Allergic reactions to colloid fluids in anesthesia.

Allergic reactions in anesthesia are a rare event, however, might be life threatening when occurred. Clinical manifestations may not be indicative at first, and difficult to differentiate from different situations during operation and anesthesia. Colloids represent a group of fluids often used during perioperative period that, among other adverse reactions, have an allergic potential. Albumin is a natural colloid that has the lowest incidence of these reactions. However, it is found as an additional substance in other blood products, and, therefore, has to be taken into consideration if anaphylaxis occurs. Dextrans cause the most severe reactions due to dextran reactive antibodies. Pretreatment with Dextran 1 may inhibit the reaction. Gelatins have the highest incidence of anaphylaxis among colloids. Patients with history of allergy to some food, vaccines, cosmetics containing gelatin are at greater perioperative risk for anaphylaxis. Not to forget, gelatins are also a part of topical haemostatic agents used in surgery. Testing for colloid allergies is limited due to their pathophysiologic mechanism, so the clinical assessment is usually essential. Treatment of anaphylaxis caused by colloids is the same as for any other cause. This is a review of the most common colloids and their association with allergic reactions in everyday practice.

Variability of Complement Response toward Preclinical and Clinical Nanocarriers in the General Population.

Opsonization (coating) of nanoparticles with complement C3 component is an important mechanism that triggers immune clearance and downstream anaphylactic and proinflammatory responses. The variability of complement C3 binding to nanoparticles in the general population has not been studied. We examined complement C3 binding to dextran superparamagnetic iron oxide nanoparticles (superparamagnetic iron oxide nanoworms, SPIO NWs, 58 and 110 nm) and clinically approved nanoparticles (carboxymethyl dextran iron oxide ferumoxytol (Feraheme, 28 nm), highly PEGylated liposomal doxorubicin (LipoDox, 88 nm), and minimally PEGylated liposomal irinotecan (Onivyde, 120 nm)) in sera from healthy human individuals. SPIO NWs had the highest variation in C3 binding (n = 47) between subjects, with a 15-30 fold range in levels of C3. LipoDox (n = 12) and Feraheme (n = 18) had the lowest levels of variation between subjects (an approximately 1.5-fold range), whereas Onivyde (n = 18) had intermediate between-subject variation (2-fold range). There was no statistical difference between males and females and no correlation with age. There was a significant correlation in complement response between small and large SPIO NWs, which are similar structurally and chemically, but the correlations between SPIO NWs and other types of nanoparticles, and between LipoDox and Onivyde, were not significant. The calculated average number of C3 molecules bound per nanoparticle correlated with the hydrodynamic diameter but was decreased in LipoDox, likely due to the PEG coating. The conclusions of this study are (1) all nanoparticles show variability of C3 opsonization in the general population; (2) an individual's response toward one nanoparticle cannot be reliably predicted based on another nanoparticle; and (3) the average number of C3 molecules per nanoparticle depends on size and surface coating. These results provide new strategies to improve nanomedicine safety.

Immunoadjuvant potential of cross-linked dextran microspheres mixed with chitosan nanospheres encapsulated with tetanus toxoid.

CONTEXT: Nasal mucosa is a desirable route for mucosal vaccine delivery. Mucosal co-administration of chitosan nanoparticles with absorption enhancers such as cross-linked dextran microspheres (CDM, Sephadex®) is a promising antigen delivery system. OBJECTIVE: In the current study, the chitosan nanospheres loaded with tetanus toxoid (CHT:TT NPs) was prepared and characterized. The immune responses against tetanus toxoid after nasal administration of CHT:TT NPs alone or mixed with CDM were also determined. MATERIALS AND METHODS: Chitosan nanospheres were prepared by ionic gelation method. Particle size, releasing profile and antigen stability were evaluated by dynamic light scattering, diffusion chamber and SDS-PAGE methods, respectively. Rabbits were nasally immunized with different formulations loaded with 40 Lf TT. After three times immunizations with 2 weeks intervals, sera IgG titres and nasal lavage sIgA titres were determined. RESULTS: Mean size of CHT NPs and CHT:TT NPs were 205 ± 42 nm and 432 ± 85 nm, respectively. The release profile showed that 42.4 ± 10.5% of TT was released after 30 min and reached to a steady state after 1.5 h. Stability of encapsulated TT in nanospheres was confirmed by SDS-PAGE. The antibody titres showed that CHT:TT NPs-induced antibody titres were higher than TT solution. CHT NPs mixed with CDM induced the systemic IgG and nasal lavage sIgA titres higher than intranasal administration of TT solution (p < 0.001). DISCUSSION AND CONCLUSION: As the results indicated, these CHT:TT NPs when co-administered with CDM were able to induce more immune responses and have the potential to be used in mucosal immunization.

The (1->6)-ß-glucan moiety represents a cross-reactive epitope of infection-induced malignancy surveillance.

Exposure to pathogen-associated molecular patterns (PAMPs) by vaccination or infection is known to have beneficial effects on neoplastic diseases, although the underlying molecular mechanisms are so far unclear. In this article, we report that Abs against (1→6)-ß-d-glucan, a typical microbial PAMP and a major target for high titer circulating natural Abs in healthy human subjects, cross-recognize a novel tumor-associated carbohydrate Ag on cancer cells. The (1→6)-ß-glucan cross-reactive moiety is immunologically dominant in tumor cells, as C57BL/6 mice harboring EL-4 solid tumors produced anti-(1→6)-ß-glucan Abs and the titer of which significantly correlated with enhanced survival and smaller tumor burden. Moreover, the (1→6)-ß-glucan-specific Abs exhibited potent tumoricidal activities in vitro. C57BL/6 mice immunized with Candida albicans produced protective immunity against inoculated EL-4 tumors, which was attributed to the formation of (1→6)-ß-glucan-specific Abs. Importantly, (1→6)-ß-glucan-specific Abs significantly prolonged the survival and reduced the tumor size in mice inoculated with EL-4 tumors. Our results demonstrate that the (1→6)-ß-glucan cross-reactive moiety represents a focal point between infection immunity and cancer surveillance, and natural Abs against this epitope may contribute to the first-line antitumor surveillance in humans. Our data also provide important explanation for the long-observed relationship between feverish infection and concurrent remission from cancer.

Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA).

Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR), the purpose of this study was to explore the potential of various intravenous iron preparations, non-dextran-based or dextran/dextran-based, to induce these reactions. An IgG-isotype mouse monoclonal anti-dextran antibody (5E7H3) and an enzyme-linked immunosorbent assay (ELISA) were developed to investigate the dextran antigenicity of low molecular weight iron dextran, ferumoxytol, iron isomaltoside 1000, ferric gluconate, iron sucrose and ferric carboxymaltose, as well as isomaltoside 1000, the isolated carbohydrate component of iron isomaltoside 1000. Low molecular weight iron dextran, as well as dextran-based ferumoxytol and iron isomaltoside 1000, reacted with 5E7H3, whereas ferric carboxymaltose, iron sucrose, sodium ferric gluconate, and isolated isomaltoside 1000 did not. Consistent results were obtained with reverse single radial immunodiffusion assay. The results strongly support the hypothesis that, while the carbohydrate alone (isomaltoside 1000) does not form immune complexes with anti-dextran antibodies, iron isomaltoside 1000 complex reacts with anti-dextran antibodies by forming multivalent immune complexes. Moreover, non-dextran based preparations, such as iron sucrose and ferric carboxymaltose, do not react with anti-dextran antibodies. This assay allows to assess the theoretical possibility of a substance to induce antibody-mediated DIARs. Nevertheless, as this is only one possible mechanism that may cause a hypersensitivity reaction, a broader set of assays will be required to get an understanding of the mechanisms that may lead to intravenous iron-induced hypersensitivity reactions.

A single bout of dynamic exercise by healthy adults enhances the generation of monocyte-derived-dendritic cells.

The ex vivo generation of monocyte-derived-dendritic cells (mo-DCs) has facilitated the use of DCs in immunotherapy research. However, low blood monocyte numbers frequently limit the manufacture of sufficient numbers of mo-DCs for subsequent experimental and clinical procedures. Because exercise mobilizes monocytes to the blood, we tested if acute dynamic exercise by healthy adults would augment the generation of mo-DCs without compromising their differentiation or function. We compared mo-DC generation from before- and after-exercise blood over 8-days of culture. Function was assessed by FITC-dextran uptake and the stimulation of autologous cytomegalovirus (pp65)-specific-T-cells. Supporting the hypothesis, we found a near fourfold increase in number of mo-DCs generated after-exercise. Furthermore, relative FITC-dextran uptake, differentiation rate, and stimulation of pp65-specific-T-cells did not differ between before- and after-exercise mo-DCs. We conclude that exercise enhances the ex vivo generation of mo-DCs without compromising their function, and so may overcome some limitations associated with manufacturing these cells for immunotherapy.

Preparation and Characteristic of Dextran-BSA Antibody and Establishment of its ELISA Immunoassay.

The enzyme-linked immunosorbent assay (ELISA) is a potential tool for the determination of dextran. In this study, dextran neoglycoprotein antigens were prepared by Reductive Amination method, and were confirmed by SDS-PAGE and free amino detection. The impact factors such as different oxidation degree of dextran, the conjugate reaction time to BSA were investigated. The best preparation conditions were obtained (n(dextran)/n(oxidant) of NaIO4 = 1/120, the reaction time of 24 h), and the antigen with best combination with standard was obtained. The antigens interacted with standard antibody and were evaluated through ELISA. The immunogen was immunized with white rabbits to obtained antibody, respectively. A general and broad class-specific ELISA immunoassay was developed for dextran detection according to ELISA theory. The optimized conditions of assay used coating antigen at 10 µg/mL, reaction time of antibody and rabbit-anti-bovine IgG in 45 min, blocking reagents with 5% calf serum. The developed ELISA detection method with good linear and accuracy was put to use for quantitative analysis of dextran T40 in commercial sugarpractical for detection of dextran.

The potential of dextran-based glycoconjugates for development of Helicobacter pylori vaccine.

We have recently demonstrated that synthetic glycoconjugates based on delipidated lipopolysaccharide (LPS) of Helicobacter pylori and containing an α(1-6)-glucan chain induced broadly cross-reactive functional antibodies in immunized animals. To investigate the candidacy of α(1-6)-glucan as an alternative vaccine strategy we prepared glycoconjugates based on dextrans produced by lactic acid bacteria Leuconostoc mesenteroides B512F and consisting of linear α(1-6)-glucan chains with limited branching. Three dextrans with averaged molecular masses of 5,000 Da, 3,500 Da and 1,500 Da, respectively, were modified with a diamino group-containing linker and conjugated to a carrier protein, tetanus toxoid (TT) or diphtheria toxoid (DT), and their immunological properties investigated. The conjugates were immunogenic in both rabbits and mice and induced specific IgG responses against α(1-6)-glucan-expressing H. pylori LPS. Studies performed with post-immune sera of mice and rabbits immunized with dextran-based conjugates demonstrated cross-reactivity with LPS from typeable and non-typeable strains of H. pylori and selected mutants. The post-immune sera from rabbits that received the conjugates exhibited functional activity against α(1-6)-glucan-positive strains of H. pylori. These data provide evidence that dextran-based conjugates may offer a simplified approach to the development of carbohydrate-based vaccines against H. pylori.

Long-term maintenance of polysaccharide-specific antibodies by IgM-secreting cells.

Many bacteria-associated polysaccharides induce long-lived Ab responses that protect against pathogenic microorganisms. The maintenance of polysaccharide-specific Ab titers may be due to long-lived plasma cells or ongoing Ag-driven B cell activation due to polysaccharide persistence. BALB/c and V(H)J558.3 transgenic mice respond to α1→3-dextran (DEX) by generating a peak anti-DEX response at 7 d, followed by maintenance of serum Ab levels for up to 150 d. Analysis of the cellular response to DEX identified a population of short-lived, cyclophosphamide-sensitive DEX-specific plasmablasts in the spleen, and a quiescent, cyclophosphamide-resistant DEX-specific Ab-secreting population in the bone marrow. BrdU pulse-chase experiments demonstrated the longevity of the DEX-specific Ab-secreting population in the bone marrow. Splenic DEX-specific plasmablasts were located in the red pulp with persisting DEX-associated CD11c(+) dendritic cells 90 d after immunization, whereas DEX was not detected in the bone marrow after 28 d. Selective depletion of short-lived DEX-specific plasmablasts and memory B1b B cells using cyclophosphamide and anti-CD20 treatment had a minimal impact on the maintenance of serum anti-DEX Abs. Collectively, these findings demonstrate that the maintenance of serum polysaccharide-specific Abs is the result of continuous Ag-driven formation of short-lived plasmablasts in the spleen and a quiescent population of Ab-secreting cells maintained in the bone marrow for a long duration.

Targeting the C-type lectins-mediated host-pathogen interactions with dextran.

Dextran, the α-1,6-linked glucose polymer widely used in biology and medicine, promises new applications. Linear dextran applied as a blood plasma substitute demonstrates a high rate of biocompatibility. Dextran is present in foods, drugs, and vaccines and in most cases is applied as a biologically inert substance. In this review we analyze dextran's cellular uptake principles, receptor specificity and, therefore, its ability to interfere with pathogen-lectin interactions: a promising basis for new antimicrobial strategies. Dextran-binding receptors in humans include the DC-SIGN (dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin) family receptors: DC-SIGN (CD209) and L-SIGN (the liver and lymphatic endothelium homologue of DC-SIGN), the mannose receptor (CD206), and langerin. These receptors take part in the uptake of pathogens by dendritic cells and macrophages and may also participate in the modulation of immune responses, mostly shown to be beneficial for pathogens per se rather than host(s). It is logical to predict that owing to receptor-specific interactions, dextran or its derivatives can interfere with these immune responses and improve infection outcome. Recent data support this hypothesis. We consider dextran a promising molecule for the development of lectin-glycan interaction-blocking molecules (such as DC-SIGN inhibitors) that could be applied in the treatment of diseases including tuberculosis, influenza, hepatitis B and C, human immunodeficiency virus infection and AIDS, etc. Dextran derivatives indeed change the pathology of infections dependent on DC-SIGN and mannose receptors. Complete knowledge of specific dextran-lectin interactions may also be important for development of future dextran applications in biological research and medicine.

Co-transfection gene delivery of dendritic cells induced effective lymph node targeting and anti-tumor vaccination.

PURPOSE: Successful genetically engineered Dendritic Cell (DC) can enhance DC's antigen presentation and lymph node migration. The present study aims to genetically engineer a DC using an efficient non-viral gene delivery vector to induce a highly efficient antigen presentation and lymph node targeting in vivo. METHODS: Spermine-dextran (SD), a cationic polysaccharide vector, was used to prepare a gene delivery system for DC engineering. Transfection efficiency, nuclear trafficking, and safety of the SD/DNA complex were evaluated. A vaccine prepared by engineering DC with SD/gp100, a plasmid encoding melanoma-associated antigen, was injected subcutaneously into mice to evaluate the tumor suppression. The migration of the engineered DCs was also evaluated in vitro and in vivo. RESULTS: SD/DNA complex has a better transfection behavior in vitro than commercially purchased reagents. The DC vaccine co-transfected with plasmid coding CCR7, a chemokine receptor essential for DC migration, and plasmid coding gp100 displayed superior tumor suppression than that with plasmid coding gp100 alone. Migration assay demonstrated that DC transfected with SD/CCR7 can promote DC migration capacity. CONCLUSIONS: The study is the first to report the application of nonviral vector SD to co-transfect DC with gp100 and CCR7-coding plasmid to induce both the capacity of antigen presentation and lymph node targeting.

Limiting CDR-H3 diversity abrogates the antibody response to the bacterial polysaccharide α 1→3 dextran.

Anti-polysaccharide Ab responses in mice are often oligoclonal, and the mechanisms involved in Ag-specific clone production and selection remain poorly understood. We evaluated the relative contribution of D(H) germline content versus N nucleotide addition in a classic oligoclonal, T-independent Ab response (α 1→3 dextran [DEX]) by challenging adult TdT-sufficient (TdT(+/+)) and TdT-deficient (TdT(-/-)) gene-targeted mice, limited to the use of a single D(H) gene segment (D-limited mice), with Enterobacter cloacae. D-limited mice achieved anti-DEX-specific levels of Abs that were broadly comparable to those of wild-type (WT) BALB/c mice. Sequence analysis of the third CDR of the H chain intervals obtained by PCR amplification of V(H) domain DNA from DEX-specific plasmablasts revealed the near universal presence of an aspartic acid residue (D99) at the V-D junction, irrespective of the composition of the D(H) locus. Although WT mice were able to use germline D(H) (DQ52, DSP, or DST) gene segment sequence, TdT activity, or both to produce D99, all three D-limited mouse strains relied exclusively on N addition. Additionally, in the absence of TdT, D-limited mice failed to produce a DEX response. Coupled with previous studies demonstrating a reduced response to DEX in TdT(-/-) mice with a WT D(H) locus, we concluded that in the case of the anti-DEX repertoire, which uses a short third CDR of the H chain, the anti-DEX response relies more intensely on sequences created by postnatal N nucleotide addition than on the germline sequence of the D(H).

Terminal deoxynucleotidyl transferase is required for an optimal response to the polysaccharide α-1,3 dextran.

An understanding of Ab responses to polysaccharides associated with pathogenic microorganisms is of importance for improving vaccine design, especially in neonates that respond poorly to these types of Ags. In this study, we have investigated the role of the lymphoid-specific enzyme TdT in generating B cell clones responsive to alpha-1,3 dextran (DEX). TdT is a DNA polymerase that plays a major role in generating diversity of lymphocyte AgRs during V(D)J recombination. In this study, we show that the DEX-specific Ab response is lower, and the dominant DEX-specific J558 idiotype (Id) is not detected in TdT(-/-) mice when compared with wild-type (WT) BALB/c mice. Nucleotide sequencing of H chain CDR3s of DEX-specific plasmablasts, sorted postimmunization, showed that TdT(-/-) mice generate a lower frequency of the predominant adult molecularly determined clone J558. Complementation of TdT expression in TdT(-/-) mice by early forced expression of the short splice variant of TdT-restored WT proportions of J558 Id+ clones and also abrogated the development of the minor M104E Id+ clones. J558 Id V(D)J rearrangements are detected as early as 7 d after birth in IgM-negative B cell precursors in the liver and spleen of WT and TdT-transgenic mice but not in TdT(-/-) mice. These data show that TdT is essential for the generation of the predominant higher-affinity DEX-responsive J558 clone.

Curvature of synthetic and natural surfaces is an important target feature in classical pathway complement activation.

The binding of Abs to microbial surfaces followed by complement activation constitutes an important line of defense against infections. In this study, we have investigated the relationship between complement activation and the binding of human IgM Abs to surfaces with different curvatures. IgM Abs to dextran were shown to activate complement potently on dextran-coated particles having a diameter around 250 nm, whereas larger (600 nm) particles were less potent activators. This selectivity regarding particle dimension was also found for complement activation by colloidal substances of microbial origin. Peptidoglycan (PGN) is the major chemical component in the cell wall of Gram-positive bacteria. Fragments of purified PGN with sizes of approximately 100 nm promoted complement activation effectively through the classical pathway. By contrast, larger or smaller fragments of PGN did not activate complement strongly. A careful analysis of PGN fragments released during planctonic growth of Staphylococcus aureus showed that these include curvatures that would permit strong IgM-mediated complement activation, whereas the curvature of intact cells would be less effective for such activation. Consistently, we found that the suspended PGN fragments were strong activators of complement through the classical pathway. We suggest that these fragments act as decoy targets for complement activation, providing protection for S. aureus against the host immune response to infection.

Absence of N addition facilitates B cell development, but impairs immune responses.

The programmed, stepwise acquisition of immunocompetence that marks the development of the fetal immune response proceeds during a period when both T cell receptor and immunoglobulin (Ig) repertoires exhibit reduced junctional diversity due to physiologic terminal deoxynucleotidyl transferase (TdT) insufficiency. To test the effect of N addition on humoral responses, we transplanted bone marrow from TdT-deficient (TdT(-/-)) and wild-type (TdT(+/+)) BALB/c mice into recombination activation gene 1-deficient BALB/c hosts. Mice transplanted with TdT(-/-) cells exhibited diminished humoral responses to the T-independent antigens α-1-dextran and (2,4,6-trinitrophenyl) hapten conjugated to AminoEthylCarboxymethyl-FICOLL, to the T-dependent antigens NP(19)CGG and hen egg lysozyme, and to Enterobacter cloacae, a commensal bacteria that can become an opportunistic pathogen in immature and immunocompromised hosts. An exception to this pattern of reduction was the T-independent anti-phosphorylcholine response to Streptococcus pneumoniae, which is normally dominated by the N-deficient T15 idiotype. Most of the humoral immune responses in the recipients of TdT(-/-) bone marrow were impaired, yet population of the blood with B and T cells occurred more rapidly. To further test the effect of N-deficiency on B cell and T cell population growth, transplanted TdT-sufficient and -deficient BALB/c IgM(a) and congenic TdT-sufficient CB17 IgM(b) bone marrow were placed in competition. TdT(-/-) cells demonstrated an advantage in populating the bone marrow, the spleen, and the peritoneal cavity. TdT deficiency, which characterizes fetal lymphocytes, thus appears to facilitate filling both central and peripheral lymphoid compartments, but at the cost of altered responses to a broad set of antigens.

CD16/32-specific biotinylated 2.4G2 single-chain Fv complexed with avidin-FITC enhances FITC-specific humoral immune response in vivo in a CD16-dependent manner.

Fcgamma receptors (FcgammaRs) play an essential role in the regulation of immune response due to their ability to bind immune complexes. Activating FcgammaRs may facilitate antigen presentation and dendritic-cell maturation, while in the late phase of the immune response, the inhibitory FcgammaRIIb may down-regulate B-cell activation upon cross-linking with activating receptors. In this study, we investigated the in vivo role of FcgammaRs on the modulation of humoral immune response. In order to get well-defined immune complexes that can bind to both the activating and the inhibitory FcgammaRs, we designed a mono-biotinylated single-chain fragment variable construct from the rat anti-mouse CD16/32 clone 2.4G2, linked to avidin-FITC, and tested its effect on the FITC-hapten-specific T-independent type 2 (TI-2) and T-dependent (TD) immune response. When injected intravenously in mice, the complex bound to a small portion of B220+, CD11b(high) and CD11c(high) cells and was localized in the spleen on marginal zone macrophages 15 min after treatment. When applied as a booster following primary immunization with TI-2 (FITC-dextran) or TD (FITC-keyhole limpet haemocyanin) antigens, the complex elevated the number of hapten-specific IgM/IgG-producing B cells. This effect was diminished in CD16KO mice, suggesting that the activating-type FcgammaRIII might be a key mediator of this mechanism.

Generation of B cell memory to the bacterial polysaccharide alpha-1,3 dextran.

B1b B cells generate a novel form of memory and provide Ab mediated-protection to persisting bacterial pathogens. To understand how B1b B cells establish memory to polysaccharide Ags, we studied an oligoclonal B cell response to alpha-1,3 dextran (DEX) expressed on Enterobacter cloacae. B cells specific for DEX enrich in the marginal zone (MZ) and B1b B cell populations. After E. cloacae immunization, MZ B cells were responsible for the generation of initial peak DEX-specific Ab titers, whereas, DEX-specific B1b B cells expanded and played an important role in boosted production of DEX-specific Ab titers upon E. cloacae rechallenge. Cell transfer experiments demonstrate that B1b B cells possess the capacity for both robust proliferation and plasma cell differentiation, thus distinguishing themselves from MZ B cells, which uniformly commit to plasma cell differentiation. These results define B1b B cells as the principal reservoir for memory to bacterial-associated polysaccharide Ags.

A comparison between isolated blood dendritic cells and monocyte-derived dendritic cells in pigs.

Various dendritic cell (DC) populations exist that differ in phenotype and ability to present antigen to T cells. For example, plasmacytoid DCs (pDCs) are less potent T cell activators compared with conventional DCs (cDCs). Here, we compared porcine blood DCs (BDCs), containing pDCs and cDCs, and monocyte-derived DCs (MoDC), consisting of cDCs, in their phenotype, ability to uptake antigen, activation and maturation and their ability to present antigen to autologous T cells. Pigs represent an important animal model, whose immune system in many respects closely resembles that of humans. For example, the distribution of Toll-like receptors is similar to that of humans, in contrast to that of mice. Here we demonstrate that both populations endocytose foreign material. Following lipopolysaccharide stimulation, CD80/86 and chemokine receptor (CCR)7 expression was increased in both populations as was the expression of the chemokine ligands (CCL)-2, CCL-4, CCL-20 and CXCL-2. Although basal and post-stimulation protein concentrations of interleukins 6 and 8 and tumour necrosis factor-alpha were higher in MoDCs, protein concentrations showed a higher fold increase in BDCs. Antigen-specific proliferation of autologous T cells was induced by MoDCs and BDCs. Interestingly, while MoDCs induced stronger proliferation in naive T cells, no difference in proliferation was observed when primed T cells were studied. These results demonstrate that isolated porcine BDCs are highly responsive to stimulation with lipopolysaccharide and are functionally able to drive primed T-cell proliferation to the same extent as MoDCs.

Immunochemical specificity of the combining site of murine myeloma protein CAL20 TEPC1035 reactive with dextrans.

The immunochemical specificity of the combining sites of murine myeloma protein CAL20 TEPC1035 was studied by quantitative precipitin and precipitin inhibition assays. Myeloma protein CAL20 TEPC1035 precipitated with only three dextrans, B1355S4, B1498S, and B1501S, with high proportions of alpha(1 leads to 3) linkages, but not with any other dextrans, glycogen, and pullulan. Inhibition tests with various sugars show that the combining site of myeloma protein CAL20 TEPC1035 is most complementary to panose, a trisaccharide DGlc alpha(1 leads to 6)DGlc alpha(1 leads to 4)DGlc. Panose was 3.3 times more potent than a tetrasaccharide DGlc alpha(1 leads to 6)DGlc alpha(1 leads to 4)DGlc alpha(1 leads to 4)DGlc and 8, 23, 42, > 42 times more active than maltose, nigerose, isomaltose, and kojibiose, respectively. These findings were paralleled by their binding properties as determined by affinity electrophoresis. The association constants (Ka) of these three dextrans to myeloma protein CAL20 TEPC1035 ranged from 3.8 X 10(3) ml/g to 5.02 X 10(3) ml/g. The association constant of inhibitor (Kia) of panose was 8.19 X 10(3) M-1. Myeloma protein CAL20 TEPC1035 is an antidextran with specificity different from those of other murine myeloma antidextrans and from human antidextrans reported previously and its combining site size is at least as large as a trisaccharide. The binding constant of methyl alpha-D-glucoside (7.2 X 10(2)) was 73% of that of panose and comparable to that of myeloma protein W3129 (9.4 X 10(2)) with a cavity-type site and 600 times lower (1.6 X 10(0)) for QUPC52 with a groove type site, indicating that the terminal nonreducing residue is held in a cavity. Inhibition data with various alpha(1 leads to 4)-linked oligosaccharides also indicate that the internal portions of these inhibitors may react directly with a portion of the combining site. These findings suggest that myeloma antidextran CAL20 TEPC1035 has a partial cavity-type combining site in which the terminal nonreducing dGlc alpha(1 leads to 6) moiety is held in a cavity with the other two sugars forming a groove. However, oligosaccharides with one or more alternating [leads to 3DGlc alpha(1 leads to 6)DGlc alpha(1 leads to 3)DGlcl leads to] units with and without terminal nonreducing DGlc alpha(1 leads to 6) or DGLc alpha(1 leads to 3) side chains remain to be tested to determine whether structures known to be present in the three dextrans which precipitate CAL20 TEPC1035 may not prove to be more active than panose.

Shared antigenic determinants by mitogen receptors and antibody molecules to the same thymus-independent antigen.

The antibody response to dextran B1355 is thymus independent, and in high responder mice, over 90% of the antibodies carry the idiotype of an alpha-1,3 binding myeloma protein (J558). The present experiments demonstrate: (a) dextran B1355 is a B-cell mitogen both in a strain which carries the J558 idiotype on antibodies and in a low-responder strain which does not express that idiotype on antibodies to dextran; (b) anti-idiotypic antibodies to J558 recognize a dextran-specific surface receptor on 10--15% of all splenic B cells in those two strains as well as in all strains so far tested; (c) as shown by inhibition experiments such surface receptors cross-react with J558, and (d) anti-idiotypic antibodies are mitogenic for spleen cells of both strains resulting in B-cell proliferation and maturation to polyclonal antibody secretion.