The anamnestic antibody response to type 3 specific pneumococcal polysaccharide

The antibody response to secondary immunization with pneumococcal polysaccharides in mice

The benefit of re-immunization with pneumococcal polysaccharide vaccine is an important question in clinical practice. In an experimental model, BALB/c and CBA/J mice were re-immunized s.c. with a 23-valent pneumococcal polysaccharide vaccine at various time intervals after a first immunization with the same vaccine. The antibody response after the secondary immunization showed similar kinetics as after primary immunization, and was mainly an IgM antibody response. Re-immunization at 28 days or earlier induced a decrease in the serum antibody levels to the vaccine. Reimmunization at 120 days or later induced higher antibody levels than after the first immunization. Significant increases in antibody levels to serotypes 1, 4, 7F and 19F out of six serotypes tested were observed. In CBA/J mice, but not in BALB/c mice, the dose used for primary immunization appeared to influence the magnitude of the antibody response to secondary immunization. Our results indicate that the time interval between primary and secondary immunization is an important determinant with regard to the magnitude of the antibody response to re-immunization with pneumococcal polysaccharide vaccine.

Oligosaccharide-protein conjugate vaccines induce and prime for oligoclonal IgG antibody responses to the Haemophilus influenzae b capsular polysaccharide in human infants

The diversity of the IgG antibody induced by immunization of human infants and children with conjugate vaccines, composed of oligosaccharides prepared from the Haemophilus influenzae b capsular polysaccharide (CP) and covalently linked to diphtheria toxoids, was studied by analytical IEF. The antibody response was similar, in the degree of restriction, to that observed in the antibody response of older children to immunization with the CP alone. The booster responses induced by reimmunization with conjugate vaccines were accompanied by increases predominantly in the IgG antibody clonotypes expressed after the priming dose of vaccine. After a series of conjugate immunizations, immunization with isolated CP boosted the antibody titer and increased expression from all the clonotypes that were expressed after conjugate immunization. These findings suggest that the conjugate vaccines are acting on a limited number of human B cell clones that are preferentially restimulated after reimmunization. Little evidence of antigen-specific B cell recruitment was found. In addition, the ability of isolated CP immunization to restimulate the same B cell clone indicates that the responding B cell has matured and suggests a linear rather than a dual developmental pathway for the B cell participating in this human antibody response.

Elimination of allogeneic lymphocytes by mice

Two major classes of response to allogeneic lymphocytes can be detected in mice in vivo, based on injecting them intravenously with 51Cr-labelled lymph node cells and examining them in a short term assay. A natural immunity discriminating between allogeneic and syngeneic lymphocytes is seen in the lymph nodes (and to a lesser extent, the spleen), which has such close similarities to natural cell-mediated responses of the NK class as thymic-independence and radioresistance. However, it has immunological specificity of a conventional kind, probably towards serologically determined K/D antigens. There is also an active immune response, produced by immunisation with dissociated lymphoid cells or allografting, which consists of three elements: an IgG opsonising alloantibody response, diverting circulating lymphocytes to the liver; an IgM opsonin, localising them to the spleen; and a cell-mediated serum-dependent elimination mechanism that destroys cells entering the lymph nodes and spleen. Dose-response curves for the primary response show evidence of high-dose paralysis of elimination. Dose-time-response results for the secondary show a variety of unique characteristics; evidence is presented to suggest that several aspects of the phenomenon betray primitive features retained from an earlier stage in the evolution of the immunological system.

Humoral immune response in chinchillas to the capsular polysaccharides of Streptococcus pneumoniae

Vaccines made from the capsular polysaccharides of Streptococcus pneumoniae have been shown to reduce the incidence of pneumococcal disease in certain populations and have recently been evaluated for their ability to elicit protection against experimental pneumococcal otitis media in a chinchilla model. In this study, chinchillas were vaccinated with a dodecavalent preparation of pneumococcal capsular polysaccharides (PCP) to obtain more information on the immunogenicity of these polysaccharide antigens. All 12 PCP types elicited an antibody response, but the optimum PCP dose and the kinetics of the antibody response varied among types. Immunological paralysis was demonstrated with an immunogenic dose of PCP after primary immunization with a large PCP dose (25 micrograms or more). Pertussis vaccine acted as neither an immunoadjuvant nor an immunosuppressant in the serum antibody response to type 7F PCP in chinchillas.

Time and antigen dose-dependent variations of IgM antibody affinity

Affinity of IgM antibodies elicited in mice by a single injection of dinitrophenylated dextran was measured by equilibrium dialysis. Maturation of affinity was found to occur with time, the rate of increase being higher after larger antigen doses. Maturation was followed by a decrease of affinity with time, the fall being more pronounced after lower antigen doses. These findings are more in line with the theory of antigen-induced diversity rather than with the maturation theory.

Mechanisms by which hapten conjugates of pneumococcal polysaccharide interfere with the challenge of anti-hapten memory cells

Incubation of trinitrophenylated hemocyanin (TNP-KLH)-primed spleen cells with microgram amounts of 2,4-dinitrophenyl (DNP) or 2,4,6-trinitrophenyl (TNP) conjugates of pneumococcal polysaccharide type 3 (SIII) for as little as 5 min at 4 degrees C results in a specific "block" of the 19 S and 7 S adoptive memory response to TNP-KLH. This hapten-SIII-induced block of anti-hapten memory B cell responsiveness seems to be an example of specific receptor blockade. The block is specific and can be prevented by simultaneous incubation of the primed cells with hapten-protein conjugates which presumably compete with the hapten-polysaccharide for attachment to the B cell surface via anti-hapten Ig receptors. Removal via capping of these Ig receptors by exposure of TNP-KLH-primed memory cells to rabbit anti-mouse Fab serum for 45 min at 37 degrees C renders these cells refractory to the blocking effect of hapten-SIII. Once the hapten-SIII has attached to the memory cells, these blocked cells can be "rescued" (i.e. returned to a state of responsiveness) by incubating these cells with either mouse anti-SIII at 37 degrees C or rabbit anti-DNP serum at 4 degrees C. Since a papain digest of the IgG fraction of rabbit anti-DNP did not rescue the cells while the intact IgG did, a capping off of the TNP-SIII was proposed as the mechanims for this return to responsiveness of the hitherto blocked cells. A rescue was not seen by treatment of recipient mice with such B cell mitogens as dextran sulfate, endotoxin or purified protein derivative of tuberculin.

Cross-reactivity patterns of IgM and IgG anti-lipopolysaccharide antibodies in individual mice

A sensitive method has been developed which permits comparative analysis of IgM and IgG antibody specificity against lipopolysaccharide (LPS) antigen. It is based on hemolysis of LPS-coated red blood cells and on its inhibition by homologous and heterologous LPS. By appropriate use of anti-immunoglobulin sera, indirect (facilitated) lysis due to IgG antibodies is obtained, whereas IgM gives direct lysis and is 2-mercaptoethanol-sensitive. IgG can be analyzed either by facilitation with a rabbit anti-mouse Ig or with anti-allotype sera. By use of anti-allotype sera in F1 hybrids, both parental antibody types can be studied separately. Antibodies of either class from individual mice may display different cross-reactivity patterns. Furthermore, for IgM and IgG within a given serum, both similarities and differences have been found. Some of the cross-reactivity patterns have been followed over one year. With few exceptions, individual patterns remained constant throughout this period.

Selective roles of thymus-derived lymphocytes in the antibody response. II. Preferential suppression of high-affinity antibody-forming cells by carrier-primed suppressor T cells

Passive transfer of thymocytes and spleen cells from donors primed with keyhole limpet hemocyanin (KLH) caused significant decrease in the average avidity of anti-DNP antibodies produced by direct and indirect PFC in the recipients in both primary and adoptive secondary antibody responses against DNP-KLH. The analysis of the avidity distribution of antibodies produced by plaque-forming cells (PFC) indicated that the observed decrease in the average avidity is primarily due to the selective loss of high avidity subpopulation of PFC leaving low avidity subpopulation relatively unaffected. The degree of suppression in antibody avidity did not correlate with the reduction in the number of PFC, and thus causing the "shift" of avidity distribution of PFC to the low avidity end. These results indicate that the "maturation" of antibody in the T-cell-dependent antibody response is influenced by the carrier-specific suppressor T cells with respect to the emergence and selection of B cells having high affinity receptors for hapten. It is suggested that B cells binding antigen with high affinity receptors would be more easily affected than those with low affinity receptors by specific suppressor T cells which are capable of reacting the carrier portion of the same antigen.

Characterization of the antibody response to type 3 pneumococcal polysaccharide at the cellular level. II. Studies on the relative rate of antibody synthesis and release by antibody-producing cells

A procedure based on the rate of appearance of plaque-forming cells (PFC) in agarose was used to measure the relative rates of antibody synthesis and release by cells making antibody specific for Type III pneumococcal polysaccharide (SSS-III). The rate of antibody synthesis and release by SSS-III-specific PFC was directly related to the immunizing dose employed; maximal values were obtained with mice given an optimally immunogenic dose (0.5 μg) of SSS-III. However, dose-dependent reductions, not only in the magnitude of the antibody response, but also in the rate of antibody synthesis and release by specific PFC, were noted in mice receiving doses greater than 0.5 μg. The latter suggests that a decrease in the rate of antibody synthesis and release by antibody-forming cells may be an initial step in the induction of immunological paralysis by high doses of SSS-III.

Increases in the magnitude of the serum antibody and the PFC response were associated with corresponding increases in the rate of antibody synthesis and release by SSS-III-specific PFC following immunization; this suggests that cell differentiation—rather than proliferation—plays a major rôle in the development of the antibody response to SSS-III. In contrast, the results obtained in similar studies with sheep erythrocytes indicate that cell proliferation influences to a greater degree the magnitude of the antibody response elicited to this antigen.

Tuberculin-active carbohydrate that induces inhibition of macrophage migration but not lymphocyte transformation

A tuberculin carbohydrate fraction, GAE, in sensitized animals induced a delayed type of skin reactivity and inhibited the migration of macrophages but failed to stimulate lymphocyte transformation in vitro. Tuberculin protein-containing fractions were active in each test. These results show that in vitro lymphocyte transformation is not necessarily a corollary of delayed type hypersensitivity.