There are three questions under re-examination here that have been inspired by Bretscher's 'Two-step, Two-signal' model. First, what is the nature of the steps required in order for antigen-responsive cells to become effectors? Second, how does the immune system get started? Third and the most troublesome, what is the mechanism that relates the delivery of… (More)
The existence of antigen-receptors, BCR, and T cell antigen-receptors, that are “polyreactive”, necessitates a rethinking of its effect on two problems faced by the “adaptive” immune system: the self (S)–nonself (NS) discrimination and the determination of effector class. Here, we will concentrate on the impact of polyreactivity on the S–NS discrimination.… (More)
Colin Anderson correctly challenges the assumptions that I feel are crucial to understanding immune responsiveness. In order to address his concerns, I will follow the format of his analysis.
In analysing the Zinkernagel and Hengartner's 'Credo 2004,' Anderson introduces his 'development-context model' for the immunity-tolerance discrimination. He compares this model with the 'geographical model of Credo 2004' and our 'time-based two-signal model'. The discussion here deals with the advantages and limitations of the Anderson model considered… (More)
If it were possible to clone in vitro cells of any type, at any stage of differentiation, from an extensively characterized animal such as the mouse, many areas of cell biology would benefit. Indeed, it would be even more helpful if these cells could subsequently be restored to their normal in vivo phenotype whenever required. Here, we describe a step on… (More)
A single injection of dextran B1355 into BALB/c mice results in a rapid Xt anti-a(1,3) dextran response (1-3). One of the genes controlfing this response is in the heavy chain locus (1, 4) and is symbolized as v~,~t 31 (3). Mice lacking this gene fall into two classes: those that yield a ~-anti-a(l,3) response after repeated injections and those that never… (More)