SPONTANEOUS BINDING OF VIBRIO-CHOLERAE TO HUMAN-LEUKOCYTES

Various lymphocyte subpopulations have the capacity to bind different strains of Gram-negative bacteria. The capacity of a strain of Vibrio cholerae, biotype EI Tor, isolated during an outbreak of cholera, to a dhere to mononuclear cells isolated from peripheral blood was evaluate d. V. cholerae binds to mononuclear cells in a dose-dependent manner. The binding was 76.1% at a cells/bacteria ratio of 1:200 and significa ntly decreased to 43.1% at a ratio of 1:1. The value of bound bacteria , a marker of the mean number of binding sites on the cell surface, de creased at lower cell/bacteria ratios. Studies on isolated cellular po pulations demonstrated that 51, 42 and 38%, respectively, of CD4+, CD8 + and B cells were bound by V. cholerae whereas monocytes exhibited a higher binding capacity. The data suggest that the percentage binding of V. cholerae to lymphocytes and monocytes was higher than the percen tage found in previous studies with Gram-negative bacteria such as Yer sinia enterocolitica, and Salmonella, but similar to Helicobacter pylo ri. The findings indicate that V. cholerae posseses multiple 'adhesins ' such as fimbriae, flagella, haemagglutinins, lipopolysaccharides, an d outer membrane proteins. The capacity to bind to blood lymphocytes m ay reflect the same capacity for the lymphocytes from the gastrointest inal associated lymphoid tissue. This cytoadherence may contribute to the uptake of V. cholerae from the gut and may contribute to activatio n of B cells and CD4+ lymphocytes.