Based on thorough studies of many groups using different techniques, the current view on iNKT-TCR/CD1d interaction is that the CDR2α, which discriminates type 1 and type 2

AV14 genes, is not at all, or only very weakly, involved in CD1d-restricted antigen recognition GS-1101 [30]. Whether this holds true for the rat still needs to be shown, especially since own preliminary data obtained with α-GalCer-CD1d dimers and iNKT-TCR transductants suggest that rat AV14 family members may indeed differ in their CD1d/antigen-binding properties. Our data on the F344 iNKT-TCR repertoire are fully consistent with the data from Matsuura and colleagues who used molecular biology methods (RT-PCR and analysis of cDNA libraries) to make predictions on frequencies and organ-specific distribution of rat iNKT cells, as well as on the proportion of canonical iNKT-TCR rearrangements within AV14-containing TCRs [9]. Nevertheless, we could not confirm the proposed organ specificity of AV14 gene usage. It was

not clear that Matsuura and colleagues analyzed several individual animals. Therefore, it is possible that their different results were due to variability between individual animals. Indeed, we found the proposed dominance of type 2 AV14 in spleen and a nearly equal distribution Maraviroc molecular weight of type 1 and type 2 in IHLs, but only in one of four F344 rats (Supporting Information Table 2, animal 2). The impossibility to detect iNKT cells in LEW rats is of particular interest since iNKT cells have been linked to autoimmunity in humans and mouse models and the LEW strain is widely used as model for organ-specific

autoimmune diseases such as experimentally PD184352 (CI-1040) induced encephalomyelitis, uveitis, and others. Importantly, the induction of these diseases is not successful in F344 rats [24-26]. Therefore, the clear differences in iNKT-cell frequencies between LEW and F344 rats (and probably between other inbred strains as well) offer the opportunity to map loci controlling the different frequencies and link them (or not) with known disease-associated loci, for example, controlling autoimmunity [24-26]. Moreover, the role of iNKT cells in the development of spontaneous type 1 autoimmune diabetes is not clear [1]. Thus, an obvious candidate for the analysis of iNKT cells are BB inbred rats as they are, apart from NOD mice, the only animal model available for this disease. The observed similarities in the frequencies and phenotype of F344 rat iNKT cells compared with those in the human already suggest that certain rat strains might result in valuable models to study iNKT cells in disease. Indeed, the rather simple mode of in vitro expansion is of special interest, since it opens the possibility of expanding and manipulating iNKT cells in vitro and testing the functional properties of the cells after adoptive transfer.