Amount, avidity, and specificity of antibodies to Pseudomonas aeruginosa in normal human sera.

Seventy-two normal human sera from healthy blood donors were tested by an enzyme-linked immunosorbent assay in order to determine the amounts and avidities of immunoglobulins M and G antibodies to lipopolysaccharides of seven Fisher's immunotypes of Pseudomonas aeruginosa and to exotoxin A. The patterns of specificity for seven immunotypes in all individual sera were determined. These data show a predominance of antibodies directed to Fisher's immunotypes 7 and 4 in the human population tested and may reflect frequency of occurrence of immunotypes outside the hospital environment.