ABSTRACT
Serum IgE is suppressed in CD23-transgenic (Tg) mice where B cells and some T cells express high levels of CD23, suggesting that CD23 on B and T cells may cause this suppression. However, when Tg B lymphocytes were compared with controls in B cell proliferation and IgE synthesis assays, the two were indistinguishable. Similarly, studies of lymphokine production suggested that T cell function in the Tg animals was normal. However, adoptive transfer studies indicated that suppression was seen when normal lymphocytes were used to reconstitute Tg mice, whereas reconstitution of controls with Tg lymphocytes resulted in normal IgE responses, suggesting that critical CD23-bearing cells are irradiation-resistant, nonlymphoid cells. Follicular dendritic cells (FDC) are irradiation resistant, express surface CD23, and deliver iccosomal Ag to B cells, prompting us to reason that Tg FDC may be a critical cell. High levels of transgene expression were observed in germinal centers rich in FDC and B cells, and IgE production was inhibited when Tg FDCs were cultured with normal B cells. In short, suppressed IgE production in CD23-Tg mice appears to be associated with a population of radioresistant nonlymphoid cells. FDCs that interface with B cells in the germinal center are a candidate for explaining this CD23-mediated IgE suppression.
Subject(s)
Dendritic Cells, Follicular/immunology , Dendritic Cells, Follicular/metabolism , Down-Regulation/genetics , Down-Regulation/immunology , Immunoglobulin E/biosynthesis , Mice, Transgenic/immunology , Receptors, IgE/biosynthesis , Receptors, IgE/genetics , Adoptive Transfer , Animals , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , Cells, Cultured , Cytokines/biosynthesis , Dendritic Cells, Follicular/radiation effects , Down-Regulation/radiation effects , Gene Expression Regulation/immunology , Immunoglobulin E/blood , Lymphocyte Activation/genetics , Lymphocyte Transfusion , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Radiation Tolerance/immunology , Receptors, IgE/immunology , Spleen/cytology , Spleen/radiation effects , Spleen/transplantation , Th1 Cells/immunology , Th1 Cells/metabolism , Th2 Cells/immunology , Th2 Cells/metabolism , Transgenes/immunologyABSTRACT
In the present study, modulation of antibody response induced by Hepatitis B virus vaccine-IgM complex was investigated. Purified IgM-type anti HBv monoclonal antibody (1B11) was complexed to commercially available HBv vaccine (GenHevac B Pasteur, France) at varying concentrations of HBsAg (0.5, 1, 1.5 microg of HBsAg) and used to immunize BALB/c mice. An enhanced humoral immune response was obtained with the HBv vaccine-IgM complex at all the doses compared with those immunized by vaccine alone and increased antibody levels were observed with increased concentrations of HBsAg in vaccine formulation. Immunization with HBv vaccine-IgM complex mostly generated IgG-type antibodies in the sera of mice, and also gave rise to the development of hybrid cells which predominantly produced IgG-type monoclonal antibodies. Hence, results from this study indicate that 1B11 can be effectively used to obtain a better immune response to HBv vaccine.
Subject(s)
Hepatitis B Antibodies/biosynthesis , Hepatitis B Vaccines/immunology , Immunoglobulin M/immunology , Adjuvants, Immunologic , Animals , Antibodies, Monoclonal/immunology , Cell Fusion/immunology , Hepatitis B Surface Antigens/immunology , Immunization, Secondary , Immunoglobulin G/biosynthesis , Immunoglobulin Isotypes/biosynthesis , Mice , Mice, Inbred BALB CABSTRACT
The immunogenic properties of 17beta-estradiol, immobilized in negatively charged polymer gels, were investigated, and the specificity of antibodies produced was analyzed. The polymer gels developed were composed of a hydrophobic estradiol core surrounded by hydrophilic polyanions as corona. As an immunogen, it was conceived to function via a dual mode, that is as a hapten-delivery system (prolongation effect) and as a polyelectrolyte adjuvant. Polymer gels containing estradiol appeared to possess a high estradiol-specific immunogenicity even without the addition of traditional adjuvants. A comparative study of estradiol trapped in polymer gels versus estradiol conjugated to bovine serum albumin (BSA.E) + Incomplete Freund's Adjuvant (IFA) mixtures revealed similar immunogenic properties in terms of induction of specific antibodies. Following a short immunization procedure based on the use of 17beta-estradiol immobilized in polymer gels, we developed 10 specific monoclonal antibodies with Kd values ranging between 1.2 X 10(-7) and 8 X 10(-8) M.
Subject(s)
Antibodies, Monoclonal/biosynthesis , Estradiol/immunology , Lipids , Adjuvants, Immunologic/pharmacology , Adjuvants, Immunologic/standards , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/isolation & purification , Antibody Affinity , Antibody Specificity , Freund's Adjuvant/chemistry , Freund's Adjuvant/immunology , Gels , Hybridomas , Methods , Mice , Serum Albumin, Bovine/chemistry , Serum Albumin, Bovine/immunology , Steroids/immunologyABSTRACT
Complex formation between synthetic polyelectrolytes (PE) [poly-4-vinyl-N-ethyl (cetyl), pyridine bromides-PVP(R2, R16)], bovine serum albumin (BSA), or 17 beta-estradiol-BSA conjugate (BSA.E) was studied in neutral water. Weakly water-soluble (colloidal) complex was formed upon addition of BSA.E to PVP (R2, R16) solution at pH 7. A nonrandom distribution of the protein molecules between the coils of polycations and self-assembly in the nonstochiometric polycomplex particles took place. The immunogenic properties of PVP (R2, R16)-BSA.E polycomplex were investigated and the specificities of produced antibodies analyzed. 17 beta-Estradiol introduced in polyelectrolyte complexes (PE-BSA) was found to invoke considerable increases in the steroid-specific immunoresponse. However, a comparative study of immunogenic activity of polycomplexes versus BSA.E+incomplete Freund's adjuvant (IFA) mixtures revealed some differences in regards to the specificity of antibody production. In contrast to IFA+BSA.E systems, polycomplexes were able to generate estradiol-as well as BSA-specific antibodies. Such a carrier-directed response may be determined by increase in immunogenicity of weak antigenic determinants and/or by the exposure of internally located determinants upon complex formation with polyelectrolytes. Fusions following the two different immunization procedures resulted in the growth of comparable numbers of estradiol-specific monoclonal antibodies with apparently similar antigen affinities. Thus, immunizations using antigens in PEC appear to provide an efficient alternative to IFA.
