Production of monoclonal antibodies against Neisseria meningitidis using popliteal lymph nodes and in vivo/in vitro immunization: prevalence study of new monoclonal antibodies in greater São Paulo, Brazil

Analysis of cellular phenotype during in vitro immunization of murine splenocytes for generating antigen-specific immunoglobulin

Although various in vitro immunization methods to generate antigen-specific antibodies have been described, a highly effective method that can generate high-affinity immunoglobulins has not yet been reported. Herein, we analyzed a cellular phenotype during in vitro immunization of murine splenocytes for generating antigen-specific immunoglobulins. We identified a combination of T cell-dependent stimuli (IL-4, IL-5, anti-CD38 and anti-CD40 antibodies) plus lipopolysaccharides (LPS) that stimulates antigen-exposed splenocytes in vitro, followed by induction of the cells phenotypically equivalent to germinal center B cells. We also observed that LPS induced high expression levels of mRNA for activation-induced cytidine deaminase. We stimulated antigen-exposed splenocytes, followed by the accumulation of mutations in immunoglobulin genes. From the immunized splenocytes, hybridoma clones secreting antigen-specific immunoglobulins were obtained.

The design of new adjuvants for mucosal immunity to Neisseria meningitidis B in nasally primed neonatal mice for adult immune response

The aim of this study was to determine the value of detoxified Shiga toxins Stx1 and Stx2 (toxoids of Escherichia coli) as mucosal adjuvants in neonatal mice for immunogenicity against the outer membrane proteins (OMPs) of Neisseria meningitidis B. Mucosal immunization has been shown to be effective for the induction of antigen-specific immune responses in both the systemic and mucosal compartments. Systemic antibody levels (IgG, IgG1, IgG2a, IgG2b, IgM, and IgA) and mucosal IgM and IgA were measured by ELISA using an N. meningitidis as an antigen. In addition, IFN-γ and IL-6 production were measured after stimulated proliferation of immune cells. Intranasal administration elicited a higher anti-OMP IgA response in both saliva and vaginal fluids. Our results suggest that both Stx1 and Stx2 toxoids are effective mucosal adjuvants for the induction of Ag-specific IgG, IgM, and IgA antibodies. The toxoids significantly enhanced the IgG and IgM response against OMPs with a potency equivalent to CT, with the response being characterized by both IgG1 and IgG2a isotypes, and increased IFN-gamma production. Additionally, bactericidal activity was induced with IgG and IgM antibodies of high avidity. These results support the use of the new toxoids as potent inducing adjuvants that are particularly suitable for mucosal immunization.

Storage and stability of IgG and IgM monoclonal antibodies dried on filter paper and utility in Neisseria meningitidis serotyping by Dot-blot ELISA

Background

A simple filter paper method was developed for, the transport and storage of monoclonal antibodies (Mabs) at room temperature or -20°C after spotting on filter paper, for subsequent serotyping of outer membrane antigens of N.meningitidis by dot-blot ELISA.

Methods

Monoclonal antibodies (Mabs) were spotted within a 0.5–1 cm diameter area of Whatman grade 903 paper, which were stored individually at room temperature or at -20°C. These MAbs were stored and analyzed after periods of one week, 4 weeks, 12 months, or 13 years in the case of frozen Mab aliquots, or after 4 weeks at -20°C or at room temperature (RT) in the case of Mabs dried on filter paper strips. Assays were performed in parallel using dot-blot ELISA. In addition to the MAbs specific for serotyping class 1, 2 or 3, we used a larger number of Mabs for polysaccharides, lipooligosaccharides (LOS), class 5 and cross-reactive antigens for native outer membrane of N.meningitidis. The Mabs dried on filter paper were eluted with phosphate-buffered saline (PBS) containing 0.2% gelatin.

Results

Mabs of the isotypes IgG and IgM dried on filter papers were not affected by duration of storage. The detection by serotyping Mabs was generally consistent for dried filter paper MAb samples stored frozen for over 1 year at -20°C, and although decreased reactive antibody titers were found after storage, this did not interfere with the specificity of the Mabs used after 13 years as dry spots on filter paper.

Conclusion

The use of filter paper is an inexpensive and convenient method for collecting, storing, and transporting Mab samples for serotyping studies. In addition, the samples occupy little space and can be readily transported without freezing. The efficiency of using immunoglobulin G (IgG) or M (IgM) eluted was found to be consistent with measurement of IgG or IgM titers in most corresponding, ascites Mabs stored frozen for over 1 year. The application of meningococcal typing methods and designations depend on the question being asked.