VI Typhoid Flagellar and Heterophile Antibodies in Serums of Children

Abstract

The purpose of this investigation was to determine whether Vi, typhoid flagellar (H), and heterophile (sheep hemagglutinating) antibodies were present normally in children. Vi antibodies have been reported in the serums of normal adults. Typhoid H antibodies appear during immunization of adults against typhoid fever and then gradually disappear. Heterophile antibodies have been found in the serums of many normal adults. One hundred and twenty-six children's serums were obtained from blood specimens submitted to the Rhode Island Hospital laboratory for a variety of diagnostic purposes. The children were between one week and 15 years of age. None was diagnosed as having typhoid fever or related diseases. Twenty-five serums were secured from adults who had been immunized with typhoid-paratyphoid vaccine within recent years, and 25 from adults undergoing such immunization. Vi and typhoid H antibodies in the serums were titrated with test antigens consisting of human erythrocytes of group 0 sensitized with saline bacterial extracts containing the Vi and typhoid H antigenic substances, respectively. Heterophile antibody was titrated by agglutination of sheep erythrocytes. Vi antibodies were found in 70.6 per cent of the 126 children examined, and typhoid H antibodies in 62.9 per cent of 35 children. Eighty per cent of the 25 adults previously immunized with typhoid-paratyphoid vaccine possessed Vi antibodies, but only 40 per cent contained typhoid H agglutinates. Vi antibodies were present in all 25 adults undergoing immunization; typhoid H antibodies were found in 44 per cent. Heterophile antibodies were detected in 99.1 per cent of 110 children 8 and 98 per cent of the 50 adults. Vi and typhoid H antibodies appeared during late childhood, possibly as a result of an active immunization process by serologically related organisms. Although heterophile antibodies were widely distributed, both in children and adults, their titers were greater in very young children.