as alkylene containing from 1 to 10 carbon atoms wherein m and o are integers from 0 to 6 and n is an integer from 1 to 6 with alkylene being the especially preferred spacing group in these formulae m is 0 n is preferably an integer of from 1 6 most preferably 1 or 2 and o is preferably 0 or 1 in the compound of formula iv x u2032 is u2014 ch2 or a functional group linking the spacer to the carrier preferably to an amine group on a polymeric carrier the group x u2032 is the result of the terminal functional group x in the compound of formula iii which is capable of binding to a carrier preferably to an amino group in the polyamine polymer present in the carrier or used as the immunogen any terminal functional group capable of binding to a carrier preferably capable of reacting with an amine can be utilized as the functional group x in the compound of formula iii these terminal functional groups preferably included within x are wherein r 3 is hydrogen or taken together with its attached oxygen atom forms a reactive ester and r 4 is oxygen or sulfur.