Low IgG response of the mouse strain C57BL/10ScSn after immunization with protein antigens.

The low IgG response of the strain C57BL/10ScSn is not restricted to the reaction to sheep red blood cells; but it can be demonstrated even after immunization with ARS, DNP or FITC haptens, coupled to various heterologous (BGG, RSA) or autologous (MGG) protein carriers. The level of the IgG response is - using the same immunization schedule - influenced both by the bound hapten and the carrier. In both strains tested (i.e. in the high-responding A/J and the low-responding C57BL/10ScSn), the highest IgG response is elicited by FITC-BGG. The response of the C57BL/10ScSn strain is, similarly as after immunization with SRBC, approximately ten times lower. The IgG response to other antigens tested was lower in both strains and therefore the quantitative differences were less pronounced. The affinity of antibodies against the ARS and TNP determinant, detected by inhibition of plaque-forming cells, is similar in the two strains. Thus the low reactivity of the strain C57BL/10ScSn is not caused by the absence of suitable VH and VL genes, but it rather indicates a defect of some general regulatory mechanism, involved in the synthesis of IgG antibodies. After repeated administration of ARS-BGG, the antigen and the antigen - antibody complexes accumulate in high concentrations primarily in the liver of mouse strain A/J. The amount of antigen accumulated in the liver of strain C57BL/10ScSn is significantly lower.