scholarly journals Enhanced T cell responses to antigenic peptides targeted to B cell surface Ig, Ia, or class I molecules.

1988 ◽  
Vol 168 (1) ◽  
pp. 171-180 ◽  
Author(s):  
L A Casten ◽  
P Kaumaya ◽  
S K Pierce

The helper T cell recognition of soluble globular protein antigens requires that the proteins be processed by an APC, releasing a peptide that is transported to and held on the APC surface where it is recognized by the specific T cell in conjunction with Ia. When cellular processing functions are blocked, APC lose their ability to present native antigens while retaining the capacity to activate T cells when provided with a cognate peptide fragment that contains the T cell antigenic determinant. In this report, we show that a peptide fragment of the soluble globular protein antigen tobacco hornworm moth cytochrome c, residues 92-103 containing an additional NH2-terminal cysteine residue (THMcCys92-103), is effectively presented by B cells to an I-Ek-restricted, THMc-specific T cell hybrid when covalently coupled to antibodies specific for B cell surface Ig, Ia (Ak), or class I (Kk). Maximal activation of the T cells to the THMcCys92-103-antibody conjugates is achieved with 1/100-1/1,000th of the peptide required using unconjugated THMcCys92-103 or THMcCys92-103 coupled to nonspecific antibody. The T cell response to the peptide antibody conjugates is MHC restricted, but unlike native cytochrome c-antibody conjugates, THMcCys92-103-antibody conjugates do not require processing and can be presented by paraformaldehyde-fixed B cells. The THMcCys92-103-antibody conjugate are nearly as effective when incubated with B cells, and the unbound conjugates washed away before addition of T cells as when continuously present in culture with T cells and B cells, indicating that the active peptide antibody conjugate is associated at the B cell surface. The presentation of THMcCys92-103 coupled to monovalent Fab fragments of rabbit anti-Ig antibodies is less effective than that of the peptide coupled to bivalent antibody when either live or fixed B cells are APC, indicating that the avidity for the APC surface afforded by bivalent binding may be important in the conjugate's antigenicity. The results presented here indicate that a T cell-antigenic peptide, covalently coupled to a larger antibody molecule, can be readily recognized by an Ia-restricted helper T cell in the absence of processing. Moreover, the ability of the peptide to bind to B cell surfaces greatly augments the peptide's antigenicity, even when the binding is to structures distinct from the Ia molecule required for T cell activation.

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3078-3078
Author(s):  
Diane L Rossi ◽  
Edmund A Rossi ◽  
David M Goldenberg ◽  
Chien-Hsing Chang

Abstract Background Various formats of bispecific antibodies (bsAbs) to redirect effector T cells for the targeted killing of tumor cells have shown considerable promise both pre-clinically and clinically. The scFv-based constructs, including BiTE and DART, which bind monovalently to CD3 on T cells and to the target antigen on tumor cells, exhibit fast blood clearance and neurological toxicity due to their small size (∼55 kDa). Herein, we describe the generation of novel T-cell redirecting trivalent bsAbs comprising an anti-CD3 scFv covalently conjugated to a stabilized F(ab)2. The design was initially characterized with a prototype construct designated (19)-3s, which specifically targets CD19 on B cells. A panel of trivalent bsAbs was evaluated for their potential use in targeted T-cell immunotherapy of various B-cell malignancies. Potential advantages of this design include bivalent binding to tumor cells, a larger size (∼130 kDa) to preclude rapid renal clearance and penetration of the blood-brain barrier, and potent T-cell mediated cytotoxicity. Methods The DOCK-AND-LOCKTM (DNLTM) method was used to generate a panel of B-cell targeting bsAbs, (19)-3s, (20)-3s, (22)-3s, and (C2)-3s, which target CD19, CD20, CD22, and HLA-DR, respectively. This was achieved by combining a stabilized anti-X F(ab)2 with an anti-CD3-scFv, resulting in a homogeneous covalent structure of the designed composition, as shown by LC-MS, SE-HPLC, ELISA, SDS-PAGE, and immunoblot analyses. Each construct can mediate the formation of immunological synapses between T cells and malignant B cells, resulting in T-cell activation. At an E:T ratio of 10:1, using isolated T cells as effector cells, the bsAbs induced potent T-cell-mediated cytotoxicity in various B-cell malignancies, including Burkitt lymphomas (Daudi, Ramos, Namalwa), mantle cell lymphoma (Jeko-1), and acute lymphoblastic leukemia (Nalm-6). A non-tumor binding control, (14)-3s, induced only moderate T-cell killing at >10 nM. The nature of the antigen/epitope, particularly its size and proximity to the cell surface, appears to be more important than antigen density for T-cell retargeting potency (Table 1). It is likely that (20)-3s is consistently more potent than (19)-3s and (C2)-3s, even when the expression of CD19 or HLA-DR is considerably higher than CD20, as seen with Namalwa and Jeko-1, respectively. This is likely because the CD20 epitope comprises a small extracellular loop having close proximity to the cell surface. When compared directly using Daudi, (22)-3s was the least potent. Compared to CD19 and CD20, CD22 is expressed at the lowest density, is a rapidly internalizing antigen, and its epitope is further away from the cell surface; each of these factors may contribute to its reduced potency. Finally, sensitivity to T-cell retargeted killing is cell-line-dependent, as observed using (19)-3s, where Raji (IC50 >3 nM) is largely unresponsive yet Ramos (IC50 = 2 pM) is highly sensitive, even though the former expresses higher CD19 antigen density. Conclusions (19)-3s, (20)-3s, (22)-3s, and (C2)-3s can bind T cells and target B cells simultaneously and induce T-cell-mediated killing in vitro. The modular nature of the DNL method allowed the rapid production of several related conjugates for redirected T-cell killing of various B-cell malignancies, without the need for additional recombinant engineering and protein production. The close proximity of the CD20 extracellular epitope to the cell surface results in the highest potency for (20)-3s, which is an attractive candidate bsAb for use in this platform. We are currently evaluating the in vivo activity of these constructs to determine if this novel bsAb format offers additional advantages. Disclosures: Rossi: Immunomedics, Inc.: Employment. Rossi:Immunomedics, Inc.: Employment. Goldenberg:Immunomedics: Employment, stock options, stock options Patents & Royalties. Chang:Immunomedics, Inc: Employment, Stock option Other; IBC Pharmaceuticals, Inc.: Employment, Stock option, Stock option Other.


1999 ◽  
Vol 73 (5) ◽  
pp. 4120-4126 ◽  
Author(s):  
Annette Oxenius ◽  
Marianne M. A. Martinic ◽  
Hans Hengartner ◽  
Paul Klenerman

ABSTRACT Synthetic nonmethylated oligonucleotides containing CpG dinucleotides (CpG-ODNs) have been shown to exhibit immunostimulatory activity. CpG-ODNs have the capacity to directly activate B cells, macrophages, and dendritic cells, and we show here that this is reflected by cell surface binding of oligonucleotides to these cell subsets. However, T cells are not directly activated by CpG-ODNs, which correlates with the failure to bind to the T-cell surface. Efficient competition for CpG-induced B-cell activation by non-CpG-containing oligonucleotides suggests that oligonucleotides might bind to an as yet undefined sequence-nonspecific receptor prior to cellular activation. Induction of protective T-cell responses against challenge infection with lymphocytic choriomeningitis virus (LCMV) or with recombinant vaccinia virus expressing the LCMV glycoprotein was achieved by immunizing mice with the immunodominant major histocompatibility complex class I-binding LCMV glycoprotein-derived peptide gp33 together with CpG-ODNs. In these experiments, B cells, potentially serving as CpG-ODN-activated antigen-presenting cells (APCs), were not required for induction of protective immunity since CpG-ODN–gp33-immunized B-cell-deficient mice were equally protected against challenge infection with both viruses. This finding suggested that macrophages and/or dendritic cells were sufficiently activated in vivo by CpG-ODNs to serve as potent APCs for the induction of naive T cells. Furthermore, treatment with CpG-ODN alone induced protection against infection with Listeria monocytogenes via antigen-independent activation of macrophages. These data suggest that CpG activation of macrophages and dendritic cells may provide a critical step in CpG-ODN adjuvant activity.


2005 ◽  
Vol 79 (11) ◽  
pp. 7255-7261 ◽  
Author(s):  
Maria Kotsiopriftis ◽  
Jerome E. Tanner ◽  
Caroline Alfieri

ABSTRACT The aim of this study was to elucidate the in vitro response of γδ T cells to Epstein-Barr virus (EBV)-infected B cells and to determine whether EBV-induced heat shock proteins (HSPs) might serve as γδ T-cell stimulants. Cytofluorometric analysis revealed HSP90 cell surface expression in 12% of the EBV-immortalized B-cell population in all four of the B-cell lines tested. HSP27, HSP60, and HSP70 were not detected on the cell surface by cytofluorometry in these same B-cell lines. HSP90 and HSP60, but not HSP70 or HSP27, were detected on the cell surface after 125I cell surface labeling and immunoprecipitation with anti-human HSP monoclonal antibodies. In vitro kinetic studies indicated that γδ T cells increased at least twofold by day 11 postinfection in cultures of EBV-seronegative peripheral blood lymphocytes infected with EBV, whereas percentages of αβ T cells in these same cultures either decreased slightly or remained relatively unchanged in response to EBV infection. Addition of anti-human HSP90 monoclonal antibody to the EBV-infected lymphocyte cultures inhibited γδ T-cell expansion by 92%. The inhibition of γδ T-cell expansion by anti-HSP90 antibody was reversed upon treatment with exogenous HSP90. Taken together, these results indicate that HSP90 played an important role in the stimulation of γδ T cells during EBV infection of B cells in vitro and may serve as an important immunomodulator of γδ T cells during acute EBV infection.


2021 ◽  
pp. annrheumdis-2021-220435
Author(s):  
Theresa Graalmann ◽  
Katharina Borst ◽  
Himanshu Manchanda ◽  
Lea Vaas ◽  
Matthias Bruhn ◽  
...  

ObjectivesThe monoclonal anti-CD20 antibody rituximab is frequently applied in the treatment of lymphoma as well as autoimmune diseases and confers efficient depletion of recirculating B cells. Correspondingly, B cell-depleted patients barely mount de novo antibody responses during infections or vaccinations. Therefore, efficient immune responses of B cell-depleted patients largely depend on protective T cell responses.MethodsCD8+ T cell expansion was studied in rituximab-treated rheumatoid arthritis (RA) patients and B cell-deficient mice on vaccination/infection with different vaccines/pathogens.ResultsRituximab-treated RA patients vaccinated with Influvac showed reduced expansion of influenza-specific CD8+ T cells when compared with healthy controls. Moreover, B cell-deficient JHT mice infected with mouse-adapted Influenza or modified vaccinia virus Ankara showed less vigorous expansion of virus-specific CD8+ T cells than wild type mice. Of note, JHT mice do not have an intrinsic impairment of CD8+ T cell expansion, since infection with vaccinia virus induced similar T cell expansion in JHT and wild type mice. Direct type I interferon receptor signalling of B cells was necessary to induce several chemokines in B cells and to support T cell help by enhancing the expression of MHC-I.ConclusionsDepending on the stimulus, B cells can modulate CD8+ T cell responses. Thus, B cell depletion causes a deficiency of de novo antibody responses and affects the efficacy of cellular response including cytotoxic T cells. The choice of the appropriate vaccine to vaccinate B cell-depleted patients has to be re-evaluated in order to efficiently induce protective CD8+ T cell responses.


1973 ◽  
Vol 138 (6) ◽  
pp. 1289-1304 ◽  
Author(s):  
David H. Sachs ◽  
James L. Cone

Antibodies cytotoxic for only a subpopulation of C57Bl/10 lymph node and spleen cells were detected when rat antiserum against B10.D2 was exhaustively absorbed with B10.A lymphocytes. Antibodies of similar specificity were also detected in B10.A anti-B10.D2 and in B10.A anti-C57Bl/10 alloantisera. Reactions with recombinant strains of mice indicate that the cell-surface antigen(s) responsible for this specificity is determined by gene(s) in or to the left of the Ir-1 region of the major histocompatibility complex. A variety of criteria implicate B cells as the subpopulation of lymphocytes bearing this antigen. In view of these data and the recent report by others of a T-cell alloantigen determined by gene(s) in the major histocompatibility complex, it seems possible that there may be a variety of H-2-linked alloantigens expressed preferentially on subclasses of lymphocytes.


1991 ◽  
Vol 173 (6) ◽  
pp. 1433-1439 ◽  
Author(s):  
R H Lin ◽  
M J Mamula ◽  
J A Hardin ◽  
C A Janeway

A novel mechanism for breaking T cell self tolerance is described. B cells induced to make autoantibody by immunization of mice with the non-self protein human cytochrome c can present the self protein mouse cytochrome c to autoreactive T cells in immunogenic form. This mechanism of breaking T cell self tolerance could account for the role of foreign antigens in breaking not only B cell but also T cell self tolerance, leading to sustained autoantibody production in the absence of the foreign antigen.


2002 ◽  
Vol 361 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Silvia GINÉS ◽  
Marta MARIÑO ◽  
Josefa MALLOL ◽  
Enric I. CANELA ◽  
Chikao MORIMOTO ◽  
...  

The extra-enzymic function of cell-surface adenosine deaminase (ADA), an enzyme mainly localized in the cytosol but also found on the cell surface of monocytes, B cells and T cells, has lately been the subject of numerous studies. Cell-surface ADA is able to transduce co-stimulatory signals in T cells via its interaction with CD26, an integral membrane protein that acts as ADA-binding protein. The aim of the present study was to explore whether ADA—CD26 interaction plays a role in the adhesion of lymphocyte cells to human epithelial cells. To meet this aim, different lymphocyte cell lines (Jurkat and CEM T) expressing endogenous, or overexpressing human, CD26 protein were tested in adhesion assays to monolayers of colon adenocarcinoma human epithelial cells, Caco-2, which express high levels of cell-surface ADA. Interestingly, the adhesion of Jurkat and CEM T cells to a monolayer of Caco-2 cells was greatly dependent on CD26. An increase by 50% in the cell-to-cell adhesion was found in cells containing higher levels of CD26. Incubation with an anti-CD26 antibody raised against the ADA-binding site or with exogenous ADA resulted in a significant reduction (50–70%) of T-cell adhesion to monolayers of epithelial cells. The role of ADA—CD26 interaction in the lymphocyte—epithelial cell adhesion appears to be mediated by CD26 molecules that are not interacting with endogenous ADA (ADA-free CD26), since SKW6.4 (B cells) that express more cell-surface ADA showed lower adhesion than T cells. Adhesion stimulated by CD26 and ADA is mediated by T cell lymphocyte function-associated antigen. A role for ADA—CD26 interaction in cell-to-cell adhesion was confirmed further in integrin activation assays. FACS analysis revealed a higher expression of activated integrins on T cell lines in the presence of increasing amounts of exogenous ADA. Taken together, these results suggest that the ADA—CD26 interaction on the cell surface has a role in lymphocyte—epithelial cell adhesion.


1980 ◽  
Vol 152 (5) ◽  
pp. 1274-1288 ◽  
Author(s):  
P Marrack ◽  
J W Kappler

The mode of action by bystander helper T cells was investigated by priming (responder X nonresponder) (B6A)F1 T cells with poly-L-(Tyr, Glu)-poly-D,L-Ala--poly-L-Lys [(TG)-A--L] and titrating the ability of these cells to stimulate an anti-sheep red blood cell (SRBC) response of parental B cells and macrophages in the presence of (TG)-A--L. Under limiting T cell conditions, and in the presence of (TG)-A--L, (TG)-A--L-responsive T cells were able to drive anti-SRBC responses of high-responder C57BL/10.SgSn (B10) B cells and macrophages (M0), but not of low-responder (B10.A) B cells and M0. Surprisingly, the (TG)-A--L-driven anti-SRBC response of B10.A B cells was not restored by addition of high-responder acessory cells, in the form of (B6A)F1 peritoneal or irradiated T cell-depleted spleen cells, or in the form of B10 nonirradiated T cell-depleted spleen cells. These results suggested that (TG)-A--L-specific Ir genes expressed by B cells controlled the ability of these cells to be induced to respond to SRBC by (TG)-A--L-responding T cells, implying that direct contact between the SRBC-binding B cell precursor and the (TG)-A--L-responsive helper T cells was required. Analogous results were obtained for keyhold limpet hemocyanin (KLH)-driven bystander help using KLH-primed F1 T cells restricted to interact with cells on only one of the parental haplotypes by maturing them in parental bone marrow chimeras. It was hypothesized that bystander help was mediated by nonspecific uptake of antigen [(TG)-A--L or KLH] by SRBC-specific b cells and subsequent display of the antigen on the B cell surface in association with Ir of I-region gene products, in a fashion similar to the M0, where it was then recognized by helper T cells. Such an explanation was supported by the observation that high concentrations of antigen were required to elicit bystander help. This hypothesis raises the possibility of B cell processing of antigen bound to its immunoglobulin receptor and subsequent presentation of antigen to helper T cells.


2022 ◽  
Vol 11 (1) ◽  
pp. 270
Author(s):  
Martina Hinterleitner ◽  
Clemens Hinterleitner ◽  
Elke Malenke ◽  
Birgit Federmann ◽  
Ursula Holzer ◽  
...  

Immune cell reconstitution after stem cell transplantation is allocated over several stages. Whereas cells mediating innate immunity recover rapidly, adaptive immune cells, including T and B cells, recover slowly over several months. In this study we investigated kinetics and reconstitution of de novo B cell formation in patients receiving CD3 and CD19 depleted haploidentical stem cell transplantation with additional in vivo T cell depletion with monoclonal anti-CD3 antibody. This model enables a detailed in vivo evaluation of hierarchy and attribution of defined lymphocyte populations without skewing by mTOR- or NFAT-inhibitors. As expected CD3+ T cells and their subsets had delayed reconstitution (<100 cells/μL at day +90). Well defined CD19+ B lymphocytes of naïve and memory phenotype were detected at day +60. Remarkably, we observed a very early reconstitution of antibody-secreting cells (ASC) at day +14. These ASC carried the HLA-haplotype of the donor and secreted the isotypes IgM and IgA more prevalent than IgG. They correlated with a population of CD19− CD27− CD38low/+ CD138− cells. Of note, reconstitution of this ASC occurred without detectable circulating T cells and before increase of BAFF or other B cell stimulating factors. In summary, we describe a rapid reconstitution of peripheral blood ASC after CD3 and CD19 depleted haploidentical stem cell transplantation, far preceding detection of naïve and memory type B cells. Incidence before T cell reconstitution and spontaneous secretion of immunoglobulins allocate these early ASC to innate immunity, eventually maintaining natural antibody levels.


Blood ◽  
1988 ◽  
Vol 71 (4) ◽  
pp. 1012-1020 ◽  
Author(s):  
JS Moore ◽  
MB Prystowsky ◽  
RG Hoover ◽  
EC Besa ◽  
PC Nowell

The consistent occurrence of T cell abnormalities in patients with B cell chronic lymphocytic leukemia (B-CLL) suggest that the non- neoplastic host T cells may be involved in the pathogenesis of this B cell neoplasm. Because potential defects of immunoglobulin regulation are evident in B-CLL patients, we investigated one aspect of this by studying the T cell-mediated immunoglobulin isotype-specific immunoregulatory circuit in B-CLL. The existence of class-specific immunoglobulin regulatory mechanisms mediated by Fc receptor-bearing T cells (FcR + T) through soluble immunoglobulin binding factors (IgBFs) has been well established in many experimental systems. IgBFs can both suppress and enhance B cell activity in an isotype-specific manner. We investigated the apparently abnormal IgA regulation in a B-CLL patient (CLL249) whose B cells secrete primarily IgA in vitro. Enumeration of FcR + T cells showed a disproportionate increase in IgA FcR + T cells in the peripheral blood of this patient. Our studies showed that the neoplastic B cells were not intrinsically unresponsive to the suppressing component of IgABF produced from normal T cells, but rather the IgABF produced by the CLL249 host T cells was defective. CLL249 IgABF was unable to suppress IgA secretion by host or normal B cells and enhanced the in vitro proliferation of the host B cells. Size fractionation of both normal and CLL249 IgABF by gel-filtration high- performance liquid chromatography (HPLC) demonstrated differences in the ultraviolet-absorbing components of IgABF obtained from normal T cells v that from our patient with defective IgA regulation. Such T cell dysfunction may not be restricted to IgA regulation, since we have found similar expansion of isotype-specific FcR + T cells associated with expansion of the corresponding B cell clone in other patients with B-CLL. These data suggest that this T cell-mediated regulatory circuit could be significantly involved in the pathogenesis of B-CLL.


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