The reason for loss of agglutinability of Pseudomonas aeruginosa cells heated to 60 degrees C.

The loss of agglutinability of live Pseudomonas aeruginosa cells by mild heating to 60 to 80 degrees C is due to denaturation of surface slime, which can no longer combine with antibodies but is still attached to the cell surface and thus prevents access of antibodies to the cell wall. Prolonged boiling or autoclaving would not only denature the slime but also detach it from cell surface and thus make the cells accessible to antibodies directed to cell wall antigens. Heated cells are, however, no longer agglutinable by antibodies directed to slime antigens. After prolonged boiling or autoclaving, a large amount of polysaccharides appeared in the supernatant, and concomitantly, total cell volume as measured by turbidity of the cell suspension was significantly reduced.