Figure 3

Comparison of the hypervariable regions of MMTV SAg cDNA isoforms and their putative TCR Vβ specificity. A. Phylogenetic tree of the C-terminus hypervariable regions of 56 SAg cDNA isoforms isolated from 18 different tissues. The C-terminus hypervariable regions (~74 amino acids) of the 56 SAg cDNA isoforms were phylogenetically analyzed. The C-terminus sequences that were found in more than one tissue type are indicated using various shapes and shades: black diamond (identical to Mtv-8); gray triangle (identical to Mtv-9); black circle (identical to Mtv-17); black box (identical to Mtv-30); gray box and black triangle (sequences [non-reference] shared among different tissues). * indicates a representative C-terminus sequence shared among different tissues. B. Phylogenic relatedness of 17 unique C-terminus sequences selected from the 56 SAg isoforms, which were isolated from 18 different tissues. Four reference C-terminus sequences from Mtv-8, Mtv-9, Mtv-17, and Mtv-30 are highlighted with gray. black diamond (identical to Mtv-8); gray triangle (identical to Mtv-9); black circle (identical to Mtv-17); black box (identical to Mtv-30). C. Comparison of the C-terminus hypervariable regions of 17 SAg isoforms. The unique C-terminus sequences of 17 SAg isoforms were compared with ones from four reference SAg sequences of Mtv-8, Mtv-9, Mtv-17, and Mtv-30. The SAg isoforms, identical to the individual reference SAgs, are indicated using various gray shades. D. Putative TCR Vβ specificity of SAg isoforms. Divergence of the SAg isoforms in regard to their putative TCR Vβ specificity was estimated by comparison with the TCR Vβ specificity of four reference SAg sequences from Mtv-8, Mtv-9, Mtv-17, and Mtv-30.