A polysaccharide-protein complex from Haemophilus influenzae type b. 1. Activity in weanling rabbits and human T lymphocytes

A polysaccharide-protein complexprepared from Haemophilus influenzae type b strain Eagan was used as test antigen in an enzyme-linked immunosorbent assay for human serum antibodies. With washing buffer that did not contain detergent, the assay de-tected antibody to lipopolysaccharide (LPS) and to non-LPS somatic antigensas well as to polyribosylribitolphosphate (PRP). With buffer that did contain detergent, anti-bodies to LPS were not detected, whereas detection of antibodies to the non-LPS so-matic components and to PRP was unimpeded. Similarly, purified LPS could be used as test antigen with the former buffer only. IgG, IgA, and IgM antibodies to non-LPS somatic antigens were prevalent in healthy adults and children, and levels increased in 14 of 15 patients recovering from meningitis due to H. influenzae type b; IgG was the predominant class. Antibodies to LPS wereprevalent but at lowerconcentrations, and IgM was the predominant class; levels increased in 12 of the 15 patients. In weanling rabbits a polysaccharide-protein com-plex (PC) of Haemophilus influenzae type b elicited a vigorous antibody response to the cap