PREPARATION OF HAEMOPHILUS INFLUENZAE TYPE B CAPSULAR POLYSACCHARIDE CONJUGATE VACCINE

Abstract

This work involves the preparation, characterization

and telting of a I

conjugate vaccine against diseases caused by Haemophilus injluenzae

' e b. This

vaccine will protect the group of people at high risk (infants and childr&n) against

the diseases caused by this organism. The vaccine was prepared by coubling of an I I Hib oligosaccharide with a carrier protein by reductive amination. Hib CPS was I purified and tested, then hydrolyzed. The hydrolyzed Hib CPS was fractionated , using Sephadex G-50 column. An oligosaccharide fraction was collected then

oxidized using sodium m-periodate . A tetanus toxoid fraction of moleJlar weight '

150 .kDa was prepared by fractionation of crude tetanus toxoid using! Sephacryl I S-300 column, and used as a carrier protein. Coupling of the oxidized Hib oligosaccharide to tetanus toxoid was carried out by addition Of sodium cyanoborohydride to a mixture of the two components. The resultanl conjugate

I was purified using Sephadex G-50 column then tested chemically and biologically. . l The ratio of carbohydrate to protein was found to be 0.1 : 1. Confirmation of chemical binding was carried out by ELISA using a standard burro serum raised against Hib CPS. The conjugate was tested in C57 BL/6J mice and wls found to I I I improve the response against Hib CPS. This response was found to be better than pre-inununization titer and also better than the titer obtained by injechon ofHib CPS alone in mice. The conjugate also showed a boosting effect in these mice. The inunune response elicited by the conjugate was compared with that elicitld by three I different licensed conjugate vaccines available in the market.