[PubMed] [Google Scholar] 17. measured by a standard enzyme-linked immunosorbent assay. After the main vaccination, salivary MenA and MenC IgG and MenA IgA concentrations were significantly improved after immunization with both MACconj and MACPS vaccines, but the salivary Males C SCR7 IgA level was improved only after MACPS vaccine SCR7 ( 0.01). IgA reactions to both serogroups were higher for MACPS than MACconj vaccine ( 0.05), whereas no significant variations were seen for IgG responses. MenA IgG titers were higher after the MACPS booster in MACconj-primed subjects than Mouse monoclonal to Complement C3 beta chain after the MACPS main vaccination, suggesting the presence of IgG memory space. Antibody reactions to a dose of either MACPS or MACconj were not SCR7 significantly reduced in those previously given MACPS compared to the main responses to the people vaccines. Meningococcal A+C conjugate and PS SCR7 vaccines induce significant mucosal reactions in young adults. MACconj priming may induce IgG memory space in the mucosal level, which is likely to be a reflection of an anamnestic serum IgG response. No evidence of mucosal hyporesponsiveness was observed after MACPS priming with this study. Parenteral immunisation with meningococcus group C polysaccharide (PS) vaccine may induce local immunity in the nasopharynx against meningococci, since a significantly lower percentage of vaccinated armed service recruits became service providers of group C meningococci than did unvaccinated settings (6). The local immunity induced was specific for meningococcus group C. We as well as others have shown that upper respiratory tract mucosal antibodies are produced following meningococcus PS vaccination (20, 26), which could play an important role in avoiding immunized individuals becoming carriers. We also observed the levels of these antibodies declined rapidly to near-prevaccination levels after 6 to 12 months, raising the possibility that safety could be short-term (26). However, if vaccines induce immunological memory space in the mucosal level, long-term safety could be accomplished. The widespread use of such vaccines would not only guard immunized individuals against invasive disease but also potentially interrupt the chain of transmission, therefore protecting the unimmunized populace through herd immunity SCR7 or populace immunity. Meningococcal group A and C PS conjugate vaccines have recently been developed and shown to perfect for anamnestic serum immunoglobulin G (IgG) reactions to meningococcus serogroup C PS vaccine (13, 14, 16, 22). However, little information is definitely available about whether these vaccines induce immunological memory space in the mucosal level. There has been an increase in the proportion of group C strains in England and Wales, and older children and young adults have been at particular risk (8). Outbreaks of group C disease have occurred recently in English universities, prompting the common use of meningococcal PS vaccines for first-year college students in 1999. There have been recent reports suggesting that meningococcus group C PS vaccine may induce hyporesponsiveness or tolerance to subsequent doses of PS vaccine (7, 15, 23), raising the query whether use of meningococcus group C PS vaccine like a main immunization offers potential disadvantages. We have studied the primary and booster mucosal immune responses to an A+C meningococcal conjugate vaccine and an A+C meningococcal PS vaccine in young adults to assess whether these vaccines induce memory space mucosal reactions and whether main immunization having a PS vaccine induces hyporesponsiveness to subsequent PS or conjugate vaccine doses. MATERIALS AND METHODS Study subjects and vaccines. Healthy University or college of Sheffield college students aged 17 to 30 years were randomized to receive a single dose (0.5 ml) of either a group A+C meningococcus conjugate vaccine (MACconj [Aventis Pasteur]) (group 1, = 100) or a group A+C meningococcus PS vaccine (MACPS [Aventis Pasteur]) (group 2, = 95). One year.