Biomedical subjects

I Lorbach

Publications and source records attributed to I Lorbach.

3 recordsLinked to original sources

PubMed1981

Regulation by complementary idiotypes. Ig protects the clone producing it.

A/He mice actively producing complementary or anti-idiotypic antibody directed against a combining site structure for phosphorylcholine (PC) have profound and long-lasting suppression of their response to PC. B cells from unresponsive mice are unresponsive in vitro, and attempts to demonstrate suppressor cells in unresponsive mice were unsuccessful. Although the process ultimately responsible for suppression has not been defined, suppression can be initiated by anti-idiotypic antibody alone and prevented by complementary Ig; i.e., by anti-PC antibody. Furthermore, a suppressed anti-PC response can be rescued by sublethal irradiation and anti-PC antibody given passively. The recovery of the suppressed response is slow and presumably results from maturation from "stem" cells, which are protected from tolerization by the passively given antibody. Thus, by extrapolation, one of the functions of secreted Ig may be to protect the clone that produces it.

Animals↗

PubMed1978

Simultaneous complementary idiotypic responses: absence of reciprocal regulation.

Complementary antibodies, i.e. antibodies having combining site structures which are at least partially directed against each other, were induced in A/He mice by immunization with phosphorylcholine (Pc) coupled to keyhole limpet hemocyanin or with the Pc-binding IgA myeloma protein, HOPC-8 (H8). Both responses were monitored by enumerating plaque-forming cells and assaying serum antibody levels to Pc and H8. Prior immunization with H8 markedly suppressed subsequent immunization with Pc and vice versa; neither plaque-forming cell response was diminished, however, when mice were immunized simultaneously with Pc and H8. Experiments were designed to determine if the absence of reciprocal regulation was due to change in idiotypes. This was determined by measuring inhibition of plaque formation using complementary antibody. Plaque formation by cells was equally inhibited by high dilutions of the appropriate complementary antibody whether cells were from mice immunized with one, the other, or both antigens. Thus, the absence of regulation could not be accounted for by emergence of different idiotypes. Interestingly, sera from mice immunized to have high responses to both antigens were relatively ineffective in inhibiting plaque formation or suppressing immunization to Pc. However, such sera contained complexes of the complementary antibodies; apparently antibody to Pc in such sera quenches or neutralizes the activity of anti-H8 antibody. But the formation of complexes, at least measurable levels of circulating complexes, must be a result rather than the cause for the absence of reciprocal regulation, since regulation was also absent when immunization to Pc was manipulated so that responses were too low to result in detectable levels of circulating antibody to Pc. It is proposed that simultaneous complementary responses may occur in nature to other antigens and antibodies, and that such simultaneous responses may cause pathologic changes.

Animals↗

PubMed1976

Suppression by autogenous complementary idiotypes: the priority of the first response.

Complementary idiotypes or antibodies are considered to have combining site structures which are at least partly directed against each other. Complementary antibodies were induced in A/He mice by immunization with phosphorylcholine (PC)-containing antigens and by immunization with the PC-binding IgA myeloma protein TEPC-15 (T15). Both responses were monitored by enumerating plaque-forming cells (PFC) and assaying serum antibody levels against the corresponding antigens. Mice immunized at least three times with T15 in adjuvants had markedly suppressed responses to subsequent immunization with PC; similarly, mice preimmunized multiple times with PC had suppressed responses to immunizations with T15. In contrast, mice immunized with T15 in the interval between "primary" and "secondary" immunizations with PC had undiminished PFC responses to both antigens but significantly decreased antibody titers to PC. Simultaneous responses were also induced by immunizations with T15 superimposed on weekly immunizations with PC; with this regime, immunization with T15 actually enhanced the PFC response to PC, but serum antibody to PC was significantly lower than for mice immunized with PC only. Levels of serum antibody to PC were probably lower, either because anti-PC antibody was complexed with the complementary antibody directed against T15, or because the antibody directed against T15 prevented synthesis and/or release of anti-PC antibody by cells in vivo. Thus, an established prior autogenous immune response can dramatically suppress a subsequent primary complementary response, but the effects of complementary responses on each other are more complex with different sequences of immunization. Also, the effects of variables such as the amounts and ratios of the classes of antibodies on regulation of complementary responses remain to be defined.

Animals↗