Polyclonal antibodies specific for serogroup X of N. meningitidis and uses thereof in diagnosis

A method of detecting Neisseria meningitidis serogroup X bacteria (NmX) in a biological fluid, the method comprising:

• (a) contacting a biological fluid from a subject having or suspected of having an infection by NmX with polyclonal antibodies specific to the capsular polysaccharides of the NmX and
• (b) determining the presence or the absence of the NmX in said fluid,
• wherein the polyclonal antibodies are obtained by immunization of a mammal with whole inactivated Neisseria meningitidis serogroup X bacteria followed by purification of the antibodies from serum of the immunized mammal by first affinity chromatography with protein G followed by second affinity purification with purified Neisseria meningitidis serogroup X capsular polysaccharides (cpsX), wherein said purified antibodies detect the NmX in the biological fluid sample in an immunoassay performed without culturing said biological fluid and wherein said antibodies do not cross-react with Neisseria meningitidis bacteria of serogroups A, B, C, Y and W.