A Synthetic Disaccharide Analogue from Neisseria meningitidis A Capsular Polysaccharide
Stimulates Immune Cell Responses and Induces Immunoglobulin G (IgG)
Production in Mice When Protein-Conjugated
Some
new phosphonoester-linked oligomers, stabilized analogues of the corresponding
phosphate-bridged oligomers of Neisseria meningitidis A (MenA) capsular polysaccharide (CPS), were conjugated to human
serum albumin (HSA), as a protein carrier model, and studied for
immunological activities. We determined (i) in vitro, their biocompatibility
(CAM test) and activity in inducing both T cell proliferation (CFSE
method) and IL-2 release (ELISA), and (ii) in vivo, their ability
to stimulate specific IgG antibody production (ELISA). All HSA-conjugated
compounds induce T cell proliferation (40% of proliferation at 10<sup>2</sup> μM), whereas only the phosphonodisaccharide was effective
(28% of proliferation at 10<sup>2</sup> μM) among the unconjugated
forms. IL-2 release confirmed these results. In addition, the HSA-conjugated
showed in vivo the capacity of eliciting the production of specific
IgG antibodies. In conclusion, we obtained novel biocompatible, water-stable,
and immunoactive MenA CPS analogues. A short disaccharide fragment
showed the unusual behavior of triggering T cell proliferation in
vitro