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At least 19 recordsLinked to original sources
PubMed1977

Suppression of anti-hapten antibody response in vitro by hapten-carrier conjugates.

Production of antibodies was stimulated or suppressed arbitrarily by antigen treatment in vitro of spleens cultured at various time intervals after in vivo immunization. Spleens of mice immunized to the 2,4-dinitrophenyl or (4-hydroxy-3-iodo-5-nitrophenyl)acetyl haptenic determinants produced antibodies in culture when no antigen was applied in vitro. When a conjugate of the hapten to the same carrier employed for priming was given in vitro, an initial reduction of the response was observed, the level of which was dependent on antigen dose. Subsequently, increased amounts of antibodies were measured. In contrast, in vitro exposure to the hapten conjugated to an unrelated carrier resulted in significant reduction of the response for the entire period of the test. This suppressive effect manifested with various carrier proteins (ovalbumin, bovin IgG, bovine and rabbit serum albumin and keyhole limpet hemocyanin), when when applied to cultures in doses which were potentially immunogenic.

Animals↗
PubMed1979

Fine specificity of cytotoxic T lymphocytes: C57BL effector cells induced by autologous cells modified with hapten (4-hydroxy-3-nitro-phenyl)acetyl (NIP) are not heteroclitic.

Cytotoxic T lymphocytes (CTL) were generated to syngeneic cells derivatized with serologically cross-reactive compounds (4-hydroxy-3-nitro-phenyl)acetyl (NP) and (4-hydroxy-5-iodo-3-nitro-phenyl)acetyl (NIP) in order to investigate the possible role of a heteroclytic T and B cell receptor marker (U. Krawinkel et al., Eur. J. Immunol. 1977. 7:566) in CTL-target cell interaction. The cytotoxic cells of both BALB/c and C57BL/10 (B 10) origin react specifically with target cells of the inducer type; no heteroclicity of the overall cytotoxic response can be observed by CTL of B 10 origin. The results suggest that in this system, the specificity of CTL is determined by a receptor with a variable region different from that of the isolated NP-specific antigen-binding T cell receptor material.

Animals↗
PubMed1975

Disturbance of hapten-antibody equilibria by ammonium sulphate solutions. A source of error in antibody affinity determinations.

The affinity of anti-hapten antibody can be conveniently measured by precipitating immune complexes with ammonium sulphate. The method has, however, not proved very reproducible. Here is described one variable difficult to control in the assay: the ammonium sulphate was found to cause dissociation of ligands from hapten (NIP)--antibody complexes. The reason was the volume increase caused by addition of ammonium sulphate. The study suggested that in the calculation of the free hapten concentration the final volume during precipitation should be used. The precipitate should not be washed when hapten binding capacities are measured.

Ammonium Sulfate↗
PubMed1978

Immune reactivity during aging. I. T-helper dependent and independent antibody responses to different antigens, in vivo and in vitro.

The immunological status during aging was assessed by measuring the antibody response of the long-lived (C3H/eb X C57Bl/6J)F1 mice to various antigens in vivo and in vitro. In vivo, a decrease in antibody production to DNP and NIP haptenic determinants coupled on to BGG, as well as the response to SRBC, was observed. The decline was more pronounced in the IgG as compared to IgM antibodies. The results were recorded when various parameters such as antigen dose and kinetics of the response, were considered. Reduction of the antibody response was also noted when PVP was employed as immunogen. Similar results were noted when the responses to SRBC and DNP--polylysine were induced and followed in spleen organ cultures. In all of these experimental systems, the peak response was observed in mice 6--12 months old. From then on a gradual decrease was manifested, mice 30--36 months old producing significantly low responses. The results demonstrate that decrease in antibody production is expressed in the isolated spleen tissue in the same manner as in the intact animal. Furthermore, they were interpreted as indicating that the lesion may be at the T helper and the B cell compartments.

Aging↗
PubMed1992

Metal-binding chimeric antibodies expressed in Escherichia coli.

Metallothionein, a well-characterized biological chelator of metals, has been genetically fused to the binding domain of an antibody and expressed in the periplasm of Escherichia coli. Specific delivery of 109Cd to immobilized hapten or to haptenated cells was demonstrated directly in periplasmic extracts. This approach is potentially useful for targeted radiotherapy and diagnostic imaging. We find six to seven atoms of metal per active antigen-combining site. Absence of the Fc portion of the immunoglobulin along with low immunogenicity of metallothionein-metal complexes should reduce immunologic reactions.

Amino Acid Sequence↗
PubMed1976

Cell-mediated lympholysis of N-(3-nitro-4-hydroxy-5-iodophenylacetyl)-beta-anaylglycylglycyl-modified autologous lymphocytes. Effector cell specificity to modified cell surface components controlled by the H-2K and H-2D serological regions of the murine major histocompatibility complex.

Splenic lymphocytes from four C57BL/10 congenic mouse strains were sensitized in vitro to N(-3-nitro-4-hydroxy-5-iodophenylacetyl)-beta-alanylglycylglycyl-(N) modified autologous lymphocytes. The effector cells generated after 5 days of culture were assayed on a series of either N-modified phytohemagglutinin-stimulated spleen cells or N-modified tumor cells. The results indicated in all cases that both N modification of the targets and H-2 homology between the modified stimulating and target cells are required for lysis to occur. In each case the effector cells were found to lyse N-modified target cells only when there was homology at either or both ends of the major histocompatibility complex (MHC) between the stimulator and target cells. B10.BR lysed targets sharing alleles at K (or K plus I-A) and/or at D. B10.A effector cell specificity was mapped to K (or K plus I-A) and/or the D half of the MHC (D or D plus I-C and/or S). The two regions of specificity determined for B10.D2 effector cells were D (or D plus S plus I-C) and a region not including D of the MHC. C57BL/10 effector cells lysed N-modified targets only if there was target cell H-2 homology at K, I-A, and I-B or at the D serological region. As in the trinitrophenyl (TNP) system (6) B10.BR and B10.A effector cells lysed targets sharing K end H-2 serological regions greater than target cells sharing D-end serological regions. The C57BL/10 effector cells were shown to react to the K end greater than the D end, which differed from the equal reactivity seen in the TNP system for this strain. The data are consistent with the hypothesis that the antigen recognized by the effector cell includes an altered H-2 serological cell surface product. That the reaction is not "hapten specific" and the H-2 homology is required only for effector:target cell interaction was excluded by the use of two F1 combinations in which lysis of only N-modified target cells sharing the H-2 haplotype with the stimulating parental strain was obtained. Finally, it was demonstrated that N and TNP modification create distinct new antigenic determinants, since an effector cell sensitized to one modifying agent will lyse only H-2 matched target modified with that same modifying agent.

Animals↗
PubMed1976

Antigen-induced aggregation and modulation of receptors on hapten-specific B lymphocytes.

Mouse spleen cells were subjected to a fractionation procedure designed to enrich for 4-hydroxy-3-iodo-5-nitro-phenylacetyl (NIP)- or DNP-specific B lymphocytes, which depended on adherence of specific cells to a layer of hapten-gelatin at 4 degrees C, recovery of bound cells by melting, and digestion of adherent antigen by collagenase. A population of cells resulted which contained 90% typical B cells and 37% of cells capable of binding a fluorescent, haptenated polymeric protein. Fractionated cells were reacted in vitro with fluorescent conjugates of the specific haptens with polymerized flagellin [NIP-polymerized flagellin (POL)-tetramethylrhodamine isothiocyanate conjugate or DNP-POL-fluorescein isothiocyanate conjugate] under a variety of conditions, with the aim of investigating the behavior of Ig receptors on B lymphocytes after exposure to antigen; Experiments were performed with immunogenic and tolerogenic concentrations of antigen. Furthermore, four experimental designs were used, namely: (a) brief labeling with fluorescent antigen followed by culture without antigen (pulse design); (b) culture in the continuous presence of fluorescent antigen (continuous-labeling design); (c) culture in the continuous presence of nonlabeled antigen followed by labeling of unoccupied receptors by fluorescent antigen (receptor status design); and (d) culture with nonlabeled antigen for 2 h followed by incubation without further antigen for 20 h and labeling with fluorescent antigen (modulation design). Further insight into receptor occupancy and distribution was gained by the use of fluorescent antihapten and antiglobulin reagents. It was found that both immunogenic and tolerogenic antigen concentrations caused rapid patching and capping of the receptors to which they attached, followed by endocytosis and probably some shedding of Ig receptors. However, a proportion of cells continued to bear some cell surface antigen for 24 h. The immunogenic antigen concentration failed to completely remove the receptor coat from the cell surface. At all stages of immunogenesis, plentiful unoccupied receptors could be demonstrated. The tolerogenic concentration nearly saturated available receptors, and in its continuous presence, only few unoccupied or antigen-occupied surface receptors could be detected after 24 h of culture. Experiments of the modulation design showed that brief incubation with the tolerogenic concentration appeared to suppress receptor resynthesis, as few new receptors could be demonstrated after 20 h of further culture without antigen. Experiments were performed to determine whether fractionated cells prepared from spleens of 8-day-old mice showed an unusual tendency for modulation, even with immunogenic antigen concentrations. They were found to behave essentially like adult fractionated cells. The results are discussed in the framework of current theories of B-lymphocyte activation and tolerization.

Animals↗
PubMed1976

The specificity of cellular immune responses II. The structure of antigenic determinants leading to T-lymphocyte stimulation.

T cells from guinea pigs immunized with the hapten 2,4-dinitrophenyl (DNP)-coupled directly to mycobacteria are of interest since they recognize and respond to DNP conjugated to many but not all carriers. The experiments reported here further analyze the structure of the complex, chemically defined antigenic determinants recognized by such T cells. These antigenic determinants can have DNP coupled either to the xi-amino group of lysyl residues or to the hydroxyl group of tyrosyl residues. Furthermore, essential contributions to the determinant recognized by such T cells are made by amino acid residues to which the hapten is not attached. Such residues are thought to be close to the hapten group itself, since introducing a small spacer between hapten and carrier prevents recognition. The hapten itself is also recognized and discriminated from other haptens with great precision by these T lymphocytes. The strain of guinea pig immunized affects the precise specificity characteristics of the responding T cells, in a way that may reflect the activity of histocompatibility-linked immune response genes. Finally, the characteristics of the immunogen have been studied. It is thought that the lipid content of the mycobacteria may be critical in inducing the hapten-reactive T cells, and this is supported by finding similar responses in T cells from guinea pigs immunized with DNP protein to which lipid has been covalently attached. Thus, the T-cell population being studied, while recognizing haptens with great precision, appears to require a larger determinant for activation than do hapten-specific B lymphocytes.

Animals↗
PubMed1991

The effect of antibody isotype and antigenic epitope density on the complement-fixing activity of immune complexes: a systematic study using chimaeric anti-NIP antibodies with human Fc regions.

A systematic study has been carried out to investigate the role of immunoglobulin isotype, epitope density, and antigen/antibody ratio on the capacity of immune complexes to activate the classical and alternative pathways of human complement and for the complexes subsequently to bind to erythrocyte C3b-C4b receptors (CRI). For this purpose, a series of chimaeric monoclonal anti-NIP antibodies was used, which all shared the same combining site but had different human constant domains. Antigen epitope density was varied by coupling different numbers of NIP hapten molecules to bovine serum albumin. All three parameters affect complement fixation. In general, complement activation is better in antibody excess and at equivalence than it is in antigen excess, and better at high epitope density than at low epitope density, although the effects are variable for different immunoglobulin isotypes and for the two pathways. It has been confirmed that IgG1 and IgG3 are good activators of the classical pathway and are tolerant to variations in both epitope density and antigen/antibody ratio. IgG4 and IgA do not activate the classical pathway in any circumstances. IgG2 activates the classical pathway only at high epitope density and at equivalence or antibody excess. IgM activates the classical pathway well only at the higher epitope densities and at equivalence or antibody excess but, in addition, shows an interesting and unexpected prozone phenomenon where immune complex in antibody excess inhibits complement activation by the classical pathway. The results of the alternative pathway activation are strikingly different. IgA is by far the best activator of the alternative pathway and is relatively tolerant to epitope density and to antigen/antibody ratio. IgM, IgG1 and IgG3 do not significantly activate the alternative pathway in any circumstances. IgG2 is the best IgG subclass for alternative pathway activation but requires high epitope density and equivalence or antibody excess. Binding to CR1 in general parallels the amount of complement fixed independent to the pathway by which it is fixed. However, IgG1 and IgG3 complexes in antigen excess activate complement well but bind poorly to CR1. Nascently formed complexes seem to bind complement in a way that is similar to that bound by preformed complexes, but are then less able to bind to red cell CR1. These observations help to explain the pathogenesis of complement activation in various autoimmune and immune complex diseases such as systemic lupus erythematosus, autoimmune thyroiditis and others.

Animals↗
PubMed1976

The role of B-cell memory in secondary IgG and IgM responses.

Mice were primed with the hapten 3-nitro-4-hydroxy-5 iodophenacetic acid (NIP) conjugated to chicken globulin (cg) and were boosted 2, 6, or 12 months later with CG conjugates of the related haptens 3,5-diiodo-4-hydroxyphenacetic acid (DIP) or 3-nitro-4-hydroxphenacetic acid (NP). Accelerated secondary responses were demonstrated both in the 7S and 19S class. Fine-specificities of secondary-response antibodies were studied by the hapten inhibition method of haptenated bacteriophage inactivation. 7S antibodies were found to have the fine-specificity of anti-NIP antibodies regardless of whether DIP or NP was the booster hapten ('original antigenic sin'). 19S antibodies had the fine-specificity of anti-DIP when DIP was the booster hapten. NP as the booster hapten resulted in 19S antibodies whose fine-specificity was intermediate between anti-NIP and anti-NP. A strong B-cell memory could thus be demonstrated in the 7S antibody response and a weak B-cell memory in the 19S antibody response.

Animals↗
PubMed1976

IgA in secondary anti-hapten responses in vitro.

Production of IgA anti-hapten antibodies in vitro was studied in suspension and fragment cultures of spleens from mice immunized with NIP-CG (4-hydroxy-5-iodo-3-nitrophenylacetyl coupled to chicken globulin) a few weeks earlier. IgA anti-hapten production tended to be of much shorter duration than IgG anti-hapten production. IgA produced in fragment cultures had sedimentation coefficients of 9S, 11S, and 13S. 9S IgA anti-hapten was more prominent later during the in vitro response than earlier. In suspension cultures IgM anti-hapten production preceded IgA and IgG anti-hapten production. Very little IgM anti-hapten was seen in fragment cultures, although the responses on a cell-to-cell basis tended to be much higher in fragment than in suspension cultures.

Animals↗
PubMed1979

T helper lymphocytes recognize the VL domain of the isologous mouse myeloma protein 315.

The localization of a major determinant on an isologous myeloma protein (M315) which stimulates BALB/c helper T cells was investigated. Augmentation of the adoptive secondary antibody response to NIP-M315 and the idiotype of M315 (Id315) was used as an indicator of helper effects. Spleen cells primed with the light chain of M315 (L315) and its V-domain (VL315) were highly efficient helpers; priming with the fragment containing the two V-domains of M315 (FV315) induced a somewhat weaker helper effect than L315 or VL315. The helper effect was abolished or markedly reduced by treating the primed cells with rabbit anti-brain theta + C. Cells primed with the heavy chain of M315 (H315) effected weak but significant help. The V-domain of H315 (VH315) was incapable of eliciting cells with detectable helper effect. The data indicate that the VL315 embodies a major determinant for T helper lymphocytes. This determinant is expressed on the free VL315 as well as on the complete M315. In contrast, previous studies have shown that BALB/c antibodies produced against Id315 recognize antigenic sites that are only displayed on associated (VL315 + VH315) domains.

Animals↗
PubMed1976

The specificity of T lymphocyte responses to chemically defined antigens.

A system is described that allows the definition of T cell receptor specificity with some precision. It involves immunization of guinea pigs with hapten coupled to mycobacteria. The T cells of such animals respond to many but not all carriers modified by that hapten. Such T cells recognize neither hapten nor carrier alone, but rather determinants involving both the hapten and the carrier. No evidence for hapten-specific T cells was found. A model of the antigen binding site of the T cell receptor emerged from these experiments. According to this model, the T cell receptor consists of a single site of relatively large extent involving multiple subsites which are of low and roughly equal affinity. Thus, the haptenic group is not immunodominant for T cells as it is for B cells and for anti-hapten antibody. This suggests that the antigen binding receptor on T cells differs in some fundamental way from that on B cells. It is proposed that antigen recognition by T cells is mediated by an immunoglobulin heavy chain variable region that is not paired with an immunoglobulin light chain variable region.

Animals↗
PubMed1977

Immune response in mice to hapten conjugated sepharose.

Mice were injected intraperitoneally with Sepharose 4B beads coupled with hapten NIP, and their anti-NIP response was studied by counting antibody forming cells and determining serum titers. Mice responded well to doses of 0.7 ml of packed beads but 0.3 and 1.2 doses induced much weaker responses. Anti-NIP titers in recipients of 0.7 ml of the antigen lasted nearly constant for at least 7 weeks. Both T cell status of the recipient and use of adjuvant had an effect on the response. Antigen without adjuvant induced primarily IgM antibodies in normal mice, but IgM and IgG in nude mice. When Hemophilus pertussis or polyacrylic acid was used as adjuvant both normal and nude mice produced IgM and IgG antibodies, and normal mice produced in addittion IgA antibodies.

Adjuvants, Immunologic↗
PubMed1975

Specifically cytotoxic human and mouse lymphoid cells induced with antibody or antigen-antibody complexes.

Human or mouse lymphoid cells could be "armed" with anti-NIP antibodies to become cytotoxic to NNP-conjugated fowl erythrocytes (NNP and NIP are closely related haptens). The arming factor was neutralized by a sufficient concentration of NIP-BSA (twice the concentration causing maximal precipitation) but low concentrations (e.g., 7% of the maximal precipitation concentration) increased the arming capacity.

Animals↗