Characterization and Mitogenic Activity of Haemophilus Influenzae Type B Capsular Polysaccharide

Abstract

Studies were conducted on the characterization of Haemophilus influenzae type b polysaccharide (HITB-PS) and its mitogenic activity upon peripheral lymphocytes. This capsular polysaccharide was found to contain hexosamines and hexoses in addition to the main components of ribose and ribitol phosphate. The molecular weight of HITB-PS was determined as 585,000. The affinity constant of HITB-PS to unfraction-ated lymphocytes was 3.13 × 10³ M⁻¹ with 1.11 × 10⁴ binding sites per cell.

HITB-PS was found to be mitogenic for both numan T and B lymphocytes. At optimum doses, a three to five fold increase in ³H-thymidine incorporation into T and B cells was observed. Higher than optimum doses resulted in suppression of this mitogenicity. The effect of concanavalin A (Con A) mitogenicity was detected in T and B cells treated with effective as well as suppressive doses of HITB-PS; the mitozenic activities of Con A and HITB-PS were found to be independent of each other.