Effect of transplantable plasma-cell tumors on antibody response in mice.

The response to primary antigenic stimulation was measured in CH mice bearing two types of plasma-cell tumours, the 5563 tumour producing γ-type myeloma proteins and the 5674 tumour producing β-type myeloma proteins. Haemocyanin and pneumococcus type III polysaccharide, which produce 6.5S antibodies, and sheep erythrocytes, which produce 18S haemolysins, were used. Levels of serum antibody to all antigens were low in mice with the plasma-cell tumours, compared with those in normal mice, or mice with a mammary carcinoma. The larger the tumour, the lower were the antibody levels. Antibody levels were lower generally with the 5563 tumours than with the 5647 plasma-cell tumours of similar weight. Although rapid catabolism of normal gamma globulins contributes to the low level of serum antibody in mice with the 5563 γ-type tumour, diminished responsiveness of the antigen-susceptible cells appears to be the principal factor in the impaired antibody response in mice with the 5647 β-type plasma-cell tumour.