RELATIONSHIP BETWEEN COLONIAL MORPHOLOGY AND ADHERENCE OF STREPTOCOCCUS-PNEUMONIAE

Phase variants in colonial opacity of pneumococci differ in the abilit y to colonize the nasopharynx of infant rats. To explain this observat ion at a cellular level,,ve compared the ability of opacity variants t o adhere to buccal epithelial cells, type II pneumocytes, or vascular endothelial cells and to the glycoconjugates that represent the cognat e receptors at each of these sites. The transparent phenotype was asso ciated with enhanced adherence to buccal cells (similar to 100%) and t heir receptor relative to that of the opaque variants. Only modest dif ferences in adherence (<45%) were demonstrated to resting lung and vas cular cells. In contrast, adherence of transparent variants increased by 90% to lung cells stimulated with interleukin-l and by 130% to endo thelial cells stimulated with tumor necrosis factor. In contrast, cyto kine stimulation did not influence the adherence of opaque pneumococci . This difference correlated with the unique ability of transparent va riants to adhere to immobilized GlcNAc and to cells bearing transfecte d platelet-activating factor receptors. These results suggest that the mechanism of enhanced colonization of the nasopharynx in vivo by tran sparent as compared with opaque phase variants involves a greater abil ity to adhere to both GlcNAc beta 1-3Gal on buccal epithelial cells an d GlcNAc and PAF receptors on cytokine-activated, as opposed to restin g, lung and endovascular cells.