Haemophilus type B conjugate vaccine: postimmunization kinetics of IgM and IgG antibody responses in ten vaccinated children.

A new Haemophilus type b conjugate vaccine coupling capsular polysaccharide of Haemophilus influenzae b to tetanus toxoid is available in France and other countries. We have studied the kinetics of the immune response in ten children aged 17 to 50 months during the 4 weeks after immunization with one dose of Haemophilus type b conjugate vaccine. Eight serum samples were collected from each child at day 0 (D0), D2, D4, D7, D10, D14, D21 and D28. An ELISA method has been used to discriminate between IgM and IgG classes of anti-polyribosylribitol phosphate antibodies. A high level of IgM appeared at D7 and persisted until D28. The increase in IgG was regular and progressive from D7.

[Natural immunity to Haemophilus influenzae type b. ELISA study of the distribution of IgG, IgG1 and IgG2 in France and Africa]. / Immunité naturelle vis-à-vis d'Haemophilus influenzae b étude par méthode ELISA de la distribution des IgG, IgG1 et IgG2 en France et en Afrique.

A Haemophilus influenzae type b capsular polysaccharide-tetanus toxoid conjugate vaccine will be released for use in infants in developing and industrialized countries in the near future. This prompted a comparative study of the natural immunity of mothers and passive immunity of their newborns in France and Africa. An ELISA method capable of discriminating immunoglobulin classes and subclasses was used. Monoclonal antibodies were used to determine titers of IgG1 and IgG2 antibodies. Because capsular polyribose ribitol phosphate does not bind readily to polystyrene, the plate was coated with streptavidine which bound to biotin linked to the antigen. Antibody titers were found to be identical in French and African study groups. Both IgG1 and IgG2 antibodies were found, often with higher titers for the latter. Both subclasses were found in cord blood of French and African children.