Figure 3. Determinations of the relative amounts of Ogawa antigen in LPS preparations of the generated Hikojima strains MS1568 and MS1580 based on amounts of methylated and un–methylated perosamine analyzed with mass spectrometry in relation to similar analyses of LPS preparations from reference Inaba Phil6973 and Ogawa Cairo 50 strains.

The area under the curve for the methylated part (m/z ratio 756.6) divided by the area under the curve for the non–methylated part (m/z ratio 742.6) subtracted with the background (this ratio from the Inaba strain Phil6973) was used for the two Hikojima strain (MS1568 and MS1580) LPS preparations to calculate their percentage of Ogawa LPS (compared to the 100% Ogawa in the LPS from the Cairo50 reference strain). Diagrams are from one of 3 such experiments showing closely similar patterns and with the calculated mean ± SEM percentages Ogawa antigen indicated for MS1568 and MS1580.