Figure 2.

Reverse transcription–PCR expression assays of putative immunity genes in naïve and bacterially challenged cell lines. Expression levels of the 38 A. gambiae putative immunity genes (Tables 2–4) were assayed by reverse transcription–PCR on RNA extracted from a naïve cell line (N) and a cell line that had been incubated with heat-killed E. coli and Micrococcus luteus for 8 h (I) as described (15). The cell line cDNA templates were normalized for the expression of the ribosomal protein S7 gene (S7), and the numbers of PCR cycles were empirically estimated for each transcript to avoid overamplification; specific primers were used for optimal amplification of products ranging in length from 250 to 500 bp at an annealing temperature of 58°C. Of the 38 putative immunity genes, one previously known was shown to be inducible but is not shown (II.3); 18 others, as shown, are transcriptionally activated in the cell lines 4A-3A (A) and 4A-3B (B). One putative receptor (II.8) is repressed by immune challenge.