Scratching behavior in spontaneous- or allergic contact-induced dermatitis in NC/Nga mice

NC/Nga mice have pathological and behavioral features similar to those seen in human atopic dermatitis. There are two known dermatitis models in NC/Nga mice, one being spontaneous-induced dermatitis under conventional conditions and the other 2,4,6-trinitrochlorobenzene (TNCB)-induced allergic contact dermatitis. However, there are significant differences in time course on development of dermatitis. We studied the role of scratching behavior (sign of itch) on the development of dermatitis on spontaneous- and TNCB-induced dermatitis. We measured scratching counts, transepidermal water loss (TEWL), and skin inflammation score, under conventional conditions or by applying 5% TNCB once a week for 6 weeks in NC/Nga mice. In spontaneous-induced dermatitis, scratching counts increased with the passage of time. The scratching counts were significantly increased only 1 week after housing the mice under conventional conditions, but no changes were observed in cases of TNCB-induced dermatitis. In spontaneous-induced dermatitis, TEWL and skin-inflammation score were gradually increased, time-dependently. On the other hand, in TNCB-induced dermatitis, these dependent values rapidly increased and reached a maximum only after 24 h TNCB application. These data suggest that pathogenesis of spontaneous- and allergic contact-induced dermatitis was clearly different. It will be of major interest to identify the pruritic mediators causing profound scratching behavior and scratching-induced aggravation of inflammation in the spontaneous-induced dermatitis, as opposed to the inflammatory mediators that cause contact allergic dermatitis without major scratching.

Canonical germinal center B cells may not dominate the memory response to antigenic challenge

Spleen and bone marrow (BM) are the major sites of antibody production and anamnestic response in systemically immunized mice. We examined the VDJ segment repertoire of antibody plaque-forming cells (APFC) in those two sites in the course of antibody responses to the hapten nitrophenyl (NP). Individual IgG APFC expressed any one of 10 V(H) segments of the V186.2/V3 (J558) gene family: 186.2, 102, 23, C1H4, 165.l, CH10, 3, 593.3, 24.8 and 671.5. The majority of cells in both spleen and BM expressed the V186.2 gene joined to a D segment with Tyr95. During a 2-month period after a single immunization, the V186.2(+) APFC in BM accumulated 3 times as many somatic mutations than splenic APFC (average 8.5 versus 3 mutations/V(H)); this process was T(h) dependent as shown by in vivo depletion of CD4(+) lymphocytes. However, the V186.2(+) APFC in both spleen and BM shared a recurrent W33L replacement, indicating their common origin from germinal centers. The APFC expressing the other (analogue) V(H) segments were evenly represented in the spleen and BM, but they accumulated few, if any, mutations. The anamnestic V186.2(+) APFC were highly mutated both in the spleen and BM; they represented a new and unexpected clonotype. The V/D segments were joined by Gly95 instead of Tyr95, the W33L was absent and a new shared K58R replacement appeared. The APFC expressing the 'analogue' V(H) genes comprised approximately 20% of the anamnestic response and did not accumulate more mutations, but their affinities were in the range of the memory V186.2(+) cells. These data suggest that the late primary and secondary responses to a hapten may be born by different B cell lineages, and that some clonotypes may reach the memory pool without an extensive mutation and expansion.

Exploitation of a monoclonal antibody for weak affinity-based separation in capillary gel electrophoresis

Weak biospecific recognition has been established for affinity separation in high performance liquid chromatography (HPLC). The use of weak affinity chromatography (WAC) has been limited previously by the insufficient separation efficiency achieved, allowing only some 1000 plates/m to be obtained. However, it has been shown that chiral drug separation can be performed with capillary affinity gel electrophoresis (CAGE) at considerably improved efficiency as compared with traditional chromatographic procedures. Our present study demonstrates the potential of weak affinity monoclonal antibodies as a generic method for immunologically based separations in capillary electrophoresis. Monoclonal antibodies were polymerized within a silica capillary and were used for the separation of structurally similar carbohydrate antigens. The results indicate that weak biospecific interactions can be utilized in a CAGE format to produce highly selective separation of the alpha- and beta-forms of p-nitrophenyl-labeled maltose. It remains to be seen, however, how efficient weak affinity separation in CAGE can be compared with affinity HPLC protocols. Details of typical separations and of the preparation of the antibody gel are presented.

Contact allergens and epidermal proinflammatory cytokines modulate Langerhans cell E-cadherin expression in situ

After exposure to antigen, Langerhans cells (LC) migrate from the epidermis to lymph nodes, where they initiate primary immune responses in T cells. The adhesion molecule E-cadherin mediates adhesion of LC to keratinocytes in vitro and may be responsible for localization of LC in epidermis. To determine if levels of LC E-cadherin are modulated during LC emigration from epidermis, we utilized flow cytometry to evaluate E-cadherin expression on BALB/c LC exposed in situ to the contact allergen 2,4,6-trinitrochlorobenzene (TNCB). TNCB induced increased I-A/E antigen and decreased E-cadherin expression on a subpopulation of LC as early as 12 h, and as late as 48 h, after application. At 24 h, approximately 30% of LC in TNCB-treated skin expressed increased I-A/E antigens; of these activated LC, approximately 40% expressed decreased levels of E-cadherin. E-cadherin levels on this latter subset were approximately 15% of those expressed by LC in normal skin, and were similar to levels on cultured LC and LC that migrated from skin explants. The effect was specific for allergens; no changes occurred in LC following treatment with several contact irritants or the tolerogen dinitrothiocyanobenzene. To determine if cytokines modulated LC E-cadherin expression, we introduced various cytokines into BALB/c ear skin and assayed I-A/E antigen and E-cadherin levels. Of the cytokines tested, only interleukin-1 and tumor necrosis factor alpha reproduced the effects of TNCB. We propose that downmodulation of E-cadherin expression occurs as a consequence of local cytokine production during antigen-induced LC activation, facilitating LC emigration and the initiation of immune responses against antigens encountered in epidermis.

Lipopolysaccharide from Brucella abortus behaves as a T-cell-independent type 1 carrier in murine antigen-specific antibody responses

In order to determine the carrier nature of lipopolysaccharide from Brucella abortus (LPS-BA) in evoking humoral responses, normal and immunodeficient mice were immunized with trinitrophenyl (TNP)-conjugated LPS-BA (TNP-LPS-BA) and the responses were compared with those to known T-dependent and T-independent antigens. TNP-LPS-BA, like T-independent type 1 (TI-1) antigens such as TNP-BA and TNP-LPS from Escherichia coli (TNP-LPS-EC), generated anti-TNP responses in BALB/c, athymic BALB/c nu/nu, and CBA/N mice. In contrast, N-2,4-dinitrophenyl-beta-alanylglycylglycyl-substituted keyhole limpet hemocyanin, a typical T-dependent antigen, was not immunogenic in athymic mice, and TNP-Ficoll (T-independent type 2) was ineffective in eliciting humoral responses in CBA/N mice. These results indicate that LPS from B. abortus acts as a TI-1 carrier in generating antibody responses. In C3H/HeJ mice, TNP-LPS-BA generated higher-titer immunoglobulin G1 (IgG1), IgG2a, and IgG2b anti-TNP antibodies than TNP-LPS-EC. Compared with those from BALB/c mice, pure resting B cells isolated from C3H/HeJ mice exhibited a 30-fold lower proliferative response to LPS-EC, whereas the LPS-BA response was reduced to a lesser extent (5-fold). This suggests that the disparity observed in antibody titers was due to different abilities of LPS from B. abortus and E. coli to stimulate C3H/HeJ B cells. The ability of LPS from B. abortus to act as a carrier in generating humoral immune responses indicates that LPS-BA can be substituted for whole B. abortus organisms in vaccine development.

Human IgG subclass pattern of inducing complement-mediated cytolysis depends on antigen concentration and to a lesser extent on epitope patchiness, antibody affinity and complement concentration

The relative complement-mediated lytic capability of the IgG subclass isotypes was studied using a matched set of mouse-human chimeric anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) antibodies. The subclass pattern was shown to be highly dependent on variations in antigen concentration and to lesser extent on variation in epitope patchiness, antibody binding affinity and complement concentration. In general, the IgG3 subclass was most effective in inducing cytolysis at the different conditions used and only at high antigen concentration did the IgG1 subclass mediated more efficient cytolysis than IgG3. The IgG2 isotype required a relative high antigen concentration to be cytolytic while the IgG4 isotype was not cytolytic at any of the conditions tested. These individual characters of each of the IgG subclasses makes it conceivable that a subtle system of immunoregulation exists among the subclasses.

Thymus-dependent antiidiotype and anti-antiidiotype responses to a dinitrophenyl-specific monoclonal antibody

BALB/c mice were inoculated i.p. with graded doses of a DNP-specific, IgM mAb (designated 57.1). Injection with unmodified 57.1 in the absence of adjuvants resulted in the generation of an anti-Id response (Ab2) and an anti-anti-Id response (Ab3). The generation of serum anti-Id antibodies was found to be thymus dependent. Nude mice immunized with 57.1 were unable to produce a serum Ab2 response above nonimmunized controls whereas euthymic mice receiving identical doses of 57.1 produced strong Ab2 responses. To examine the specificity of serum anti-Id, sera from mice receiving 57.1 were screened against a panel of mAb representing at least five distinct VH gene families. Serum titers were significantly higher against 57.1 than against any of the other antibodies in the panel. Three of the antibodies in this panel bind FD5-1, a monoclonal anti-Id (Ab2) that also binds 57.1. However, sera from mice receiving 57.1 bound 57.1 only. Thus, the serum Ab2 response appears to be highly specific for idiotopes on 57.1. The predominant isotype of these anti-Id antibodies was IgG1. The number of isotypes detected increased in a dose dependent manner with all IgG subclasses having anti-Id specificity in sera from animals receiving the higher doses of 57.1. Further analysis of the serum demonstrated that approximately 8% of the Ab2 response was paratope-specific (inhibitable by the monovalent hapten DNP-lysine). The same sera were analyzed for the presence of Ab3 by binding to the monoclonal anti-Id antibody FD5-1. Lower serum titers of Ab3 were generated in comparison to serum titers of Ab2. Analysis of the binding specificity of the Ab3 response revealed that DNP-BSA was able to partially inhibit the binding of serum IgM and IgG Ab3 to FD5-1. A subset of the Ab3 response. Ab1' that is specific for DNP was observed in a direct binding assay where detectable amounts of DNP binding IgM, IgG1, and IgG3 isotypes were present. We have thus described a complete circuit (Ab1----Ab2----Ab3) of antibodies within the Id network by immunizing animals with an unmodified mAb in the absence of Ag or adjuvants.

Alteration of idiotypic connectivity in prenatally tolerized neonatal mice

Prenatal tolerization with trinitrobenzenesulphonic acid (TNBS) leads to expansion of trinitrophenyl (TNP)-specific B cells, the majority of which become refractory to stimulation during postnatal development. One possible explanation could be that they belong to the repertoire of naturally activated B cells which are limited in expansion after antigenic stimulation due to a high degree of idiotypic connectivity. To evaluate this hypothesis, 59 thymus- and 490 spleen-derived B-cell hybridomas from 6-day-old prenatally untreated and prenatally TNBS-treated mice were tested for reactivity against 33 arbitrarily chosen clones derived from the same fusions, 17 being derived from control and 16 from tolerized litters. Two major points could be deduced: (1) Idiotypic connectivity, including connectivity of TNP- and anti-TNP-reactive monoclonal antibodies (MoAb), was maintained after prenatal tolerization. This accounted for thymus- and spleen-derived MoAb. (2) Only TNP- and anti-TNP-reactive MoAb derived from prenatally untreated and prenatally tolerized mice displayed significantly distinct idiotypic profiles. Differences were pronounced, especially with thymus-derived MoAb. Thus, TNP-specific B cells in prenatally tolerized newborns do not behave like B cells of adult mice stimulated by external antigen, but rather like a part of the naturally activated, idiotypically connected B-cell repertoire of the newborn. This could explain B-cell unresponsiveness at older age as a consequence--at least partly--of their high idiotypic connectivity.

Anti-TNP antibody localization of the reactive lysine residues in myosin

Myosin contains reactive lysine residues which are trinitrophenylated by 2,4,6-trinitrobenzene sulfonate much faster than the rest of the lysines. Here we find the location of these residues in the primary and spatial structure of myosin with the help of an anti-trinitrophenyl antibody. This antibody was raised against trinitrophenyl hemocyanin in rabbits. It reacted with trinitrophenylated myosin, and with some of the tryptic fragments of trinitrophenylated myosin. By analyzing the reaction with Western blots, it was found that the antibody preferentially reacts with the 27 kDa N-terminal fragment of the myosin head, and more weakly with the light meromyosin region of the myosin rod. The 27 kDa fragment contains the most reactive lysine residue, while the intermediate lysine residue is located in the light meromyosin region. The locations of the epitopes of the antibody were visualized on electron microscope images of rotary-shadowed trinitrophenylated myosin-antibody complexes. The distances of the epitopes to the head-rod junction of myosin were measured as 13 and 113 nm for the epitope on the head (reactive lysine residue) and for that on the rod (intermediary reactive lysine residue), respectively.

Intrathymic T cell repertoire after prenatal trinitrobenzene-sulfonic acid-treatment

It is still a matter of debate, whether tolerance toward self-non-MHC antigens is due to intrathymic deletion or to regulatory processes in the periphery. To further pursue this question, responsiveness toward TNP and an anti-TNP monoclonal antibody (Sp6) carrying a recurrent idiotype was evaluated in prenatally trinitrobenzenesulfonic acid (TNBS)-treated mice. In prenatally untreated as well as in TNBS-treated mice, thymocytes proliferating in the absence of nominal antigen were double negative (L3T4-/Lyt2-), but antigen-specific thymocytes were single positive (L3T4+/Lyt2- or L3T4-/Lyt2+). TNBS-treated mice differed from controls inasmuch as in their first week of life T cells proliferating in response to TNP were found in the thymus and detected at increased frequencies in the spleen. The frequency of TNP-specific thymocytes and spleen cells declined rapidly, finally reaching in the spleen a level of 20-30% of controls. Furthermore, after antigenic stimulation, the frequency of thymocytes and spleen cells proliferating in response to TNP was found to be increased in control mice, but TNP-specific T cell were no more recovered in the thymus or the spleen of tolerized mice. The same accounted for thymic and splenic T cells proliferating in response to Sp6. They were expanded in control mice after antigenic stimulation, but were undetectable in TNBS-treated mice. Thus, T cells with specificity for an internal (Sp6) and an external (TNP) antigen, provided the latter was present during ontogeny, were detected in the thymus of control and, transiently, in the thymus of tolerized mice. But, the fate of antigen-specific thymocytes was different in prenatally untreated and TNBS-treated mice. The data are interpreted in the sense that tolerance toward non-MHC antigens may be acquired subsequently to tolerance toward self-MHC antigens and possibly after imprinting of antigen specificity.

Anaphylactic properties of monohaptenic dinitrophenylated tripalmitoyl-S-glyceryl-cysteinyl lipopeptides

Tripalmitoyl-S-glycerylcysteinyl lipopeptides are B-cell and macrophage activating and may be used as low molecular weight immunogens of considerable potency and even as vaccines when conjugated with suitable epitopic structures. Selected lipopeptides carrying single Dnp haptens were found to evoke mild passive cutaneous anaphylaxis in guinea pigs sensitized against Dnp. The reactions were observed after intravenous injection whereas intradermally applied antigen was negative. The anaphylactogenicity seems unrelated to micelle or aggregate formation of the insoluble peptides which require lecithin additions as well as sonication to become solubilized. The dinitrophenylated lipopeptide tripalmitoyl-S-glyceryl-cysteinyl-seryl-lysine produced toxic reactions which were not observed with the lipopeptide devoid of Dnp. Dinitrophenylated tripalmitoyl-S-glycerylcysteiny-1,6-diaminohexane and tripalmitoyl-S-glyceryl-cysteinyl-lysine did not show these toxic reactions.

Influence of glutathione conjugation on the immunogenicity of dinitrophenyl derivatives in the rat

The role of metabolic detoxication (glutathione conjugation) in the humoral response to three model haptens, dinitrofluorobenzene (DNFB), dinitrochlorobenzene (DNCB) and dinitrobenzenesulphonate (DNBS), was investigated in male Wistar rats. All three haptens produced a measurable anti-dinitrophenyl IgG antibody response over a wide dose range (2.7 nmol/kg to 0.27 mmol/kg) given for 4 days. A significant difference in antibody titre was only observed at the highest dose (DNFB greater than DNCB = DNBS), despite a marked difference in reactivity towards a protein carrier (albumin) and N-acetyl-lysine in vitro. These observations can be partly explained by the fact that the most reactive hapten (DNFB) conjugates most rapidly with glutathione in vitro and in vivo.

The specific interaction of helper T cells and antigen-presenting B cells. IV. Membrane and cytoskeletal reorganizations in the bound T cell as a function of antigen dose

We have used double-immunofluorescence labeling to determine the surface distributions of LFA-1 and CD4, and the intracellular distributions of the cytoskeletal protein talin and of the microtubule organizing center (MTOC) of cloned Th cells in 1:1 cell couples with antigen (Ag)-specific APC of the B cell type (B-APC). The Th cell was directed to a peptide fragment of the Ag OVA in the context of IAd. The B-APC was the transfected A20 B hybridoma cell A20-HL, bearing on its surface a surface Ig specific for the hapten TNP, and pulsed with different concentrations of DNP-OVA. At sufficiently high doses of DNP-OVA (greater than 100 ng/ml), in essentially all couples, LFA-1, CD4, and talin were each concentrated at the Th cell membrane where it was in contact with the B-APC, and the MTOC inside the Th cell was reoriented to face the contact region. At lower doses of DNP-OVA (between 50 and 10 ng/ml), in all couples, LFA-1 and talin were concentrated at the Th/B-APC contact region, but the extent of CD4 clustering, MTOC reorientation, and Th cell proliferation all decreased with decreasing Ag dose. With no Ag, none of these effects was observed. These and other data indicate that two distinct signals are received by the Th cell that is specifically bound to its B-APC. The first signal, at low Ag doses, stimulates a linkage of LFA-1 and talin in the Th cell, and a specific LFA-1-mediated intercellular adhesion; the second signal, at higher Ag doses, is required to induce Th cell proliferation, with which the Th-MTOC reorientation and CD4 clustering are correlated.

Production and characterization of T-cell clones specific for trinitrophenyl (TNP)-modified syngeneic spleen cells (TNP-self)

Using serial antigenic challenge as the method of selection and stimulation, continuous lines of cytotoxic T-lymphocytes (CTL) directed against TNBS-modified syngeneic spleen cells (TNP-self) have been generated. Spleen cells from C3H/HeJ (H-2k) mice were primed in vitro with autologous spleen cells modified with TNBS, and subsequently cloned by limiting dilution and in soft agar in the presence of IL2. These CTL clones grew continuously in medium supplemented with IL2 and in the presence of antigen. They are antigen specific and H-2 restricted in their target cell recognition. They all express Thyl and Lyt2 surface markers. None of the clones exhibit natural killer (NK) cell activity. All CTL clones tested so far are restricted in their target cell recognition to H-2Kk-TNP and none were found to be restricted to H-2Dk-TNP. These findings demonstrate at the clonal level the H-2K/D restriction of TNP-self specific CTL. These clones provide tools that may facilitate an understanding of the development and regulation of antigen specific CTL. They may also serve as models useful towards an understanding of the mechanism of lysis by CTL.

Antigen-specific inhibition of IL-2 and IL-3 production in contact sensitivity to TNP

The production of IL-2 and IL-3 by T cells from mice which had been contact sensitized to TNP and/or tolerized by intravenous injections of TNBS was assayed. Contact sensitization rapidly primes T cells, so that they respond to in vitro restimulation with haptenated syngeneic cells by producing IL-2 and IL-3. This production is strongly inhibited, in an antigen-specific manner, in tolerized mice. At least part of this inhibition can be attributed to the action of suppressor T cells that act by preventing the activation of lymphokine production in vitro. Lymphokine production thus closely parallels the in vivo delayed-type hypersensitivity (DTH) reaction in this system.

Hierarchy of cytotoxic T cell clones. I. Reversal of resistance to lysis and killing between anti-hapten cytotoxic T cells

Cells from clones of anti-hapten cytotoxic T lymphocytes (CTL) can act as both effector cells and, when treated with the specific hapten, as target cells. Individual clones can kill haptenated cells only from other clones that are less efficient killers. Clones specific for both fluorescein and trinitrophenol could be ordered in a single hierarchy in which resistance to lysis correlated with lytic efficiency. When the killing efficiency was reduced with phorbol myristate acetate (PMA) or the colchicine analogue, Colcemid, the degree of resistance to lysis was also reduced. The use of PMA-treated fluoresceinated targets greatly enhanced intraclonal killing and similarly lead to a repositioning of clones within the hierarchy of normal cells. By the haptenation of appropriate clones, efficient CTL could kill cells from other clones in a direction apparently opposite to recognition. The results demonstrate that effects other than antigen recognition of the target cell may result in variations in the nature of T cell immune responses.

Studies on active immunization with self antigens. II. Production of antibody related to hapten substitution

BALB/c mice were injected during neonatal life with conjugates in buffered physiological saline, prepared by coupling trinitrophenyl groups (TNP) at various densities to either syngeneic mouse serum albumin (TNP-MSA) or xenogeneic bovine serum albumin (TNP-BSA). Serum samples were obtained on days 30 and 60 after birth, on days 75 and 88 after two booster injections, and monoclonal antibodies were prepared from spleens of neonatally treated mice. The antibody titres, isotypes, and specificities were evaluated by enzyme-immunoassay. It was found that the extent of the anti-TNP immune response to TNP-MSA conjugates depends on the degree of hapten substitution, which is not the case for the anti-TNP-BSA. All the TNP-MSA conjugates induced mainly IgG and only a few IgM antibodies. These antibodies reacted essentially with the TNP group but seemed to have a higher avidity for the TNP-protein conjugate used in their induction. During the course of the immunization, decreasing quantities of TNP-MSA conjugates were needed to inhibit antibody binding. A large amount of monoclonal anti-TNP antibodies was found in hybridomas obtained after neonatal treatment either with TNP-MSA or TNP-BSA. Therefore, it appears that the anti-TNP immune response obtained after antigenic stimulation with sufficiently substituted TNP-MSA conjugates possesses all the characteristics of a normally occurring humoral immune response.

Natural anti-TNP antibodies from rainbow trout interfere with viral infection in vitro

Normal and viral-infected rainbow trout (RT) were tested for serum antibody activity against self and nonself antigens. Particularly high titres of anti-trinitrophenyl (TNP) antibodies were noted, as in other fish species. To analyse this, the anti-TNP antibodies were isolated by affinity chromatography and their capacity to interfere with viral infection in vitro was studied. We selected RT fibroblasts as target cells, and two common pathogenic viruses in trout, a rhabdovirus, viral haemorrhagic septicaemia virus (VHS) and a birnavirus, the infectious pancreatic necrosis virus (IPN). Anti-TNP antibodies were examined for their capacity to neutralize VHS and IPN viruses. Data obtained show that the anti-TNP antibodies, even at high concentrations, only partially neutralized virus. In contrast, when anti-TNP antibodies were assayed for their protective activity using RT fibroblast cells infected with VHS or IPN viruses, results showed high protective activity, regardless of serum origin or of the virus used, when the antibodies were added to the cell culture after viral infection. Therefore, our experiments indicate that the protective activity does not seem to be due to a direct interaction of the antibodies with the viruses. It is suggested that virus-modified cell surface self structures exhibit new epitopes which interact with the anti-TNP antibodies. Such an interaction would allow anti-TNP antibodies to participate in a non-specific defence mechanism against viral infection.

Marginal zone of the murine spleen in autotransplants: functional and histological observations in the response against a thymus-independent type 2 antigen

Splenic tissue from mice was autotransplanted; after initial necrosis, a rapid restoration of implants into a structure histologically indistinguishable from splenic tissue was observed. The development of the marginal zone in these autotransplants, as determined with monoclonal antibodies against different splenic cell types and routine histological stains, was compared with the local and systemic response against a thymus-independent (TI) type 2 antigen. Full restoration of time course and peak of anti-trinitrophenyl (TNP) serum titres against TNP-Ficoll was observed at 4 weeks after autotransplantation. Anti-TNP antibody-forming cells were observed in subnormal and normal numbers in 2- and 4-week old autotransplants, respectively. The appearance of normal numbers of antibody-forming cells, and the restoration of antibody titres at week 4 correlated with the return of newly formed B cells in a normal marginal zone. An unexpected observation was that marginal zone macrophages did not return until 10 weeks after transplantation, thereby making the necessity for these cells in the normal TI-2 response unlikely. We conclude that normal anti-TI-2 responses (onset and peak titres) can be restored by autotransplantation of splenic tissue. B cells and marginal zone organization are responsible for this response, for which marginal zone macrophages seem expendable. The partial protection against overwhelming post-splenectomy infections, given by autotransplants, can thus be explained by restorative capabilities of these implants on antigen presentation and antibody formation against TI-2 antigens, and not by an increase (compared with splenectomized individuals) of phagocytosis by marginal zone macrophages.

IL-1 and PGE2 productions by the regional lymph node cells from DNFB-sensitized mice

Interleukin 1 (IL-1) and Prostaglandin E2 (PGE2) are mainly produced by macrophage/monocytes. In this experiment, we investigated the immunological role of macrophage/monocytes in the lymph nodes (LNs) by measuring IL-1 and PGE2 productions of regional LN cells from dinitrofluorobenzene (DNFB)-sensitized and -tolerant mice. LN cells from sensitized mice produced IL-1 in remarkable amounts after in vitro antigen stimulation. On the other hand, the LN cells from tolerant mice failed to produce IL-1 or PGE2. These data indicate that, by modifying cytokine production, macrophage/monocytes in the regional LNs play a key role in the pathomechanism of contact hypersensitivity.

Role of interferon-gamma in the modulation of the IgE response by 2,4-dinitrophenyl-Bordetella pertussis vaccine in the mouse

Immunization of mice with 2,4-dinitrophenyl-Bordetella pertussis (DNP-BP) failed to induce anti-DNP IgE responses. Administration of DNP-BP induced, however, the formation of anti-DNP IgE B memory cells, as demonstrated by adoptive transfer. Furthermore, mice pretreated with DNP-BP and primed with 2 micrograms DNP-ovalbumin (OA) in alum 2 weeks later produced high day-7 anti-DNP IgE levels. These subsided to near undetectable levels by day 12-14. The transient expression of serum IgE levels was accompanied by normal levels of anti-DNP IgG. The anti-OA response induced as a result of priming with DNP-OA in alum was not affected by pretreatment with DNP-BP. IgG subclass analysis revealed that mice pretreated with DNP-BP had elevated levels of IgG2a and reduced levels of IgG1 as compared to control (TNP-keyhole limpet hemocyanin-pretreated) mice. Treatment of mice with an anti-interferon-gamma monoclonal antibody, shortly after immunization with DNP-BP, not only reduced anti-DNP IgG2a levels, but prevented the sharp anti-DNP IgE decline that occurred after priming with DNP-OA in alum. These results suggest that DNP-BP-induced interferon-gamma production modulates Ig isotype expression in vivo in an anti-gen-specific manner.

Primary in situ immune response in popliteal lymph nodes and spleen of mice after subcutaneous immunization with thymus-dependent or thymus-independent (type 1 and 2) antigens

Mice were immunized subcutaneously with thymus-independent (TI)-type 1 antigen trinitrophenylated lipopolysaccharide (TNP-LPS), TI-type 2 antigen TNP-Ficoll or thymus-dependent (TD) antigen TNP-keyhole limpet haemocyanin (TNP-KLH) in order to study the primary in situ immune response in popliteal lymph nodes (PLN) and spleen. The spleen responded more rapidly in developing specific antibody-forming cells (AFC) than the lymph nodes did, in spite of the fact that antigens reach the spleen only after passing several lymph node stations. This difference between lymph nodes and spleen in developing AFC was particularly significant with respect to the responses to TI (both type 1 and type 2) antigens. No differences in the distribution of specific AFC in PLN and spleen were observed after immunization with TI and TD antigens. Results are discussed with respect to the relative contributions of lymph nodes and spleen to immune responses to antigens injected subcutaneously.

Inhibition of cryoprecipitation of murine IgG3 anti-dinitrophenyl (DNP) monoclonal antibodies by anionic DNP-amino acid conjugates

Previously we have demonstrated that eight out of nine IgG3 monoclonal antibodies (mAb) obtained from autoimmune MRL-lpr/lpr mice were able to self-associate and to precipitate in the cold (Gyotoku et al., J. Immunol. 1987. 138:3785). To determine whether the cryoprecipitation of IgG3 mAb is enhanced or inhibited in the presence of specific ligand, we have established eight IgG3 mAb reactive with 2,4-dinitrophenol (DNP) hapten: four mAb were obtained from fusion of spleen cells of C57BL/6 mice immunized with 2,4,6-trinitrophenylated keyhole limpet hemocyanin, three from 129/Sv and one from BALB/c immunized with DNP-lipopolysaccharide. Five of them induced cryoglobulins composed exclusively of the IgG3 mAb. The binding of negatively charged monomeric DNP-amino acid conjugates completely inhibited the cryoprecipitation of all the five cryoprecipitating anti-DNP IgG3 mAb, while the incubation with positively charged or neutral DNP-amino acid conjugates had variable effects: increase, inhibition or no change of the cryoprecipitation. In addition, positively charged DNP-amino acid conjugates were able to induce the cryoprecipitation of one of the non-cryoprecipitating anti-DNP IgG3 mAb. Our data showed that (a) IgG3 mAb derived from non-autoimmune strains of mice, similar to IgG3 mAb derived from an autoimmune MRL-lpr/lpr strain, possessed the unique property to self-associate and were able to form cryoglobulins in most cases; (b) although the Fc-Fc interactions of IgG3 mAb play a decisive role in IgG3 cold solubility, IgG3 cryoprecipitation was markedly influenced after interacting with their specific ligand, depending on the charge of the hapten-amino acid conjugate. This suggested that even minor interferences with the electrostatic equilibrium of the IgG3 by the binding of charged hapten molecules induced dramatic changes in the solubility of the IgG3 mAb at low temperature.

Postnatal B cell development: influence of trinitrobenzenesulfonic acid treatment during pregnancy

Prenatal treatment with a reactive hapten may be well suited for analyzing the establishment of self tolerance because the hapten binds ubiquitously to proteins and cells and persists for a long period in the developing organism. Based on this consideration, pregnant BALB/c mice were treated with 2,4,6-trinitrobenzenesulfonic acid (TNBS), searching for differences in 2,4,6-trinitrophenyl (TNP) responsiveness in their offspring as compared to litters of untreated mice. The frequency of TNP-specific T-independent B cells of litters from TNBS-treated mothers was very low at birth and remained below 10% of controls until the age of 42 days. On the contrary, in 8-day-old prenatally TNBS-treated litters, the frequency of TNP-specific T-dependent B cells was higher than in controls. Expansion of TNP-specific B cells after antigenic stimulation of control mice started at the age of 3-4 weeks and expansion rates increased with age, while in prenatally TNBS-treated mice, significant expansion rates were seen at the age of 2 weeks only. Yet, after restimulation with TNP-lipopolysaccharide or with a TNP-anti-TNP conjugate, but not after restimulation with TNP-ovalbumin, similar numbers of plaque-forming cells (PFC) were observed with spleen cells of prenatally untreated and TNBS-treated mice, the latter revealing an exceptional predominance of IgG PFC. Thus, TNP-specific B cells were not deleted, but prenatal TNBS treatment resulted in an altered composition of TNP-specific B cell subpopulations, their regulation differing qualitatively from the one observed in prenatally untreated mice.

Inverse relationship between proliferation and differentiation in a human TNP-specific B cell line. Cell cycle dependence of antibody secretion

Studies of an EBV-transformed and TNP-specific human B cell line revealed that, unlike myeloma or hybridoma cell lines that consist mainly of fully differentiated cells, most of the cloned EBV-transformed cells were not fully differentiated, as judged by inability to bind TNP-SRBC and to secrete anti-TNP antibody. The minority of more differentiated cells were selected by TNP-SRBC rosetting. They were found to proliferate to a lesser extent than nonrosetting cells and to contain increased numbers of antibody-secreting cells. This inverse relationship between proliferation and differentiation was also shown to be cell cycle related in that the TNP-SRBC rosetting cells resided, to a greater extent than the nonrosetting cells, in the G1 phase of the cell cycle. The finding that the G1 phase of the cell cycle was associated with differentiation into anti-TNP secreting cells was confirmed by demonstrating that treatment with hydroxyurea, which arrests the cells in G1, resulted in decreased proliferation and an increased proportion of antibody-secreting cells. Similarly, addition of phorbol ester resulted in increased antibody secretion and decreased proliferation, suggesting a role for protein kinase C in this differentiation pathway. The strategy of increasing the number of antibody-producing cells in this human EBV line, by promoting differentiation of the cells in G1, may be relevant to the large scale production of specific human mAb for the treatment and diagnosis of human diseases.

A map of VH genes located next to the DH region in the Igh locus of two congenic Igh-recombinant mouse strains

A new congenic mouse strain (C57BL/6-Igh-Vb-Ca) with a recombinant chromosome 12 is described. It carries the Igh-1a allele, but shows the serological characteristics of C57BL/6 when analyzed for idiotype expression with respect to the antigens dextran and (4-hydroxy-5-iodo-3-nitrophenyl)acetyl (NIP). We analyzed liver DNA from one animal for restriction fragment length polymorphism by hybridization to probes detecting members of nine VH gene families and DH segments, and compared it to DNA from animals carrying the nonrecombinant haplotypes Igha and Ighb, respectively. The breakpoint of recombination maps to the region carrying members of VH gene families VGAM3.8, PC7183 and Q52. The CB8KN strain which according to the serological analysis carries a recombinant Igh locus (Igh-Va-Cb) on BALB/c background was also analyzed. In this strain the breakpoint of recombination again maps to the region carrying members of VH gene families VGAM3.8, PC7183 and Q52. Our results show that the VH genes of families PC7183 and Q52 are interspersed and map to the region next to the DH locus. At least one gene from the VGAM3.8 family also maps to this region in the Igha and the Ighb haplotype.

IgD antibodies to DNP are specifically induced in ascitic fluid after intraperitoneal immunization

The induction characteristics of IgD in serum and other body fluids are poorly understood. Here we report that Freund's complete adjuvant (FCA), when used in intraperitoneal (i.p.) immunization, resulted in significantly higher levels of IgD and specific IgD antibodies in ascitic fluid than in the serum of the same animals. This was in sharp contrast to the distribution of IgM and kappa light chain-bearing immunoglobulins (kappa Ig) between these compartments. Female rats were immunized subcutaneously (s.c.) on Day 0 with 1:1 FCA mixed with either 2,4 dinitrophenyl group A streptococcal vaccine (DNP-GASV), 2,4 dinitrophenyl ovalbumin (DNP-OVA), or saline. A week later (and weekly thereafter) they were boosted i.p. with these antigens mixed with FCA 1:9. Eleven of sixteen rats produced some ascites by Day 21, and 15/16 by Day 28. Total immunoglobulin and specific antibodies for the heavy-chain isotypes IgD and IgM and for kappa Ig were measured by ELISA. Between immunization groups no significant differences were observed in total immunoglobulin levels. Subcutaneous immunization with 1:1 FCA caused a significant two- to six-fold increase in serum IgD by Day 7 (P less than 0.01), while no change occurred with serum IgM or kappa Ig. Ascitic fluid collected on Day 21 had significantly high levels of IgD than that of serum IgD (P less than 0.01), with a mean level nine times that of the serum. In contrast, levels of total IgM, kappa Ig and total protein were significantly lower in ascitic fluid than in serum (all P less than 0.05). The high levels of IgD in ascitic fluid disappeared in Day 28 ascitic fluid, while IgM and kappa Ig levels were relatively unchanged. The ratio of ascitic fluid to serum IgD anti-DNP was 9.8 for the DNP-GASV-immunized group on Day 21, and 23.9 for the DNP-OVA-immunized group on day 28. The same ratios for IgM anti-DNP and kappa Ig anti-DNP were much lower, ranging from 0.4 to 2.3 and 0.3 to 3.3, respectively.

Sequences of 12 monoclonal anti-dinitrophenyl spin-label antibodies for NMR studies

Eleven monoclonal antibodies specific for a spin-labeled dinitrophenyl hapten (DNP-SL) have been produced for use in NMR studies. They have been named AN01 and AN03-AN12. The stability constants for the association of these antibodies with DNP-SL and related haptens were measured by fluorescence quenching and ranged from 5.0 X 10(4) M-1 to greater than 1.0 X 10(8) M-1. cDNA clones coding for the heavy and light chains of each antibody and of an additional anti-DNP-SL monoclonal antibody, AN02, have been isolated. The nucleic acid sequence of the 5' end of each clone has been determined, and the amino acid sequence of the variable regions of each antibody has been deduced from the cDNA sequence. The sequences are relatively heterogeneous, but both the heavy and the light chains of AN01 and AN03 are derived from the same variable-region gene families as those of the AN02 antibody. AN07 has a heavy chain that is related to that of AN02, and AN09 has a related light chain. AN05 and AN06 are unrelated to AN02 but share virtually identical heavy and light chains. Preliminary NMR difference spectra comparing related antibodies show that sequence-specific assignment of resonances is possible. Such spectra also provide a measure of structural relatedness.

A hemagglutinin of uropathogenic Escherichia coli recognizes the Dr blood group antigen

A receptor moiety and blood group substance recognized by the O75X adhesin was studied. Well-defined erythrocytes representing different blood group systems and bacterial derivatives carrying plasmid pBJN406 encoding the adhesin were used in a direct hemagglutination assay. We showed that Dr blood group antigen, a component of the IFC blood group complex, is the receptor for the O75X fimbrialike adhesin (Dr hemagglutinin) of uropathogenic Escherichia coli. The molecule recognized by the Dr hemagglutinin on Dr blood group substance is a chloramphenicol-like structure. The inhibitory effect of the active compounds indicates that a tyrosine-containing molecule could be a natural receptor for the Dr hemagglutinin. Dr blood group substance was found in tubular basement membrane and Bowman's capsule of the human kidney. Specific attachment of a Dr hemagglutinin-positive bacterial strain to the kidney substructures was inhibited by chloramphenicol.

Differential responses of B cells from the spleen and lymph node to TNP-Ficoll

Subcutaneous immunization with the thymus independent Ag, TNP-Ficoll, does not elicit plaque-forming cell response from the regional lymph node B cells even though a good response is obtained with the splenic B cells. Lymph node cells respond well to the thymus independent 1 Ag, TNP-Brucella abortus. Because TNP-Ficoll is a soluble Ag and may not be retained well in the lymph nodes, we emulsified it with Freund's adjuvant and injected it into foot pads. This did not result in any antibody response in the popliteal and inguinal lymph nodes though once again splenic B cells gave excellent responses. We find that the in vivo response to TNP-Ficoll can be induced in the lymph node if TNP-Ficoll is injected along with B. abortus in the foot pads of normal mice. This observation could not be repeated in the splenectomized mice implicating the role of the migration of APC or B cells from spleen to lymph nodes. Similar differential responses are obtained from lymph node and splenic B cells in the in vitro cultures. Lymph node cells respond to TNP-Ficoll with the addition of normal irradiated spleen cells but not with Sephadex G-10-passed spleen cells. This shows the absence of APC or lymphokines which stimulate B lymphocytes to respond to TNP-Ficoll in the lymph nodes. We found that IL-1 but not IL-2 or IL-4 was able to induce TNP-Ficoll response from the lymph node B cells.

Immune carrier properties of acid-treated Salmonella minnesota R595 bacteria. The immune response to TNP-bacterial conjugates in rabbits and mice

Salmonella minnesota R595 bacteria from which the core region of the lipopolysaccharide on the cell wall had previously been removed by mild acid treatment were trinitrophenylated. Differing amounts of these trinitrophenyl naked bacterial conjugates (TNP-NB), covering a range of epitope densities, were used for immunising mice and rabbits via the intraperitoneal or intravenous routes without adjuvants. It was found that such acid-treated, naked bacteria were effective carriers for the covalently linked hapten, TNP, with an optimum epitope density of 15 micrograms TNP/mg NB. Significant immune responses were obtained with dose levels as low as 50 ng TNP. The possible applications of acid-treated, naked bacteria as universal carriers having inherent adjuvant activity are discussed.

Inhibition of anti-hapten antibody plaque-forming cells by a chemically reactive hapten

The ability of the chemically reactive hapten 2-4-6-trinitrobenzene sulphonic acid (TNBSA) to inhibit anti-TNP IgM antibody plaque-forming cells (APFC) was investigated. TNBSA at a concentration of 1 mg (3 X 10(-3)M) to 0.3 mg (10(-3] completely inhibited IgM anti-TNP APFC after a 10-min incubation period at 37 degrees C. This inhibition was specific and did not alter the antifluorescein IgM antibody response. After a 24-h culture period in tissue culture medium without antigen, the non-dividing APFC remained inhibited, whereas the dividing APFC escaped this inhibition.

Ultrastructural localization of 2,4-dinitrophenyl groups in mouse epidermis following skin painting with 2,4-dinitrofluorobenzene and 2,4-dinitrothiocyanatebenzene: an immunoelectron microscopical study

The ultrastructural localization of 2,4-dinitrophenyl (DNP) groups in mouse epidermis after epicutaneous application of the contact sensitizer 2,4-dinitrofluorobenzene (DNFB) and the tolerogen 2,4-dinitrothiocyanatebenzene (DNTB) was investigated at varying times using immunoelectron microscopy with the protein A - gold technique. After application of DNFB, there was a homogenous cytoplasmic labeling of all epidermal cells. The intracellular localization of the DNP groups was not restricted to cytoplasmic organelles belonging to the endocytotic - lysosomal system. The numerous endocytotic organelles, Birbeck granules, and lysosomes of the Langerhans cells (LCs) typically observed after application of contact sensitizers also did not show an increased number of gold particles. Skin painting with DNTB resulted in a similar distribution and time-course of immunolabeling, but this compound did not induce cellular and the endocytotic activation of LCs as seen after DNFB application. These results demonstrate that contact sensitizers do not require specific cellular uptake and intracellular processing by the endocytotic - lysosomal compartment of the LCs before membrane presentation. However, a cellular and endocytotic activation of the LCs by haptens may be an important mechanism for T effector cell activation.

Murine anti-TNP antibodies positive for either lambda 1 or lambda 2 light chains express common idiotypic determinants

Although the lambda-bearing antibodies represent only 5% of the total mouse serum immunoglobulins, some antigens such as B1355 dextran (alpha (1-3)Dex), the 4-hydroxy-3-nitrophenyl acetyl (NP) and 2,4-dinitro or 2,4,6-trinitrophenyl (DNP/TNP) antigens can induce lambda-positive immune responses. In contrast to the lambda antibody response against alpha (1-3)Dex and NP antigens which is restricted to the lambda 1 isotype it was shown that the response to the DNP (or TNP) antigen uses lambda 1 and lambda 2 and lambda 3 isotypes. The idiotypy of the alpha (1-3)Dex and NP systems has been well characterized contrary to that of the lambda-positive anti-TNP/DNP response which has been poorly studied. In this paper, we describe two idiotopes (Id C19-3 and Id D11-2) shared by two BALB/c monoclonal anti-TNP antibodies (TNP5 and TNP9) which, respectively, use the lambda 1 and lambda 2 light chains. These idiotopes were independently expressed on other monoclonal anti-TNP/DNP antibodies and appear to require the use of a unique VH gene associated with a particular V lambda region. After TNP-Ficoll immunization, BALB/c mice recurrently express both idiotopes on lambda 1 and (lambda 2 + lambda 3) anti-TNP antibodies. In addition, all the mouse strains immunized against TNP-Ficoll give a lambda 1- and (lambda 2 + lambda 3)-positive immune response with the exception of SJL and SJA strains which present a deficit for the expression of lambda 1 light chain. The expression of Id C19-3 was restricted to the strains with the Igh-Va allotypic haplotype (including SJA) whereas the Id D11-2 was extensively expressed in the various strains.

Heteroclitic antibodies: differences in fine specificities between monoclonal antibodies directed against dinitrophenyl and trinitrophenyl haptens

The inhibition of binding of monoclonal antibodies by different haptens was studied using the 50% antibody binding assay. The binding of antidinitrophenyl and antitrinitrophenyl antibodies to dinitrophenylated or trinitrophenylated bovine serum albumin could be inhibited by monovalent dinitrophenyl or trinitrophenyl epsilon-aminocaproic acid. Some of the antibodies could be inhibited to a greater degree with the cross-reacting haptens than with the haptens homologous to the immunizing antigen, therefore these antibodies were heteroclitic.

In vitro generated human monoclonal trinitrophenyl-specific B cell lines. Evidence that human and murine anti-trinitrophenyl monoclonal antibodies cross-react with Escherichia coli beta-galactosidase

Stable human antigen-specific monoclonal B cell lines were established without prior in vivo immunization. This was accomplished by expanding the anti-trinitrophenyl (TNP) B cells in vitro with the antigen TNP-Brucella abortus and then immortalizing them with Epstein-Barr virus. Five anti-TNP clones were selected by sequential limiting dilution. All five anti-TNP clones secreted IgM kappa antibodies. When tested against a panel of self and environmental antigens, all five anti-TNP clones exhibited cross-reactivity with an Escherichia coli-derived beta-galactosidase. To determine whether this was a more general phenomenon, a panel of murine monoclonals were tested and found to bind to beta-galactosidase. It is therefore possible that human and murine anti-TNP beta cell responses reflect reactivity against an environmental antigen, namely an epitope present on E. coli-derived beta-galactosidase. This approach of expanding human antigen-specific B cells by antigen stimulation in vitro, with a T-independent hapten-carrier conjugate before Epstein-Barr virus transformation, may prove useful in the development of human monoclonals for therapeutic purposes.

Ir gene influence on DNP-specific B-memory-cell formation

It is well known that Ir genes control the antibody production. To investigate whether they also influence B-memory-cell generation, CBA mice (nonresponders) were primed with dinitrophenyl-poly-(L-tyr,L-glu)-poly-(D,L-ala)-poly-(L-lys)-DNP-TGAL conjugate. At the same time animals were injected with ovalbumin (OVA) to activate OVA-specific T helpers. Two to four weeks later animals were challenged with DNP-OVA conjugate and the number of IgG-producing B cells was determined. The data presented indicate that carrier-specific MHC-restricted T helpers are not required for B-memory-cell generation. It is concluded that the defect of IgG response to DNP-TGAL in CBA mice is caused by a block in the maturation of memory cells to antibody-producing cells.

A novel method to investigate the heterocliticity of antibodies

Monoclonal and anti-dinitrophenyl and anti-trinitrophenyl IgE antibodies were used to measure heterocliticity using competitive inhibition assays with homologous and heterologous haptens. The antibodies or antibody-containing ascites fluids were diluted to give 50% of the maximum binding to wells of antigen-coated microtiter plates. The % inhibition of binding of the antibody to the antigen by various concentrations of homologous and heterologous haptens at a standard dilution of antibody can then be compared. The advantages of this method of determination of heterocliticity are that it is fast, simple, quantitative and does not need radiolabeled reagents.

Both natural and induced murine anti-TNP antibodies possess anti-DNA activity

Sera of BALB/c mice immunized with either trinitrophenyl (TNP) coupled to bovine serum albumin (TNP/BSA) and Freund's adjuvant or TNP/BSA and TNP coupled to mouse serum albumin (TNP/MSA) without adjuvant were tested for antibody activity against a panel of antigens: TNP/BSA, DNA, actin, myosin, tubulin and transferrin. Anti-DNA antibody activity in the serum increased significantly in immunized mice; this activity followed the increase in the anti-TNP titres. Sera from MRL/lpr/lpr autoimmune mice were also tested for antibody activity against a panel of antigens. Again, it was found that the level of the anti-TNP antibodies followed the level of anti-DNA antibodies. Purified antibodies isolated from both immunized BALB/c and MRL/lpr/lpr mice on a dinitrophenol(DNP)-lysine immunoadsorbent shared antibody activity against both TNP and DNA. The results obtained suggest that a single region in the antibody binding site is responsible for both anti-DNA and anti-TNP activities, that TNP-like groups may represent a "public epitope" carried by various antigens and that antibodies obtained after experimental immunization and antibodies appearing in autoimmunopathological situations apparently possess similar specificities.

Trinitrobenzenesulphonic acid-induced unresponsiveness at the systemic level

To investigate the mechanism underlying B-cell tolerance, which is still discussed as being the consequence of (functional) clonal deletion or suppression, limiting dilution (LD) analysis of the frequencies of B cells as well as regulatory cells after tolerance induction with trinitrobenzenesulphonic acid (TNBS) was performed. It was shown that the frequency of functionally active hapten-specific B cells was decreased to less than 10% of the frequency in untreated BALB/c mice. After an immunogenic challenge, trinitrophenyl (TNP)-specific B cells of tolerized mice expanded, but did not reach the level of TNP-specific B cells in untreated mice. The expansion of TNP-specific B cells in TNBS-tolerized mice after challenge with TNP-horse red blood cells (HRBC) as observed in LD cultures was in contrast to the absence of anti-TNP plaque-forming cells (PFC) in freshly harvested spleen cells (SC) and the non-detectability of anti-TNP antibodies (AB). Hence, the functional deletion (= anergy) of B cells in vivo appears to be sustained by regulatory cells. Analysis of the regulatory compartment revealed that tolerance induction resulted in transient augmentation of TNP-specific helper T cells (TH), continuously elevated levels of suppressor T cells (TS), and a low level of contrasuppressor T cells (TCS). But, contrary to non-tolerized mice, TCS of tolerized mice were rather refractory to stimulation with TNP-HRBC. Hence, we would like to hypothesize that clonal anergy of B cells leads to inappropriate activation of TCS, whose nominal antigens are antibodies. This in turn sustains the persistence of high levels of TS, i.e. tolerance would be maintained by interruption of feedback activation of regulatory cells via effector cells/molecules.

Carrier-specific recognition for induction of secretory IgA anamnestic antibody responses

This study examined antigen-carrier specificity for the induction of secretory IgA antibodies in the saliva of rats. Conjugate antigens used as probes to examined the formation of SIgA antibodies included: DNP-BGG, DNP-OVA and DNP-Streptococcus mutans, as well as the unconjugated carriers BGG and OVA. The results showed that local immunization of rats with homologous hapten-carrier conjugates (i.e. DNP-BGG + DNP-BGG) resulted in secondary responses of salivary IgA and serum IgG and IgA antibodies to the hapten DNP. In contrast, heterologous conjugate (i.e. DNP-BGG + DNP-OVA) administration was unable to provide priming for anamnestic secretory or systemic responses. Priming of rats with unconjugated carrier was found to enhance the response to a local immunization with hapten-carrier antigen only in an homologous system. Also, significant carrier priming was most pronounced with serum IgG and IgA. While salivary IgA was increased somewhat following priming with unconjugated carrier, this was less than following two immunizations with the homologous hapten-carrier conjugate. These findings demonstrate carrier-specific reactions in the elicitation of secretory IgA antibodies and further support evidence of the importance of T-cell co-operation in the induction of secretory immune responses.

Ly-1 B helper cells in autoimmune "viable motheaten" mice

Previous work has demonstrated that Ly-1 B cells from normal C57BL/6J mice help the response of B cell subsets to the 4-hydroxy-3-nitrophenylacetyl hapten (NP). This regulatory cell population, called BH, preferentially helps the expression of plaque-forming B cells which express a predominant set of serologically related determinants collectively known as the NPb idiotype family. The specificity of BH cell activity in the NP system is a reflection of NPb idiotype-specific BH cell surface receptors. Thus, BH cells recognize autologous (i.e., idiotype) antigens. Given these observations and previous associations of increased Ly-1 B cell frequency in autoimmune mice, it was hypothesized that autoreactive Ly-1 BH cells may be present in high frequencies and in an activated state in autoimmune mice. To test this hypothesis the immunologic activity of BH cells in autoimmune viable motheaten (mev/mev) mice was studied. It was determined that splenic BH cells are approximately 10 times more frequent in viable motheaten than normal mice. The fact that BH cells from viable motheaten mice are activated was suggested by the presence of NPb idiotype-specific BH replacing helper activity in sera or B cell supernatants from these autoimmune mice. The soluble helper activities constitutively produced in mev/mev splenic B cell cultures and detected in mev/mev serum were resolved into two moieties, an NPb idiotype-specific immunoglobulin and a nonimmunoglobulin lymphokine(s) fraction. Purified mev/mev B cell-derived B cell maturation factor could substitute for the lymphokine moiety in the NPb idiotype helper cell assay. These results suggest that at least two signals, anti-idiotype immunoglobulin and a late-acting B cell maturation factor, are required for BH-dependent helper activity. The relationships of these results to current concepts of B cell activation mechanisms and the possible association of Ly-1 BH cells with autoimmunity are discussed.

Abnormal expression of surface immunoglobulin isotypes on antigen-binding B lymphocytes from mice tolerant to trinitrophenyl determinants

Temporary B-cell tolerance to the trinitrophenyl (TNP) hapten can be produced in BDF1 mice by intraperitoneal injection of trinitrobenzene sulfonic acid (TNBS). Antigen-binding cells (ABC) specific to TNP, measured as TNP donkey erythrocyte rosettes, are found in tolerant mice as well as in immune mice. We have studied the surface immunoglobulin isotype profile of these TNP-binding lymphocytes (TNP-ABC) in four groups of animals: nonimmune, immune, tolerant, and tolerant-challenged. Immune mice received intravenous TNP sheep erythrocytes (TNP-SRC), whereas tolerant-challenged mice received TNP-SRC and TNBS on Day 0. TNP-ABC from mice immunized with TNP-SRC exhibit increased expression of surface IgG and decreased expression of surface IgD, compared to the ABC from nonimmune mice. Tolerant mice have a higher proportion of ABC with surface IgG, and a lower proportion with surface IgD, than nonimmune mice. Tolerant-challenged mice have a lower proportion of ABC with surface IgG, and a higher proportion with surface IgD, than immune mice. Thus, B-cell tolerance in this model entails an attenuation of the surface immunoglobulin isotype switch (loss of IgD and gain of IgG) on ABC seen in the normal immune response. For most TNP-ABC, tolerogen exposure prevents the switch in surface isotypes normally induced by exposure to TNP antigen; i.e., the tolerance lesion precedes the surface isotype switch. However, a minority of the TNP-ABC appear to switch surface isotypes in response to the tolerogen itself.

Control of the immune response to contact sensitizing chemicals by cutaneous antigen-presenting cells

The fate of 2,4-dinitrochlorobenzene, a potent contact sensitizing chemical, and 2,4-dichloronitrobenzene, a non-sensitizer, was compared following their application to the skin of BALB/c mice. Although both chemicals were able to bind to protein in vitro and were capable of being absorbed across mouse skin in vivo, only 2,4-dinitrochlorobenzene was able to bind to cells in the skin and to induce the movement of these cells from the epidermis into the dermis and ultimately into the draining lymph nodes. The sensitization potential of a chemical may therefore be dependent on its ability to associate with and stimulate the efflux of cutaneous antigen-presenting cells.

Idiotypic multireactivity of 'natural' antibodies. 'Natural' anti-idiotypes also inhibit helper cells with cross-reactive clonotypes

One hundred and twenty IgM-secreting hybridomas derived from unmanipulated 6-day-old BALB/c mice were screened for reactivity with the prototype idiotypic and anti-idiotypic monoclonal antibodies, defining three well established systems, namely TEPC 15:10/13-15, J558:CD3.2, and MOPC 460:F 6(51). Up to 25% of all IgM antibodies reacted with at least one of the six specific ligands, half of the latter being 'monospecific', the others reacting with two or more antibodies. A detailed analysis of the four most multi-reactive clones showed individually specific patterns of reactivity and revealed reactions of the same IgM molecule in idiotypic systems previously studied independently. Furthermore, when tested for functional interactions with syngeneic helper T cells expressing MOPC 460-like clonotypes, one of these antibodies was found to inhibit effector helper activity. The results show the existence of 'natural antibodies' with idiotypic reactivities related to recurrent clonotypes in the strain. They may be either 'specific' or 'multireactive', and might connect idiotypes on T and B cells and on antigenic systems so far studied independently.

Two BALB/c anti-arsonate idiotype families: two heavy chain variable regions (Vh) shared with anti-DNP antibodies are used by one family while a Vh similar to anti-GAT antibodies is used by the other

Amino terminal amino acid sequences were obtained for both the heavy (H) and light (L) chains of seven BALB/c anti-arsonate (Ar) monoclonal antibodies representing the 5AF6 and 3C6 idiotype (id) families described in this strain. 5AF6 family H chains showed strong homology to the germ-line gene sequence for the A strain 36-60 family. However, four to five identical H chain sequence differences for two of these antibodies (5AF6 and 95B5), as well as two previously reported related sequences (92D5, 94B10), suggested they were encoded by a different Vh. The 36-60 family Vh genes have been shown to be identical to the Vh gene of the anti-DNP binding myeloma M460 [Dzierzak et al., J. Immun. 136, 1864-1870 (1986)]. H chains amino acid sequences derived from an id-460+ anti-DNP hybridoma and a germ-line gene differing from the 30-60-like Vh sequence [Dzierzak et al., J. Immun. 136, 1864-1870 (1986)] were found to be virtually identical to the 95B5 and 5AF6 Vh sequences. This suggests that the same two related H chains making up two subsets of the 5AF6 anti-Ar id family are also both used in two subsets of the id-460 anti-DNP response. 5AF6 family L chains were highly homologous to the other Vk2 L chains of the 36-60 family. 3C6 family H chains can be placed in the Vh l group, are unrelated to the described anti-Ar H chain families, and have been placed in a new anti-Ar Vh family, Ars-E. The 3C6 H is similar, however, to a Vh used by a BALB/c anti-GAT idiotype family of antibodies. 3C6 L chains were of the murine kappa chain group, Vk8 and most resembled an L chain from an A strain monoclonal anti-Ar having no defined idiotype.

Rat C3 conversion by rat anti-2,4,dinitrophenyl (DNP) hapten IgA immune precipitates

Monomeric (m-) and polymeric (p-) anti-DNP monoclonal (MC) rat IgA antibodies (Ab) were tested for precipitation with DNP-bovine serum albumin (DNP-BSA) and C3 conversion in rat serum, with rat MC anti-DNP IgG2b used as reference. At equivalence, p-IgA rapidly precipitated DNP-BSA, with little antigen (Ag) left in the supernatant. In contrast, m-IgA at five-fold higher concentration precipitated Ag very slowly, with less than 50% of Ag precipitated at equivalence. The Ag/Ab weight ratio at equivalence was 0.13 for both m- and p-IgA, but the molar ratio was 0.3 for m-IgA and close to 1.0 for p-IgA, suggesting a higher avidity of p-IgA. Rat C3 conversion by rat IgA immune precipitates (IP) was about 20% with m-IgA and 40% with p-IgA. EGTA did not significantly affect these figures. Therefore, rat MC IgA IP activated the rat alternative C pathway. Neither rat nor mouse IgA anti-DNP IP activated C3 in normal human serum.

Immunomodulation with liposomes: the immune response elicited by liposomes with entrapped dichloromethylene-diphosphonate and surface-associated antigen or hapten

Macrophages in the murine spleen were eliminated by the intravenous administration of dichloromethylene-diphosphonate (DMDP) encapsulated in liposomes. The immune response against an antigen (bovine serum albumin, BSA) or hapten (dinitrophenyl, DNP) associated with the surface of the DMDP liposomes was studied. Significant effects of macrophage elimination on the primary (IgM), but not on the secondary (IgG), anti-BSA response were found. Dramatic effects on the response against liposome-associated DNP were observed in macrophage-depleted mice. The number of anti-DNP antibody-forming cells in the spleen decreased from 300 to 28 per section, and anti-DNP serum titres dropped to 12% of their normal values. Since a similar phenomenon was observed for TNP-Ficoll, a thymus-independent type-2 antigen (and not for thymus-dependent or thymus-independent type-1 antigens), we suggest that this response should be classified as thymus-independent type-2 on grounds of its in vivo behaviour. We conclude that adjuvant activity (and memory formation) of liposomes with antigen exposed on their surface occurs irrespective of the presence or absence of splenic macrophages, and that DMDP liposomes could be useful in drug targeting with antigenic liposomes.