To generate allorecognition outcomes from the simulated values of allotypic similarity, threshold proportions of overall allotypic similarity necessary to produce fusion, transitory fusion, and rejection must be superimposed on the simulated values.
Such intransitivities suggest that siblings need not share all allotypic determinants in order to be fusible (reviewed in Grosberg 1988).
However, to the extent that fusion requires a higher degree of allotypic matching than does rejection, the proportion of unique compatibility groups in a compatibility matrix need not be positively related to the level of allotypic disparity among the genotypes used to construct the matrix.
An analysis of patterns of allotypic similarity could, in principle, provide some insight into the formal genetics of allorecognition.
Thus, the mean similarity index (as calculated above) based on shared patterns of allotypic response between all pairs of full sibs is 0.
The simulations assessed how variation in three key genetic parameters affects patterns of allotypic similarity and compatibility frequencies among (1) full sibships; (2) half sibships; and (3) randomly drawn pairs using a simple additive model.
Next, we used this information to identify threshold proportions of allotypic similarity (i.
Consequently, the overall [TABULAR DATA FOR TABLE 4 OMITTED] allotypic similarity among siblings across loci will also decrease, as reflected in the downward "migration" of a given coded section as n increases.
High levels of allotypic specificity could, however, result from any number of genetic alternatives, ranging from one or a few loci with tens to hundreds of alleles per locus (characteristic of populations of botryllid ascidians: Milkman 1967; Mukai and Watanabe 1975a,b; Scofield et al.
As confirmed by similar observations of Vaidya and Beatty (16), polyclonal murine IgG prepared from many animals seems to be the best reagent to block interferences by such HAMAs because it will present all allotypic and cross-reactive idiotypic epitopes expressed on murine IgG molecules, whereas blocking reagents based on a single monoclonal antibody, such as MAK33, can be unsuitable when they are missing the respective epitopes.
In summary, our data demonstrate that, in patients treated repeatedly with the same monoclonal antibody, a considerable percentage of the HAMA response is directed against allotypic and cross-reactive idiotypic determinants.