immunizing doses of heterologous antigens are synthesized. 

 The enzyme systems which synthesize other immune globulins must 

 therefore be in an intact state. Only the response to the polysaccharide 

 antigen is lacking. Since the polysaccharide antigen is found in nearly 

 all the cells of immunologically paralyzed animals, failure to demon- 



