Influence of E. COLI POLysaccharide on the interaction of E. coli K+ and K- with polymorphonuclear leukocytes in vitro.

Both a K+ strain and a K- strain of E. coli withstand phagocytic killing by polymorphonuclear leukocytes and do not stimulate the respiratory burst, that accompanies phagocytosis in these cells, as compared with E. coli J 53 which are extensively and rapidly killed and stimulate the respiration of leukocytes. Both K+ and K- E. coli become readily phagocytosable after removal of their polysaccharide by heat treatment and are able to stimulate oxygen consumption by PMN. Heat treated E. coli J 53 stimulate the oxygen uptake of PMN less than live E. coli J 53. The polysaccharide extracted from either K+ or K- E. coli inhibits both phagocytosis of and the respiration stimulated by all the three heat-treated strains used. Instead the polysaccharide extracted from the phagocytosable strain J 53 stimulates the oxygen consumption of PMN exposed to the heat treated K- strain or heat treated J 53 itself.