REGULATION OF ANTIBODY-RESPONSE TO SRBC .2. EFFECT OF A NONSPECIFIC STIMULATION

  • 1 January 1981
    • journal article
    • research article
    • Vol. 27  (1) , 15-27
Abstract
The ratio of individual 7S isotypes after primary and secondary immunization with SRBC [sheep erythrocytes] was studied in the strain with normal IgG antibody formation (A/J)and in the strain which responds predominantly by formation of IgM antibodies and only by a low IgG antibody response (C57BL/10ScSn, hereafter referred to as B10). The greatest differences were found in the amount of PFC [plaque-forming cells] which produce the IgG2a isotype. In B10 mice the IgG2a/IgM ratio is more than 100 times lower than in A/J mice. The so-called natural antibodies to SRBC were detected in both strains and were only of the IgM class; they were slightly higher in B10 mice. Hemagglutination inhibition tests showed no greater differences between SRBC and erythrocytes of B10 mice than between SRBC and erythrocytes of A/J mice which might explain the lower IgG antibody levels after immunization with SRBC. T lymphocytes play an important role for the IgM-IgG switch. This activity of T lymphocytes can be partially substituted by certain substances like LPS [lipopolysaccharide] or even colony-forming activity. An attempt was made to influence the IgG level in B10 mice by administration of 10 .mu.g of LPS i.p. simultaneously with SRBC. In the high responder strain A/J, LPS administration led predominantly to an increase in IgG-producing PFC, while the amount of IgM increased only slightly. The effect of LPS on B10 mice was somewhat different. It increased the IgG level to such an extent that it was comparable to the level seen in A/J mice; it also increased the number of IgM-producing PFC so that the final ratio of IgG/IgM remained low in B10 mice.

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