FIG. 5.

After identification of a potent antigen by screening the products of highly expressed genes, the contribution that mRNA levels make to antigenicity was examined, as this approach could be used to improve mechanisms of antigen prediction. Correlation of the responder frequencies for 82 antigens with their mRNA levels in both M. tuberculosis and M. bovis revealed a slight but significant relationship between expression level and antigenicity (Spearman's rank correlation coefficients, 0.35 [P < 0.005] and 0.3 [P < 0.005], respectively). In addition, linear regression analysis showed that 14% of a protein's antigenic potential is determined by the expression level of its gene. Using this information in tandem with other approaches should improve our ability to detect antigenic proteins.