bluuebunny/crossref_metadata_2025 huggingface dataset:
Degradation of specificity in cytolytic T lymphocyte clones: two broad specificity, H‐2‐independent recognition systems, one natural killer‐like, develop during culture, in addition to the clonally distributed antigen‐specific receptor
Authors: Wilson Anne , Shortman Ken
Published: February 2007

Ly‐2+ CBA mouse T lymphocytes stimulated with concanavalin A in limiting dilution culture produce clones of cytotoxic T lymphocytes (CTL) which, although initially specific, eventually lyse a wide range of target cells. The nature of the recognition system for this apparently “nonspecific” cytolysis was examined using a range of tumor cells as labeled targets and as cold target inhibitors. Most syngeneic and allogeneic murine tumor cells were lysed but the degree of lysis varied, even for different sublines of the same tumor. All tumor cells cold target inhibited their own lysis, and cross‐inhibited lysis of other targets to varying degrees. The recognition stage of “nonspecific” cytolysis appeared to be independent of target cell H‐2 expression; some H‐2‐negative murine target cells were lysed and some were not, but all gave cold target inhibition of “nonspecific” cytolysis. Xenogeneic tumor cells were resistant to lysis, but some nevertheless gave cold target inhibition of the “nonspecific” cytolysis of murine targets. A study of the specificity of cold target cross‐inhibition revealed two distinct patterns of recognition which existed simultaneously in “nonspecific” CTL; one was like that of natural killer cells and was directed to targets such as YAC‐1, the other was distinct from that of natural killer cells and was directed to targets such as P815. Thus, murine CTL may express three distinct receptors, the clonally distributed, H‐Zrestricted, antigen‐specific T cell receptor and two different “broad‐range” receptors common to most clones.
A self‐Ia reactive T cell clone directly stimulates every hundredth B cell and helps antigen‐specific B cell responses
Authors: Saito Takashi , Rajewsky Klaus
Published: February 2007

A self‐I‐A reactive T cell clone has been isolated that proliferates in the presence of irradiated syngeneic spleen cells in mouse serum. The cells directly stimulate approximately every hundredth B cell, which includes small B cells, into both proliferation and antibody formation in the absence of added antigen. There is evidence to suggest that cells of this type are generally present in murine T cell populations. The cells may recognize self‐I‐A as such. We failed to obtain evidence, but cannot exclude that they recognize an antibody idiotype in addition. The clone also augments antigen‐specific antibody responses in vivo and in vitro in the presence of antigen. In the in vitro response to a T‐independent TI‐2 antigen, the T cells in co‐culture with B cells induced specifically the production of IgG1 antibodies, thus mimicking the function of major histocompatibility complex‐restricted, antigen‐specific helper T cells. However, IgG1 production was not observed when splenic T cells were added to this system. Thus, self‐I‐A reactive T cells, generally inactive in the system, may locally help B cell responses to antigens which the T cells do not themselves recognize. In such instances one might attribute to the T cells antigen or idiotype‐binding specificities which the cells in reality do not display.
Expression of complement factor H on the cell surface of the human monocytic cell line U937
Authors: Malhotra Vivek , Sim Robert B.
Published: February 2007

Binding assays and immunocytochemical staining with monoclonal antibodies against the human serum complement protein factor H indicate that factor H antigen is present on the surface of more than 95% of the cells of the human monocytic cell line U937. The antigen is uniformly distributed and there are 10000–15 000 copies/cell. Factor H antigen is strongly associated with the cell surface and is not removed by hypotonic or hypertonic washes. Factor H antigen has been isolated from surface radioiodinated and 35S biosynthetically labeled cells using polyclonal anti‐factor H‐Sepharose columns. The antigen is indistinguishable from serum factor H in molecular weight. Secretion of factor H by U937 cells was not detected using sensitive tests in which factor H secretion by monocytes was apparent. Phorbol myristate acetate stimulation of the cells had no effect on the average number of factor H molecules expressed. We conclude that factor H is synthesized by U937 cells, but is not secreted, and remains strongly associated with the cell surface. The surface‐bound factor H may function as a C3b receptor.
Ontogenic studies on the appearance of two classes of immunoglobulin‐forming cells in the spleen of the Aleutian skate, Bathyraja aleutica, a cartilaginous fish
Authors: Kobayashi Kunihiko , Tomonaga Susumu , Teshima Kazuyuki , Kajii Tadashi
Published: February 2007

We identified the presence in the Aleutian skate, Bathyraja aleutica, of two classes of immunoglobulins (Ig), a high molecular weight Ig analogous to mammalian IgM and a low molecular weight Ig, similarly to the spiny rasp skate, Raja kenojei, (Kobayashi, K. et al., Mol. Immunol. 1984. 22: 397), using an immunological cross‐reaction with the specific antisera to the spiny rasp skate Ig components. The antigenic similarity of the heavy chains of the Ig of the Aleutian skate and those of the spiny rasp skate was less than that between their light chains. Two types of Ig‐producing cells, one producing the high molecular weight and the other forming the low molecular weight Ig, were present in the spleen of embryos and adults in the Aleutian skate at a ratio of 5–6:4–5. The number of these Ig‐producing cells increased with advancing development of the embryos but was 1/20 to 1/50 of those of adults. Cells, each of which were capable of forming both classes of Ig, were found in the spleen of embryos but not in that of adults. These results suggested that the spleen of the Aleutian skate is the primary lymphoid organ for B lymphocyte differentiation and proliferation, possibly equivalent to the bursa of birds.
Bone marrow macrophages induced to antigen presentation by lymphokines interact selectively with distinct T cells
Authors: Fischer Hans‐Georg , Reske‐Kunz Angelika B. , Spaeth Eberhard , Rüde Erwin
Published: February 2007

In vitro matured bone marrow‐derived macrophages (BMMϕ), which represent a pure population of Mϕ, were shown to act as antigen‐presenting cells (APC) to the T cell clone ST2/K.9. This interaction was major histocompatibility complex restricted. Upon long‐term culture in macrophage colony‐stimulating factor, BMMϕ were activated for antigen presentation by a 48‐h pulse with lymphokine‐containing supernatant of concanavalin A‐stimulated rat spleen cells (Con A sup). The capacity of such activated Mϕ to function as APC decreased upon removal of Con A sup, and could be regenerated by a second pulse. This finding suggests that antigen presentation by mature Mϕ is a reversible function regulated by T cell factors. When the responsiveness of various T cell lines to antigen presented on BMMϕ or spleen cells was compared, distinct activation requirements were observed for different T cells since lymphokine‐activated BMMϕ were not capable of inducing antigen‐specific proliferation of all lines.
The ability of Ia and H‐2Kk‐bearing membranes to replace the antigen‐presenting cell in an H‐2Kkallogeneic cytotoxic T cell response
Authors: Weinberger Ofra , Herrmann Steven H. , Greenstein Julia L. , Mescher Matthew F. , Burakoff Steven J.
Published: February 2007

Induction of an allogeneic cytotoxic T lymphocyte (CTL) response is dependent, in part, on uptake and processing of the class I alloantigen by antigen‐presenting cells and subsequent Ia‐restricted recognition of the alloantigen by helper T cells, resulting in lymphokine production. The nature of the antigen‐processing event has been investigated using reconstituted membranes to replace the antigen‐presenting cells in the generation of a secondary allogeneic CTL response. Membranes were isolated from an Iad‐positive antigen presenting B cell lymphoma (D2N), detergent solubilized and then reconstituted together with affinity‐purified H‐2Kk antigen in the presence of protease inhibitors. These reconstituted vesicles, containing both syngeneic Ia and alloantigen, were able to induce the helper T cell arm of the CTL response in cultures depleted of antigen‐presenting cells. A variety of control experiments provided strong evidence that the helper T cells recognized the H‐2Kk, probably in its native form, in an Ia‐restricted manner on the vesicles, while the pre‐CTL can directly recognize H‐2Kk. Recognition was only effective if both the Ia and alloantigen were inserted into the same membrane bilayer. The results strongly suggest that the obligatory antigen processing event required for helper T cell recognition of alloantigen is simply the insertion of the alloantigen into the same membrane bilayer as the syngeneic Ia restricting element.
Insulin‐specific T cell hybridomas derived from (H‐2b × H‐2k)F1 mice preferably employ F1unique restriction elements for antigen recognition
Authors: Reske‐Kunz Angelika B. , Rude Erwin
Published: February 2007

T cell hybridomas of (B10 × B10.BR)F1 genotype with reactivity to bovine insulin (BI) were established to analyze the restriction and antigen fine specificity of (H‐2b × H‐2k)F1 T cells towards BI. Our data indicate a focusing of the response on two epitopes on the insulin molecule, the A chain loop determinant comprising amino acids A8 and A10, as well as the glutamic acid residue in position 4 of the A chain. Both were recognized either separately or in conjunction. Unexpectedly, the T cell hybridomas exhibited a marked preference for recognizing insulin in the context of F1‐unique restriction elements of A A type rather than parental high‐responder I‐Abmolecules. Analysis of the response of primed lymph node T cells of (B10 × B10.BR)F1 mice towards BI corroborated the finding of a preponderant corecognition of F1unique I‐A molecules.
The effects of cyclosporin on lymphocyte activation in a systemic graft‐vs.‐host reaction
Authors: Chisholm Patricia M. , Drayson Mark T. , Cox Josephine H. , Ford William L.
Published: February 2007

We have investigated the effects of cyclosporin (CsA) on each of three stages of lymphocyte activation in vivoviz. sequestration of alloantigen‐reactive lymphocytes from the circulation into the spleen and lymph nodes, blast transformation and induction of DNA synthesis in the activated cells and release of these cells and their progeny into the circulation. Parental strain lymphocytes injected i.v. into semiallogeneic rats and recovered from the thoracic duct within 36 h are profoundly unresponsive in a local graft‐vs.‐host assay to the alloantigens of the F1 hybrid but have normal activity against unrelated alloantigens (negative selection). CsA treatment of the F! hybrid recipients did not prevent this selective sequestration of antigen‐reactive cells. In the untreated FI hybrid, from 36 h after injection, large numbers of dividing blast cells were released into the lymph. These cells did not appear in the lymph of recipients treated with CsA. However, CsA did not prevent the activation of cells sequestered in the spleen or lymph nodes as assessed by [3H] thymidine incorporation and autoradiography. This unexpected finding suggests that CsA inhibits lymphocyte responses to alloantigens in vivo after DNA synthesis which is a later stage than the in vitro studies have shown.
Direct effect of interleukin 2 on the differentiation of human B cells which have not been preactivated in vitro
Authors: Bich‐Thuy LĚ Thi , Fauci Anthony S.
Published: February 2007

Unfractionated as well as small and large human tonsillar B cells were found to differentiate in the presence of recombinant interleukin 2 (IL 2) without requiring an in vitro preactivation signal. These cell suspensions did not contain detectable T cells, monocytes or natural killer cells both at the initiation and the termination of cultures, and did not respond to the T cell‐dependent polyclonal B cell activator pokeweed mitogen. They contained very few Tac antigen‐bearing cells (less than 2.5%) at the beginning and at the termination of the cultures in the absence of IL 2. In the presence of IL 2, only a minimal increase in the number of Tac antigen‐bearing cells was noted. The observed differentiation was not due to the effects of contaminating T cells, since cultures purposely contaminated with up to 5% of T cells did not contain greater amounts of IgM, IgG or IgA than cultures without T cells added back. Furthermore, when T cells were present at a ratio of IT cell per 9 B cells, the production of IgM was decreased. Taken together, these data support the hypothesis that (a) B cell differentiation in response to IL 2 may occur in the absence of in vitro preactivation, and in this case cannot be related to the expression of Tac antigen on the B cell surface; (b) it is not due to helper effects of very low numbers of T cells which might contaminate the B cell suspensions; and (c) it most likely results from a direct effect of IL 2 on B cells themselves. The data also point out the fact that, in the presence of IL 2, T cells may trigger inhibitory effects on IL2‐induced B cell differentiation rather than provide helper signals.
Biochemical and functional characteristics of the human leukocyte membrane antigen family LFA‐1, Mo‐1 and p!50,95
Authors: Keizer Gerrit D. , Borst Jannie , Figdor Carl G. , Spits Hergen , Miedema Frank , Terhorst Cox , de Vries Jan E.
Published: February 2007

The human leukocyte function‐associated (LFA‐1) antigen, the monocyte differentiation antigen Mo‐1 which is characterized as the C3bi receptor and the glycoprotein p150,95 are characterized biochemically. Immunoprecipitations carried out with 6 different monoclonal antibodies (mAb) against LFA‐1 indicated that four mAb (SPV‐ L1, SPV‐L5, SPV‐L7 and SPV‐L11) were directed against the a chain, whereas mAb CLB54 and MHM‐23 were found to react with the common β chain of LFA‐1, Mo‐1 and p150,95. LFA‐1 and Mo‐1 expressed on KG‐1 cells or lymphocytes, monocytes and granulocytes from one donor were homogeneous. Interestingly the a chain of p150,95 showed heterogeneity. The molecular weight of the a chain expressed on monocytes was consistently higher than that of the α chain on granulocytes. The β subunits of LFA‐1 and Mo‐1 (as detected by mAb Bear‐1) are not only similar in molecular weight and isoelectric focusing patterns, but it is demonstrated here that they are also identically glycosylated and have similar protein backbones as judged by tryptic peptide mapping. In spite of their structural similarities, LFA‐1 and Mo‐1 differ completely in some of their biological functions. Anti‐LFA‐1 mAb strongly inhibited monocyte‐dependent T cell proliferation induced by tetanus toxoid or Helix pomatia hemocyanin and pokeweed mitogen‐driven specific antibody production in vitro, whereas the anti‐Mo‐1 antibody Bear‐1 was ineffective. These results suggest that the differences in these biological functions of LFA‐1 and Mo‐1 may be related to their different a subunits, which may recognize specific counter structures.
Biosynthesis of complement protein D by HepG2 cells: a comparison of D produced by HepG2 cells, U937 cells and blood monocytes
Authors: Barnum Scott R. , Volanakis John E.
Published: February 2007

The biosynthesis of complement protein D of the alternative pathway by HepG2 cells, a human hepatocyte cell line, was studied and compared to the biosynthesis of D by U937 cells and blood monocytes. Increasing amounts of antigenic D were detected in HepG2 cell culture supernatants by radioimmunoassay. The kinetics of D synthesis and secretion by HepG2 cells was followed in a pulse‐chase study using [35S]cysteine. As analyzed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis followed by autoradiography, only a single D band was seen intra‐ and extracellularly and both forms had the same apparent molecular weight as D synthesized by U937 cells or purified from serum. Treatment of HepG2 and U937 cells with canavanine, an arginine amino acid analog, to inhibit intracellular processing resulted in slight depression of the apparent molecular weight of D synthesized by these cells. D synthesized by blood monocytes had an apparent molecular weight similar to that synthesized by HepG2 and U937 cells, suggesting that these cell lines do not synthesize and process D differently than normal monocytes. The data demonstrate that the hepatocyte is a site of D synthesis and suggest that D is not synthesized as a precursor molecule.
Monoclonal antibody 9.3 and anti‐CD11 antibodies define reciprocal subsets of lymphocytes
Authors: Yamada Hironori , Martin Paul J. , Bean Michael A. , Braun Marcus P. , Beatty Patrick G. , Sadamoto Kenichiro , Hansen John A.
Published: February 2007

We have previously described antibody 9.3 which recognizes a 44‐kDa polypeptide designated Tp44 expressed on 70‐80% of peripheral blood T cells, including nearly all CD4+ cells and some CD8+ cells. Whereas the 9.3+ population contains helper cells, cytotoxic T cell precursors and cytotoxic T cell effectors, the 9.3− population has been reported in several models to contain precursors for suppressor cells. In this report, we demonstrate that 9.3− lymphocytes express CD11, an antigen which is also present on monocytes and granulocytes. Among lymphoid cells, Tp44 and CD 11 represent markers that identify reciprocal, nonoverlapping subsets, each of which contains both CD8+ cells and CD4+ cells. With Tp44 and CD11, and CD4 and CDS, the development and function of T cells can thus be examined within the framework of two distinct systems of reciprocally expressed antigens.
Distribution of class IIDQ antigens on normal and leukemic lymphoid cells
Authors: Fermand Jean‐Paul , Schmitt Christian , Brouet Jean‐Claude
Published: February 2007

The distribution of DQ as well as DR antigens was examined on lymphoid and monocytic cells at different stages of differentiation. In the B cell series, both immature and differentiating (under Staphylococcus aureus or pokeweed mitogen stimulation) B cells often lacked DQ molecules; among surface IgM+ and IgD+ cells, both DQ and DR molecules were detected except on cells from 30% of the lymphoid malignancies studied. T cells expressed DQ molecules only after stimulation; a DQ−DR+ phenotype was observed in a large number of cells after allogeneic stimulation, in certain antigen‐specific T cell lines as well as in T cell lymphomas, suggesting that class II antigens had a distinct pattern of regulation. In the monocytic lineage, DQ molecules were expressed by most lymph node monocytes and only a low percentage (20%) of circulating monocytes.
gp140, a C3b‐binding membrane component of lymphocytes, is the B cell C3dg/C3d receptor (CR2) and is distinct from the neutrophil C3dg receptor (CR4)
Authors: Frade Raymond , Myones Barry L. , Barel Monique , Krikorian Laure , Charriaut Christiane , Ross Gordon D.
Published: February 2007

gp140, previously identified as a 140‐kDa C3b‐binding membrane glycoprotein present on Raji cell surface, was shown to be the C3dg/C3d receptor of B lymphocytes (CR2). Specific polyclonal anti‐gpl40, prepared by immunizing rabbits with this highly purified C3 receptor, blocked Raji cell rosettes with EC3b, EC3bi, EC3dg and EC3d, and also blocked normal lymphocyte rosettes with EC3dg and EC3d without affecting CR1 or CR3 activity. Moreover, a monoclonal anti‐C3 (C3b/#130), described by others as reacting with the d region highly expressed on ECSbi, EC3dg and EC3d and poorly exposed on EC3b, completely inhibited EC3bi, EC3dg and EC3d rosettes with Raji cells, but had no effect on EC3b rosettes. Treatment of Raji cells with rabbit anti‐gp140 blocked the uptake of three 125I‐labeled monoclonal antibodies anti‐B2, HB‐5 and OKB7 reported to react with C3d‐binding proteins, indicating that each of these monoclonal antibodies recognizes epitopes present on gp140.

The neutrophil C3dg receptor was examined to determine its relationship to lymphocyte CR2. While neutrophil rosettes with EC3d were undetectable, a specificity for C3d was suggested by the inhibition of EC3dg rosettes by fluid phase C3d‐complexes bearing no detectable C3dg. However, such neutrophil EC3dg and EC3bi rosettes were not inhibited by rabbit anti‐gp140 nor an excess of anti‐CRl, anti‐CR2, and anti‐CR3. In addition, neutrophils did not bind 125I‐labeled anti‐gp140, anti‐B2, or HB‐5. Thus, the neutrophil C3dg receptor is distinct from gp140, the lymphocyte CR2, and should be designated CR4.
Epitope‐specific regulation of the T cell repertoire: carrier recognition in association with I‐E or I‐A does not influence the restriction of hapten‐specific T cells
Authors: Trannoy Emanuelle , Regnier Daniel , Campbell Helen , Seman Michel
Published: February 2007

The T cell repertoire of BALB/c mice contains clones capable of recognizing p‐azobenzenearsonate (ABA)‐tyrosine (Tyr) in association with both I‐A and I‐E‐encoded class II molecules. Immunization of BALB/c animals with ABA‐GAT (ter‐polymer of L‐Glu60‐L‐Ala30‐L‐Tyr10) or ABA‐GLT (terpolymer of L‐Glu51‐L‐Lys34‐L‐ Tyr15) instead of ABA‐Tyr reduces the secondary proliferative response to ABA‐Tyr in vitro. Limiting dilution experiments indicate that this situation corresponds to the recruitment of fewer ABA‐specific T cells in vivo. The same experiments, performed in A.TH mice, which are nonresponder to both GAT and GLT, demonstrate that the number of ABA‐specific T cells stimulated in vivo with ABA conjugates depends on the Ir gene‐controlled immunogenicity of the carrier rather than on the ABA epitope density on the immunogen. Although GAT is preferentially recognized in association with A, and GLT with E, ABA‐GAT and ABA‐GLT stimulate both A and E‐restricted ABA T cells in vivo and in vitro. The ABA‐Tyr‐specific T cell repertoire is not qualitatively affected by the carrier. This demonstrates that the inhibition of hapten‐specific T cell expression upon immunization with ABA conjugates does not result from a competition between hapten and carrier‐specific T cells for epitope recognition in association with the same la molecule on antigen‐presenting cells.
Immunologically discrete conformation isomers of I‐A locus‐equivalent class II molecules detected in Lewis rats
Authors: Reske Konrad , Weitzel Rainer
Published: February 2007

Monoclonal antibodies MRC‐OX6 and MRC‐OX3 were used to define biosyntheti‐cally inter‐related subsets of I‐A‐equivalent class II molecules from Lewis rat spleen cells. MRC‐OX6 was shown to recognize specifically multiple forms of the class II molecule arising along its maturation pathway from the origin of polypeptide chain synthesis, the rough endoplasmatic reticulum, through the Golgi compartment to the plasma membrane. Three MRC‐OX6‐reactive polypeptide chain complexes were distinguished: (a) an early complex composed of immature components of the polymorphic α, β heterodimer in noncovalent association with immature proteins of the invariant γ‐chain group p40, p33 (γ), p28, p20; (b) a biosynthetic intermediate comprising the subunits α,β and γ all of them being extensively glycosylated and sialy‐lated. The latter constituent is referred to as p36; (c) a cell surface structure consisting of the mature α, β heterodimer devoid of the mature invariant chain p36. A two‐dimensional (2D) separation pattern exhibited by an MRC‐OX6‐specific immunoprecipitate from spleen cells labeled for 4 h represents a superposition of these three MRC‐OX6‐reactive polypeptide chain complexes. In contrast, MRC‐OX3 recognizes exclusively a fully mature aα,β heterodimer devoid of protein precursor forms and devoid of any invariant chains. Considering the previous observation that the respective α and β subunits of MRC‐OX6 and MRC‐OX3‐specific molecules comigrate on 2D O'Farrell gels combined with the data of this investigation, it is suggested that the mature MRC‐OX6‐specific α,β heterodimer and the mature MRC‐OX3‐specific α,β heterodimer originate from the same biosynthetic intermediate. We propose that before entering the plasma membrane an MRC‐OX6‐reactive molecule composed of fully glycosylated α,β and p36 releases its post‐translationally processed γ chain (p36), giving rise to two conformation isomers, one α,β heterodimer still being reactive with MRC‐OX6 and one α,β heterodimer which has lost the serologic MRC‐OX6 and gained the MRC‐OX3 specificity. Both α,β heterodimers are expressed on the cell surface as two distinct subsets of I‐A‐equivalent class II molecules.
Three distinct subpopulations of sheep T lymphocytes
Authors: Mackay Charles Reay , And Jillian Fay Maddox , Brandon Malcolm Roy
Published: February 2007

Monoclonal antibodies reactive with distinct T lymphocyte subpopulations have been described in man, mouse and rat and structural analyses of these antigens have demonstrated a high degree of evolutionary conservation. This report describes the reactivity of three monoclonal antibodies (mAb), 19–19, αSBU‐T4 and αSBU‐T8, which define T cell subpopulations in the sheep. The mAb αSBU‐T4 and αSBU‐T8 define the sheep CD4 and CD8 molecules, respectively. These two antigens show similar tissue distributions, molecular weights and fluorescence‐activated cell sorter profiles to human, mouse and rat CD4 and CD8 molecules. The mAb 19–19 is reactive with a subpopulation of T lymphocytes which displays a tissue distribution unlike that reported for a T cell subset in any other species. 19–19 stains 7% of efferent lymph lymphocytes, 15% of peripheral blood lymphocytes but only 1–3% of lymph node lymphocytes. Two‐color immunofluorescence demonstrates that the 19–19+ T cell subset is SBU‐T4− and SBU‐T8−, and thus defines a third T cell subpopulation in sheep. Immunohistology on frozen lymph node tissue sections localizes 19–19 mAb‐reactive cells to the subcapsular region of the lymph node and lymph node trabeculae. Only 1% of thymocytes are 19–19+ and these cells are located mainly in the medulla and often arranged as foci around blood vessels. The 19–19 mAb immunoprecipitates from sheep lymphocytes an antigen with an apparent molecular mass of 215 kDa under both reducing and nonreducing conditions. It is concluded that αSBU‐T4 and αSBU‐T8 recognize the sheep homologues of the human T4 and T8 antigens, respectively, whereas 19–19 recognizes an antigen (termed SBU‐T19) which has not been reported in any other species.
Antibody affinity maturation in selectively bred high and low‐affinity mice
Authors: Steward Michael W. , Stanley Carolynne , Furlong Maria D.
Published: February 2007

The affinity of serum antibodies produced by selectively bred lines of mice [high affinity, low affinity, low nonmaturing (N/M)] injected with T‐dependent [human serum albumin (HSA), dinitrophenylated bovine γ‐globulin (DNP‐BGG)] and T‐independent (DNP‐Ficoll) antigens in saline and adjuvant has been determined. The lines of mice differ significantly in the affinity of antibody produced to T‐dependent antigens injected in saline but not to the T‐independent antigen. Unlike mice of the high and low‐affinity lines, low‐affinity N/M mice failed to show affinity maturation to HSA and DNP‐BGG injected in Freund's incomplete adjuvant. However, low‐N/M mice responded to DNP‐Ficoll injected in adjuvant by the production of antibody of affinity comparable to that produced in the other lines and with a similar maturation in affinity. Carrier priming resulted in the suppression of anti‐hapten antibody affinity in all lines but low‐N/M mice showed significantly greater suppression late in the response to challenge. Low doses of cyclophosphamide produced a significant increase in affinity in low‐N/M mice. These results suggest that the failure of low‐N/M mice to show affinity maturation results from increased suppressor T cell activity. The availability of the selectively bred mice provides a useful model for the detailed study of the cellular basis of the control of antibody affinity maturation.
Induction of rheumatoid factors in mice by immune complexes of bacterial lipopolysaccharide with mouse IgG antibody
Authors: Kanoh Makoto , Utsumi Sayaka , Hino Tomoo
Published: February 2007

Administration of 2,4,6‐trinitrophenylated E. coli lipopolysaccharide (TNP‐LPS) complexed with mouse IgG antibody to TNP specifically gave rise to a marked production of rheumatoid‐like factors (RF) in the recipient mice, in contrast to the low and nonspecific RF production via polyclonal B cell activation by the same dosage of LPS or TNP‐LPS alone. The RF activity induced by the LPS immune complexes was associated with both IgG and IgM and directed primarily to the Cγ2 region as judged by the heterophilic reactivity toward fragments of rabbit IgG. The results suggest that antibody molecules attached to LPS constitute novel epitopic groups on the mitogenic carrier and stimulate B cells in a specific manner to induce the autoantibodies.
A protective human monoclonal IgA antibody produced in vitro: Anti‐pneumococcal antibody engendered by Epstein‐Barr virus‐immortalized cell line
Authors: Steinitz Michael , Tamir Sara , Ferne Mina , Goldfarb Ada
Published: February 2007

Human lymphocytes that produce anti‐pneumococcal antibodies were separated and immortalized by Epstein‐Barr virus and then cloned. One clone (NAD‐Sel) produces an IgA, x antibody which is specific for the polysaccharides of type 8 pneumococcus, while not reactive with any of the polysaccharides derived from 24 other pneumococcal strains. The antibody, which is present in the cell supernatant as monomer and polymer, binds to protein A and does not fix complement. When incubated in vitro with type 8 pneumococci, it induces direct killing and increases the opsonization of these bacteria by mouse macrophages.
Defective membrane expression of the LFA‐1 complex may be secondary to the absence of the β chain in a child with recurrent bacterial infection
Authors: Lisowska‐Grospierre Barbara , Bohler Marie‐Christine , Fischer Alain , Mawas Claude , Sringer Thymothy A. , Giscelli Claude
Published: February 2007

Membrane and intracellular processing of the LFA‐1 macromolecular complex, known to be involved in cytolytic function of T lymphocytes, was investigated in a child with recurrent bacterial infections, impaired natural killer activity, T cell‐mediated lymphocytolysis and absent adhesion and migration of phagocytic cells. Monoclonal antibodies to the LFA‐1 α and β subunits, able to precipitate the LFA‐1α, 180‐kDa chain, the p151 chain and β 94‐kDa chain (shared by both α chains), were used in immunoprecipitation studies of patient and control phytohemagglutinin‐blasts. Neither of the α chains nor the β chain were found in precipitates obtained from 125I‐surface‐labeled patient cells in contrast to controls. However, the precursor of the LFA‐1 α chain, a 170‐kDa polypeptide, was identified in lysates of biosynthetically labeled patients' cells. These results suggest that the defective membrane expression of the LFA‐1 complex may be secondary to the absence of the mature β chain.
Biochemical characterization of chicken secretory component
Authors: Peppard Jane V. , Hobbs Stephen M. , Jackson L. Elizabeth , Rose M. Elaine , Mockett Adrian P. A.
Published: February 2007

Human dimeric IgA was injected i.v. into chickens whose bile was then collected. The human IgA which had been transported across the hepatocytes of the chicken was subsequently purified from the bile and shown to be associated with a protein of 80 kDa and pI 4.6, which reacted with rabbit antisera to chicken bile proteins but not with an antiserum to human α chain. The chicken bile protein thus has functional and biochemical properties similar to those of mammalian secretory component.
Activation of resting T lymphocytes by a monoclonal antibody directed against an allotypic determinant on the T cell receptor
Authors: Staerz Uwe D. , Bevan Michael J.
Published: February 2007

The murine monoclonal antibody F23.1 reacts with an allotypic determinant on the β chain of the T cell receptor expressed by approximately 20% of T helper and cytotoxic T lymphocytes of most common mouse strains. This IgG2a antibody, either in soluble form or covalently coupled to Sepharose beads, can activate resting T cells from naive animals to proliferate. Interestingly, under all conditions of activation, the antibody can only induce proliferation if exogenous lymphokines in the form of Con A supernatant are provided. Thus, it is unlike most lectins and anti‐T3 antibodies in this regard. Furthermore, under all conditions of culture, F23.1 activates preferentially the Lyt‐2+ subset of T cells. This is the case even in the presence of accessory cells. Further evidence is provided that two soluble lymphokines, different from IL2, are required to initiate IL2‐dependent growth and to allow the expression of lytic activity.
Influence of carriers on the development and localization of anti‐trinitrophenyl antibody‐forming cells in the murine spleen
Authors: Claassen Eric , Kors Nel , Rooijen Nico Van
Published: February 2007

Mice were i.v. immunized with various 2,4,6‐trinitrophenyl (TNP)‐carrier conjugates, and the development and localization of specific (i.e. anti‐TNP) antibody‐forming cells (AFC) in the spleen was studied. The nature of the carrier used, thymus dependent (TD) or thymus independent type 1 or type 2 (TI‐1, TI‐2), had marked effects on the number and time of appearance of AFC. However, no influence of the different carriers on the localization of specific AFC in the spleen was observed. By using a double immunocytochemical technique we could simultaneously determine specificity (anti‐TNP) and isotype (class and subclass) of the AFC. The TNP‐carrier conjugates evoked (intracellular) immunoglobulins with carrier‐characteristic isotype distribution. No carrier‐dependent localization pattern, in the lymphoid compartments of the spleen, of these AFC was found. These results show for the first time the actual in situ effects of various TI and TD carriers on the development of specific AFC. Based on the present findings, no direct evidence for a special role of the marginal zone in the immune response against TI‐2 antigens could be demonstrated. We suggest that this new method for in vivo investigation, in combination with existing standard enzyme‐ and immunohistochemical techniques, can provide more insight into the precise role of lymphoid and nonlymphoid cells in TD and TI immune responses.
Conformational‐dependent recognition of influenza virus hemagglutinin by murine T helper clones
Authors: Mills Kingston H. G. , Skehel John J. , Thomas D. Brian
Published: February 2007

A panel of H‐2k class II‐restricted T helper (Th) clones were established from individual CBA mice intranasally infected with A/X31 influenza virus. In a study of their fine specificity, it was revealed that recognition of hemagglutinin (HA) by certain Th clones was dependent on conformational features of the molecule. Five HA‐specific Th clones failed to recognize X31 mutant viruses R19 and R20 each with a His to Arg substitution at position 17 of HA1. This amino acid substitution affects the conformational stability of the molecule. Each of the 5 clones responded to purified HA but failed to recognize tryptic fragments of HA consisting of HA1 residues 28–328 (tops) and the remainder of the virus including residues 1–27 of HA1 (aggregate). A further 20 HA‐specific clones responded to R19 and R20 mutants and to HA1 tops. The R19 and R20 negative clones also showed diminished proliferative responses to pH 5‐treated X31. Low pH treatment results in an irreversable conformational change which affects the integrity of the globular head region of the HA trimer. In addition, four of the five clones failed to recognize variant virus Eng‐72 which has Arg to Gly substitution at position 208 in the interface antibody‐binding region. This region is antigenically and structurally altered in tops and pH 5‐treated X31. The results suggest that recognition of HA by certain Th clones is dependent on the three‐dimensional structure of the molecule and that Th cells may recognize conformational determinants in addition to primary structure.
The cellular basis of salivary immunity in the mouse: Incidence and distribution of B cells, T cells and macrophages in single‐cell suspensions of the major salivary glands
Authors: Oudghiri Mounia , Seguin Jacynthe , Deslauriers Noëlla
Published: February 2007

A multiparametric analysis of the resident immune populations in the parotid, submandibular and sublingual salivary glands was done in single‐cell suspensions. The incidence of T and B cells and of macrophages was assessed using phenotypic markers in immunofluorescent staining and a functional assay was used to enumerate immunoglobulin (Ig)‐secreting cells. Characteristic frequencies and isotype distributions of cytoplasmic Ig+ B cells and surface Ig+ B lymphocytes were found in the three types of glands. Even though IgA was always found to be the predominant isotype in individual salivary secretions (90–93%) this was not directly correlated by an absolute predominance of IgA‐secreting cells in the glands (45–65%). Significant percentages of T cells (Thy‐1+ and Lyt‐1+ cells: 3–4%) and macrophages (Mac 1+ and esterase‐positive cells: 3–10%) were also recovered in our suspensions. It is therefore concluded that the murine salivary glands contain both effector and regulatory cells required for the development and expression of salivary immunity.
Internalization and processing of antibodies to surface antigens on human B cells. Monoclonal anti‐IgM antibodies are processed differently than monoclonal antibodies towards non‐Ig surface receptors
Authors: Ruud Erik , Blomhoff Heidi Kiil , Funderud Steinar , Godal Tore
Published: February 2007

The internalization and intracellular processing of monoclonal antibody to immunoglobulin μ heavy chain (Maμ) have been investigated in two human Burkitt lymphoma cell lines (Ramos and Raji), in a human B cell lymphoma and in normal human peripheral blood B cells. In addition to the degradation of 125I‐labeled Maμ to trichloroacetic acid (TCA) soluble material, a distinct pattern of larger 125I‐Map fragments was detected in all sources of B cells tested. The particular fragmentation pattern, as revealed by sodium dodecyl sulfate‐polyacrylamide gel electrophoretic analysis, involved the cleavage of both peptide bonds and disulfide bridges. This type of antibody fragmentation appeared to be a selective mechanism associated with sIgM, as no other degradation than that leading to TCA‐soluble material could be detected after the internalization and degradation of radiolabeled monoclonal antibodies towards a variety of non‐Ig B cell surface receptors. Three fragments of 125I‐Maμ degradation were also detected in the supernatant of Ramos cells, implying that the recycling and exocytosis of certain 125I‐Maμ fragments also took place.
Structural polymorphism of Vx21 E and Vx21 D gene products in laboratory mice
Authors: Primi Daniele , Barbier Eliane , Cazenave Pierre‐André
Published: February 2007

The aim of the present work was to study structural polymorphism of Vx genes products. To this end we isolated immunoglobulins expressing the Vx21 D and Vx21 E gene products from the normal sera of several inbred strains of mice using a monoclonal antibody that selectively recognizes Vx21 D and Vx21 E subgroups. Analysis of the isoelectric focusing pattern of the light chain of these immunoglobulins revealed the existence of 3 clearly different phenotypes. The first one is shared by most inbred strains of mice, the second one is expressed by C58/J, AKR and PL/J and the third one defines Vx21 D‐E light chains of SJL and SJA mice. Genetic analysis revealed that the locus controlling Vx21 D‐E chain structure is closely linked to the Ly2–3 and to the Igx‐Ef1 loci. Finally, using recombinant mouse strains, we could also order Vx21 D‐E genes with respect to the known loci affecting Vx polymorphism.

Taken together our data argue against the possibility that the polymorphism observed results from strain‐specific expression of Vx genes common to all mice, but rather suggest that different allelic form of the same Vx gene subgroup exist in different strains.
Adsorption on B cell hybridomas removes suppressor cells from spleen cells of neonatally tolerized mice
Authors: Stockinger Brigitta , Darjes Heidi , Krammer Peter H.
Published: February 2007

Spleen cells from CBA mice neonatally tolerized to Dd MHC (major histocompatibility complex) determinants were adsorbed on monolayers of Dd‐specific B cell hybridomas. Adsorption on 4 different Dd‐specific hybridomas but not on a Kd‐specific hybridoma removed suppressor cells and resulted in generation of cytotoxic T lymphocyte (CTL) effector cells against the tolerogen. Responses of normal CBA CTL against Dd as well as anti‐third party responses were not influenced by adsorption. Successful adsorption was also achieved on monolayers of fixed hybridoma cells. Monolayers of Dd‐specific hybridomas specifically removed suppressor cells from CBA mice tolerant to Dd; they failed to adsorb suppressor cells from AKR mice tolerant to H‐2b.

Immunofluorescence analysis with antibodies specific for determinants on tolerizing cells showed the presence of donor‐derived F1 cells on the monolayer. Under the experimental circumstances described suppressor cells are most likely removed by recognition of their MHC determinants by the monolayer population.

These data suggest that neonatal tolerance is actively maintained by donor‐derived suppressor cells.
Dissociation of interleukin 2‐dependent and ‐independent B cell proliferation with monoclonal anti‐interleukin 2 receptor antibody
Authors: Hashimoto Noboru , Nabholz Markus , MacDonald H. Robson , Zubler Rudolf H.
Published: February 2007

In a recent report from our laboratory (J. Exp. Med. 1984. 160: 1070), it has been shown that B cells which have been activated with lipopolysaccharide (LPS) plus anti‐Ig antibodies express interleukin 2 (IL2) receptors and proliferate in response to pure IL2. In the present study, we have investigated the role of IL2 during proliferative B cell responses supported by various T cell supernatants (SN) as well as by LPS itself. The following results were obtained: (a) B cells activated with LPS plus anti‐Ig were found to proliferate in response to either recombinant IL2, T cell SN or fresh LPS; (b) a monoclonal anti‐IL2 receptor antibody (PC61) could completely inhibit the effects of recombinant IL2 or various T cell SN (cloned T helper cell SN, EL4 SN, concanavalin A‐spleen cell SN or mixed leukocyte culture SN), but did not interfere with the effect of LPS; (c) B cells activated with LPS or LPS plus anti‐Ig were not found to secrete detectable amounts of IL2 by themselves.

Thus, the data demonstrate that LPS‐stimulated B cell proliferation requires neither B cell autocrine nor T cell‐derived IL2. On the other hand, with regard to LPS plus anti‐Ig‐activated B cells, IL2 appeared to be the only growth‐promoting activity that could be detected in the supernatants obtained from total normal spleen cell populations.
Production and characterization of rabbit anti‐idiotypic antibodies specific to mouse monoclonal anti‐human IgE and reacting with IgE‐binding factors and lymphocyte receptors for IgE
Authors: Sarfati Marie , Duncan Douglas , Delespesse Guy
Published: February 2007

A mouse monoclonal antibody specific to human IgE (mAb75) was employed to immunize a rabbit to obtain anti‐idiotypes (aId) bearing the internal image of human IgE determinants and reacting with IgE‐binding factors (IgE‐BF) and/or lymphocyte receptors for IgE (FcϵR). mAb75 was selected on the basis of inhibition assays where the binding of mAb 75 to radiolabeled IgE was blocked by IgE‐BF. The latter were produced by a lymphoblastoid cell line (RPMI 8866) expressing FcϵR. Sequential samples of rabbit serum, collected during the immunization period, were extensively absorbed on mouse and human Ig‐Sepharose 4B. The IgG fractions of the rabbit serum displayed the following activities: (a) they reacted with 125I‐labeled mAb 75 but not with other labeled mouse Ig including mAb‐aIgE, (b) this binding was inhibited in a dose‐dependent fashion by human IgE but not by other human Ig classes nor by heat‐inactivated IgE, (c) they reacted with a polyclonal rabbit anti‐human IgE and (d) they blocked the binding of 125I‐labeled IgE to mAb 75. It was concluded that the rabbit IgG contained aId (RaId) bearing the internal image of heat labile determinants of human IgE. The rosetting of IgE‐coated bovine erythrocytes with FcϵR‐bearing cells was inhibited by preincubating the receptor‐bearing cells with IgG RaId or its F(ab')2 but not with normal rabbit IgG. The ability of RaId to react with IgE‐BF as well as with FcϵR was also shown in inhibition experiments where IgE‐BF and solubilized FcϵR blocked the binding of mAb 75 to RaId. Finally, Western blot analysis of human colostrum, known to contain IgE‐BF, indicated that radioiodinated RaId and IgE identified the same 12‐16‐kDa molecules corresponding to IgE‐BF.

It is concluded that RaId expresses the internal image of a heat‐labile determinant of IgE which is involved in the binding of IgE to IgE‐BF and FcϵR. An alternative interpretation is that RaId reacts with an idiotypic determinant of mAb 75 which is shared by IgE‐BF and FcϵR.
Inhibition of B cell growth factor (BCGF) by monoclonal antibodies directed against the C3d receptor (CR2)
Authors: Perri Robert T. , Wilson Barry S. , Kay Neil E.
Published: February 2007

Normal human B cell proliferation is controlled by various immunoregulatory signals including the T cell‐derived lymphokine B cell growth factor (BCGF). Human BCGF provides the final proliferative signal to normal, activated B cells. We herein show that anti‐CR2 monoclonal antibodies inhibit human B cell responsiveness to purified BCGF. Addition of anti‐CR2 antibody, AB5, was capable of completely inhibiting BCGF‐mediated enhancement of either anti‐μ or staphylococcal protein A‐activated human B cells (191 ± 21 cpm vs. 3942 ± 622 cpm, mean ± SEM). Inhibition of B cell response to BCGF by AB5 occurred in a dose‐dependent manner. Monoclonal antibody anti‐B2, which recognizes the same 140‐kDa glycoprotein as AB5, in comparable concentrations also inhibited B cell responsiveness to BCGF. Monoclonal antibodies of the same subclass (IgG1) showed no inhibitory effect on BCGF enhancement of B cell proliferation. The F(ab')2 fragment of AB5 generated by pepsin digestion was similarly inhibitory as was the intact Ig. ABS‐mediated inhibition was independent of the target B cell state of activation. Both resting and activated B cells (anti‐μ or staphylococcal protein A activated) incubated with similar concentrations of AB5 were unresponsive to BCGF. The abilitv of anti‐CR2 antibodies to block BCGF‐dependent B cell proliferation suggests that occupancy of C3d membrane receptors may result in modulation of B cell proliferation in physiologic or clinical disease states.