The Changes in Serum Proteins and Blood Volume during Immunization

In rabbits hyperimmunized with pneumococcal vaccine high concentrations of gamma globulin are produced. In such rabbits, plasma volume was determined with (131)I-labelled rabbit albumin and red cell volume with (51)-Cr-labelled autologous red cells. It was found that the plasma volume increased with increasing gamma globulin concentration, the highest values observed being about 10 gm. per cent gamma globulin and about 70 ml. plasma per kg as against normal values of 0.6 to 0.7 gm. per cent gamma globulin and 30 ml. plasma per kg. The red cell volume was the same in immunized and in normal rabbits and consequently hemoglobin concentration fell with increasing gamma globulin.