Suppression turned idiotypic

Abstract

Suppressive effects of lymphocytes in immune responses had first been observed in the early 1970s (see chapter 7). The phenomenon of cellular immune suppression thus preceded the network theory and research on suppressor cells was carried out initially independent of network concepts, as a paradigm in its own right. In these initial experiments suppression was mostly associated with T cells from various lymphoid organs that, admixed to antigen-stimulated lymphocyte populations, diminished their reactivity as determined by T cell proliferation assays1–3. Thus, in these initial experiments both the suppressive and the antigen-reactive lymphocytes had been T cells, so that suppression was perceived as an affair among T cells only. However, the notable exception among these early observations was a report on allotype-specific suppression of immunoglobulin production by suppressor T cells, suggesting that B cells, even without antigen-stimulation, can be a target of T cell suppression as well4. The idea that in order to produce antibodies a B lymphocyte first has to escape from the suppressive effect of suppressor T cells fascinated Jerne, who speculated that: “T cells recognizing the idiotypes of B cell receptors may be assumed likewise to maintain B cell suppression. Conversely, we could conclude that, normally, B cells remain functional because of the absence of sufficient numbers of specific suppressor T cells...”5 Jerne’s speculation provided the incentive to merge the two paradigms, suppressor T cells and idiotypic network theory.