bluuebunny/crossref_metadata_2025 huggingface dataset:
Sendai virus‐specific T cell clones. II. Induction of interferon production by Sendai virus‐specific T helper cell clones
Authors: Ertl Hildegund C. J. , Brown Earl G. , Finberg Robert W.
Published: February 2007

Interferon (IFN) was detected upon co‐culture of cloned Sendai virus (SV)‐specific T lymphocyte with SV‐presenting syngeneic stimulator cells. The antiviral activity was defined as IFN‐α, β. The T cell clones, upon contact with antigen‐presenting stimulator cells, stimulated adherent cells present in the stimulator cell population to secrete IFN. Induction of IFN production was independent from interleukin 2 production by the T cell clones.
Superoxide anion production from mouse peritoneal macrophages stimulated with surface‐bound IgG and immune complexes: Adsorption characteristics of IgG in relationship to biological activity
Authors: Kasai Shunji , Akaike Toshihiro , Kunimoto Takehiko , Nitta Kazuo
Published: February 2007

The bridging of IgG antibody molecules by either multivalent antigen or protein A adsorbed to a polymer surface triggers superoxide anion (O) generation from mouse peritoneal macrophages. Macrophages, upon stimulation with IgG adsorbed to a hydrophobic polymer, polystyrene, also significantly generated O. In contrast, soluble IgG did not stimulate macrophages. From these results we speculated that IgG adsorbed to polystyrene produces the same kind of a conformational change in its Fc region as seen in immune complexes, and leads to enhancement of the ability of the Fc region to bind macrophage Fc receptors, acting as a multivalent cross‐linking agent to aggregate the Fc receptors. The surface charge density of the immunosorbent did not affect the antigen recognition function of antibody, but markedly affected its effector function. These findings suggest that activation of the Fc receptor‐mediated function of macrophages requires, on the one hand, optimal conformational change and orientation of IgG and immune complexes adsorbed to the polymer surface and, on the other hand, the bridging of IgG molecules by multivalent agents.
Evidence for the ontogenic precedence of suppressor T cell functions in the human neonate
Authors: Andersson Ulf , Britton Sven , De Ley Marc , Bird Graham
Published: February 2007

The study was undertaken to elucidate some functional characteristics of T cell subsets in human cord blood. A comparison of the cellular interactions involved in the in vitro regulation of pokeweed (PWM) vs. Epstein‐Barr virus (EBV)‐driven B cell differentiation was done in vitro in short‐term cultures of lymphocytes from newborns or adults. T cell subsets were isolated using the monoclonal antibodies OKT4+ and OKT8+.

OKT4+ but not OKT8+ T lymphocytes from adults as well as neonates suppressed EBV‐induced immunoglobulin (Ig) secretion of B lymphocytes from adults. This inhibition was mediated through gamma‐type interferon (IFN‐γ). B cells from newborns were not inhibitable by OKT4+ lymphocytes as a result of their insensitivity to IFN‐γ.

Helper activity for PWM‐induced Ig secretion was exclusively contained within the OKT4+ population from adult T cell donors. This function was normally not detectable in any of the neonatal T cell subsets. OKT8+ cells from both adults and neonates suppressed PWM‐induced Ig secretion, but required the collaboration with cells within the OKT4+ population. The suppressor activity in the PWM system was not IFN‐γ‐mediated.

Thus, suppressor functions for EBV‐vs. PWM‐induced Ig synthesis were mediated through different pathways. There was no evidence of a unique suppressor system in the newborn. In the neonate, suppressor T cell activities are developed before T helper functions, a circumstance for which there is good evolutionary reason.
Biochemical analysis of class II antigens. Identification of a two‐ and a three‐polypeptide chain complex of I‐A locus equivalent molecules in the rat
Authors: Bayer Joachim , Reske Konrad
Published: February 2007

The polypeptide chain composition of class II antigens from LEW rat spleen cells was studied utilizing cross‐reactive mouse alloantiserum A. TH anti‐A.TL (specificity anti‐Iak) and the monoclonal antibodies MRC‐OX6 and MRC‐OX3 for immunoprecipitation. Two‐dimensional gel mapping of A. TH anti‐A. TL immunoprecipitates revealed that, as in the mouse, two groups of class II antigens exist corresponding to I‐A and I‐E locus equivalent structures. In the absence of reducing agents three monomeric chains α, 36 kDa (p36); γ, 33 kDa (p33); and β, 23 kDa (p23), were detected for I‐A equivalent antigens, whereas I‐E equivalent molecules separated into five monomeric chains: α, 37 kDa (p37); γ, 33 kDa (p33); and three β chains 28 (p28), 26 (p26) and 24 kDa (p24). One strong dimer component of disulfide‐linked γ chains was found to be associated with products of both loci. Although slightly different in molecular weight, γ chain corresponds to the nonpolymorphic murine invariant chain Ii.

Both monoclonal antibodies recognized rat homologues of the murine I‐A products. Extensive sequential criss‐cross‐immunoprecipitation with subsequent 2‐dimensional O'Farrell analysis indicated that (a) MRC‐OX6 precipitated molecules which were not recognized by MRC‐OX3 and vice versa; (b) MRC‐OX6 precipitated a three‐polypeptide chain complex composed of the polypeptides p36, p33 and p23; (c) MRC‐OX3 precipitated a two‐chain complex composed of p36 and p23; and (d) the respective heavy (α) and light (β) chains of both complexes possess very similar physicochemical parameters, suggesting that they are structurally related, if not identical.
Evidence for a new lymphocyte‐stimulating determinant (Lsd) detected by alloreactive T cell lines
Authors: Opalka Bertram , Kölsch Eckehart
Published: February 2007

Three alloreactive T cell clones are described which reveal a new lymphocytestimulating determinant (Lsd) controlled by a gene on chromosome 1 of the mouse but different from and possibly centromeric to Mls. Two clones were originally isolated as anti‐H‐2b‐specific and showed and retained cross‐reactivity to Lsd (clone OD3, BALB/c anti‐C57BL/6; clone KB37, B10.BR anti‐C57BL/10). The third clone (BD7, C57BL/6 anti‐CBA/J) was probably originally directed against Lsd. So far, Lsd is only characterized by stimulation of T cell proliferation, and its physiological function is not yet known.
Monoclonal antibodies against HLA‐DR antigens acting on stimulator cells prevent OKT8+ T lymphocytes from acquiring sensitivity to interleukin 2 and expressing suppressor function
Authors: Palacios Ronald , Guy Keith , Van Heyningen Veronica
Published: February 2007

Purified OKT8+ but not OKT4+ T lymphocytes generated suppressor activity in autologous mixed lymphocyte reactions (AMLR) in the presence but not in the absence of interleukin 2 (IL 2) as determined in proliferative responses of peripheral blood mononuclear cells induced by Concanavalin A, the OKT3 monoclonal antibody and allogeneic cells (indicator systems for suppressor activity used in this study). Furthermore, treatment of AMLR‐activated T cells with the OKT8 antibody plus complement abolished suppressor cell activity whereas treatment of the cells with the OKT4 antibody plus complement did not.

The three monoclonal anti‐HLA‐DR antibodies used in this study abrogated the induction, but not the effector phase, of suppressor cells in AMLR. The anti‐DR antibodies acted specifically on the stimulator non‐T cells and not on the responder T cells. The addition of IL2 to AMLR cultures performed in the presence of the anti‐DR antibodies did not restore or increase the suppressor activity whereas IL2 added to AMLR cultures exposed to control antibodies or medium alone increased the suppressor activity. Moreover, purified OKT8+ T cells cocultured with autologous non‐T cells and IL2, in the presence of the anti‐DR antibodies, neither responded to IL2 by proliferating nor expressed suppressor function. In contrast, OKT8+ T cells from similar cultures, but performed in the absence of the anti‐DR antibodies or exposed to control antibodies, proliferated to IL2 stimulation and exhibited suppressor activity. Unactivated OKT8+ T cells were unresponsive to IL2 and unable to express suppressor function. Finally, the addition of the OKT8 antibody (in the absence of complement) to AMLR cultures had no effect on the generation of suppressor cells.

From these results, we conclude the following: (a) OKT8+ T lymphocytes become sensitive to IL2 by interacting with HLA‐DR antigens on the stimulator non‐T cells and, with the help of IL2, they express suppressor cell activity; (b) the OKT8 antigenic determinant on AMLR‐activated suppressor cells does not seem to participate in their process of activation; (c) results of previous studies showing that OKT4+ T lymphocytes become sensitive to IL1 and are capable of synthesizing IL2 after interaction with HLA‐DR on the stimulator cells, and the findings presented here, lead us to suggest that both OKT4+ and OKT8+ T lymphocytes possess receptors for self HLA‐DR antigens and that neither the OKT8 nor the OKT4 antigenic determinants on these cells are involved in the recognition of HLA‐DR antigens. The suppressor activity generated in AMLR may be one mechanism whereby effector self‐tolerance is maintained in the face of inductive self‐recognition.
A spleen‐thymus interaction is involved in the tolerization of thymocytes to xenogeneic erythrocytes
Authors: Bunce Judi V. , Mason Donald W.
Published: February 2007

Previous work has shown that thymocytes of rats receiving two i.v. injections, 4 days apart, of large numbers of xenogeneic erythrocytes become tolerant of the injected cells whereas peripheral T cells in the same recipients make a vigorous response to the injected antigen. Results are herein presented of experiments on the effect of splenectomy on the induction of thymocyte tolerance produced in this way. Splenectomy performed either immediately before the first injection of erythrocytes, or between the two injections, completely prevented tolerance induction and tolerance was still incomplete when splenectomy was performed as late as a few hours after the second injection of tolerogen. Sham splenectomy had no effect on the erythrocyte‐induced thymocyte tolerance. The results demonstrate an essential role for the spleen in the tolerization of thymocytes in this system. Possible mechanisms and the implications for self tolerance are discussed.
Defective induction of antigen‐reactive proliferating T cells in B cell‐deprived mice II. Anti‐μ treatment affects the initiation and recruitment of T cells
Authors: Ron Yacov , De Baetselier Patrick , Tzehoval Esther , Gordon Julius , Feldman Michael , Segal Shraga
Published: February 2007

Mice injected from day of birth onwards with rabbit anti‐mouse IgM (anti‐μ) antibodies were found to be B cell‐deficient and defective for the induction of antigen‐reactive proliferating T cells (TPRLF). This defective induction was not due to the absence of circulating antigen‐specific antibodies since the daily injections of such antibodies during exposure to antigen did not restore the ability of anti‐IgM treated animals to generate TPRLF. Analyzing the cellular events implicated in the induction of virgin antigen‐reactive T cells, anti‐μ‐treated mice manifested impairment of the three interacting cell types involved in the induction of TPRLF. Thus, peritoneal and splenic antigen‐presenting cells from such animals were impaired in their capacity to signal a primary antigen‐specific T cell reaction. Their splenic lymphocytes could not function as initiator cells in transferring immunogenic signals to recruit TPRLF in normal recipients. Potent antigen‐specific splenic initiator cells failed to induce the recruitment of specific TPRLF in anti‐μ‐treated mice. The defective induction of TPRLF in anti‐μ‐treated mice may be due to a functional impairment of cells expressing membranebound IgM molecules which seemingly play a central role in the transfer of immunogenic signals for the recruitment of antigen‐specific circulating T cells. We suggest that splenic B cells function as initiators in the transfer of antigen‐induced signals from peritoneal antigen‐presenting cells to T cells. These seems to be the primary targets of anti‐μ treatment.
A highly conserved determinant on human rheumatoid factor idiotypes defined by a mouse monoclonal antibody
Authors: Pasquali Jean‐Louis , Urlacher Arlette , Storck Daniel
Published: February 2007

Different human IgM rheumatoid factor (IgM RF) idiotypes have been described defined by polyclonal rabbit anti‐idiotypic antibodies. These antisera do not allow clear genetic analysis of the idiotypic determinants, be they cross‐reactive or private. Therefore, we tried to obtain a set of monoclonal anti‐idiotypic antibodies directed against RF idiotypes. Purified IgM RF serum from a patient with classical rheumatoid arthritis was used to immunize BALB/c mice. The spleen cells were fused with Sp 2/0 Ag 14, a nonsecreting mouse myeloma cell line, and a hybrid producing monoclonal anti‐idiotypic antibody was selected. The mouse antibody, an IgG1 x, reacts with an identical or similar determinant located on (or close to) the binding site of all tested monoclonal or polyclonal IgM RF from totally unrelated patients with Waldenströms's macroglobulinemias or rheumatoid arthritis. The monoclonal antibody also reacts with 2 rheumatoid arthritis patients' IgG RF and with a low proportion of normal polyclonal IgM without detectable RF activity. An hypothesis is proposed to explain the existence of a such highly conserved determinant on RF idiotypes.
A human lymphocyte‐associated antigen involved in cell‐mediated lympholysis
Authors: Hildreth James E. K. , Gotch Frances M. , Hildreth Phyllis D. K. , McMichael Andrew J.
Published: February 2007

Human lymphocyte function antigen (HLFA) is a cell surface protein defined by two monoclonal antibodies MHM23 and MHM24. It is present on both B and T lymphocytes but in greater amounts on the latter. Both antibodies precipitated antigen, from radiolabeled HSB‐2 cells, which ran as two chains on sodium dodecyl sulfate polyacrylamide gel electrophoresis at 180 and 94 kDa. Neither antibody inhibited binding of the other, indicating that distinct epitopes were recognized. Both antibodies were shown to inhibit HLA‐restricted lysis of influenza virus‐infected and Epstein‐Barr virus‐transformed target cells by cytotoxic T lymphocytes. Blocking occurred at the level of the effector cells and in the presence of subsaturating concentrations of antibody. Both reagents also inhibited lysis of K562 cells, mediated by natural killer cells. These blocking effects differ from the inhibitory effects of monoclonal anti‐HLA ABC and anti‐suppressor cytotoxic T cell antibodies which inhibit only HLA‐restricted lysis when present in saturating amounts. It is concluded therefore that HLFA is likely to be involved in the nonspecific adherence or lytic functions of killer cells rather than specific antigen recognition.
Clonal anergy: Inhibition of antigen‐driven proliferation among single B lymphocytes from tolerant animals, and partial breakage of anergy by mitogens
Authors: Pike Beverley L. , Abrams Judith , Nossal G. J. V.
Published: February 2007

Mice were injected with fluoresceinated human gamma globulin (FLU‐HGG) either at 2–3 days of age or as pregnant females. At 2 weeks of age, the spleen cells of the injected suckling mice or offspring were fractionated on FLU‐gelatin dishes to yield FLU‐binding B cells. These B cells were then cloned in microcultures using one of two recently described systems in which single B cells grow in the absence of feeder or filler cells, namely following stimulation with FLU‐polymerized flagellin (FLU‐POL) and conditioned media containing B cell growth and differentiation factor(s); or mitogenic activation by a mixture of E. coli lipopolysaccharide (LPS) and dextran sulfate (DxS). As such cultures permit visualization of clonal proliferation as well as ultimate harvesting of cultures for assay of hemolytic plaque‐forming cells, it was possible to ask whether the lesion in the tolerant state affected the B cell's capacity to divide, to differentiate to antibody secretion, or both.

The results indicated that, when stimulated with antigen, the anergic cells could neither divide nor differentiate. However, when the strong mitogen mixture was used, clonal anergy was partially broken. The cells proliferated, and a small proportion of them differentiated into anti‐FLU antibody‐forming cells. A marked variation in antigen‐binding avidity of the FLU‐binding cells made it difficult to quantitate the degree of uncoupling of proliferation and differentiation among tolerant, LPS plus DxS‐stimulated cells. Nevertheless, a partial reversibility of clonal anergy must affect views on mechanisms of self‐tolerance.
Production of human immune interferon (Hu IFN‐γ) studied at the single cell level. Origin, evidence for spontaneous secretion and effect of cyclosporin A
Authors: Palacios Ronald , Martinez‐Maza Otoniel , De Ley Marc
Published: February 2007

A reverse hemolytic plaque assay has been developed which specifically detects secretion of human immune interferon (Hu IFN‐γ) at the single cell level. Unstimulated peripheral blood lymphocytes from healthy adult volunteeers spontaneously secreted IFN‐γ. Stimulation of these cells with concanavalin A, phytohemagglutinin, or the UCHT1 monoclonal anti‐human T cell antibody significantly increased the number of IFN‐γ‐secreting cells. The cell producing IFN‐γ, both spontaneously and after UCHT1 antibody stimulation, is an OKT3+, 4+,8−,HLA‐DR− T lymphocyte as determined at the single cell level. Finally, cyclosporin A, a potent and selective immunosuppressive drug for T cells, strongly inhibited the secretion of IFN‐γ as assayed at the cell level. This IFN‐γ reverse hemolytic plaque assay has great potential for the further study of IFN‐γ both in physiological and pathological conditions.
Detection of interspecies idiotypic cross‐reactions associated with antibodies to hepatitis B surface antigen
Authors: Kennedy Ronald C. , Ionescu‐Matiu Irina , Sanchez Yanuario , Dreesman Gordon R.
Published: February 2007

A common idiotype was defined by a rabbit anti‐idiotypic antiserum generated against human antibodies to hepatitis B surface antigen (anti‐HBs). This idiotype was detected in anti‐HBs from eight different individuals who had been previously infected with hepatitis B virus and is referred to as the CHBs idiotype. The CHBs idiotype was also identified in sera from rabbits, mice, guinea pigs, swine, goats and chimpanzees that had been immunized with hepatitis B surface antigen (HBsAg). Expression of the CHBs idiotype in sera from other species was associated with anti‐HBs molecules. These results suggested that variable‐region genes responsible for the CHBs idiotype have been conserved through long periods of evolution. It was noteworthy that the CHBs idiotype was not detected in the sera of a nonmammalian species, chickens, that had been successfully immunized with HBsAg.
Modulation of B and T cell subsets in mice treated with fractionated total lymphoid irradiation. III. Spleen and thymus dependency of B cell maturation processes
Authors: Zan‐Bar Israel
Published: February 2007

The role of spleen and thymus in maturation processes of B cell subpopulations was examined using mice which underwent fractionated total lymphoid irradiation (TLI). (BALB/BL)F1 mice received 200 rds lymphoid irradiation daily for 8 days. Mice were spleen‐shielded or ‐unshielded, or thymus‐shielded or ‐unshielded during the irradiation. One day after termination of the irradiation, TLI‐treated unshielded mice were reconstituted with 10 × 106 spleen, thymus or bone marrow cells of normal untreated syngeneic mice. Two and a half months after termination of the treatment, the ability of the treated mice to produce in vivo anti‐trinitrophenyl (TNP)‐Ficoll antibodies, and the capability of spleen cells of those mice to respond in vitro to dextran sulfate and lipopolysaccharide was checked. In parallel, stained spleen cells were analyzed on the fluorescence‐activated cell sorter. The results indicate that B cell maturation occurs only in mice where the spleens were shielded during TLI‐treatment or in TLI‐treated mice reconstituted with spleen cells of normal untreated mice. In these mice, the light scatter and the fluorescence distribution profiles were the same as those obtained from spleen cells of control mice: the treated mice gave a high anti‐TNP‐Ficoll antibody response and the proliferative response of the cells was low to dextran sulfate and high to lipopolysaccharide.

Thymus shielding during TLI treatment or reconstitution of TLI‐treated mice with thymus or bone marrow cells could not abolish the blockage of B cell maturation processes. These findings indicate that the spleen plays an obligatory role in B cell subset maturation pathways, whereas the thymus appears to play no essential role in these processes.
Quantitation of anti‐NP (4‐hydroxy‐3‐nitrophenyl)‐acetyl idiotype expression on spleen and thymus cells
Authors: Wall Katherine A. , Frackelton A. Raymond , Reilly Edward B. , Azuma Takachika , Chang Tse‐Wen , Eisen Herman N.
Published: February 2007

Direct binding of 125I‐labeled rabbit anti‐NPb idiotype antibodies (RaId) was used to quantitate the expression by immune spleen and thymus cells of NPbId, the characteristic Id of the λ1‐containing antibodies made by C57BL/6 (B6) mice to the (4‐hydroxy‐3‐nitrophenyl)acetyl (NP) group. Direct binding of RaId by B and T cell preparations reached a maximum of 12 ng RaId per 108 cells at 7 days after immunization. Spleen T cell preparations maintained similar levels of binding after positive selection for Thy‐1.2+ cells and overnight culture. RaId binding was also demonstrated for immune B6 thymus cells and for spleen and thymus cells of immune SJL mice, which have the appropriate heavy chain allotype for NPbId expression but have only barely detectable serum Id. However, the NPbId of T and B cell preparations were indistinguishable by (a) the susceptibility of RaId binding by the cells to inhibition by hapten or by antibodies to the variable regions of λ light chains (anti‐Vλ) and by (b) the ability of anti‐Vλ and of monoclonal antibodies to the constant region of λ1 chains (anti‐Cλ1) to immunoprecipitate antigen (NP10‐bovine serum albumin)‐binding proteins from detergent extracts of isotopically labeled cells. The results strongly imply that virtually all of the NPbId of T cell preparations is due to conventional NPbId antibody that is tightly bound to T cells. The results do not, however, exclude the possibility that the T cell preparations contain a trace amount (≤ 1 ng/108 cells) of unusual NPbId‐like molecules that lack λ chains.
A monoclonal antibody against a new differentiation antigen of thymocytes
Authors: Sidman Charles L. , Forni Luciana , Köhler Georges , Langhorne Jean , Lindahl Kirsten Fischer
Published: February 2007

B14−2−14 is a monoclonal cytotoxic IgM antibody which reacts with thymocytes of all mouse strains tested. The fraction of positive cells (by visual immunofluorescence) varies between strains from about 25–45% in A. CA to 65–85% in C57BL/6, and high levels are dominant in F1 hybrids. In the periphery, the antigen is found on a few percent of lymph node and not on splenic T cells, and it is absent in nude mice. Among thymocytes, the distribution of the B14 determinant largely overlaps with that of the TL antigen and of molecules binding peanut agglutinin. The B14 antibody reacts only minimally with hydrocortisone‐resistant thymus cells. Biochemical analysis shows that B14 antibody, anti‐TL antibody and peanut agglutinin bind to separate molecules. The target of the B14 antibody may be either an immature, thymic form of Thy‐1, or another molecule associated with it. Two polypeptides, of 40 and 35 kDa are precipitated by both B14 and anti‐Thy‐1 antibodies from biosynthetically labeled thymus cell lysates, and two others, of 27 and 17 kDa, from surface‐iodinated thymus cell preparations. B14‐2‐14 offers an additional method for identification and selection of thymocytes at different stages of differentiation, and should also be useful for studies of the Thy‐1 antigen.
Specific in vivo and nonspecific in vitro alloreactivities of adult frogs (Xenopus laevis) that were thymectomized during early larval life
Authors: Nagata Saburo , Cohen Nicholas
Published: February 2007

Thymectomy of very young Xenopus larvae abrogated in vitro proliferative responses to phytohemagglutinin (PHA) and allogeneic leukocytes. Thymectomized (Txd) frogs, however, still rejected first‐set skin allografts chronically and second‐set grafts (but not third‐party grafts) more rapidly. The specific second‐set rejection reaction by Txd frogs was transferable in vivo to secondary Txd hosts (with major histocompatibility complex identical to the cell donor) by the subcutaneous injection of a mixture of splenic and peripheral blood leukocytes. Spleen cells used in this adoptive transfer experiment (i.e., immune cells) were responsive to allogeneic cells from the original donor strain as well as from unrelated donors in mixed leukocyte culture in vitro but were still unreactive to PHA. The results are consistent with an extrathymic pathway of alloreactive cell differentiation in this species, although the physiological significance of such a pathway is not clear.
Characterization of the cytolytic activity of a cloned antigen‐specific T suppressor cell derived from a tolerant CBA/J mouse
Authors: Heuer Joachim , Opalka Bertram , Rassat Jürgen , Themann Hermann , Kölsch Eckehart
Published: February 2007

The antigen‐specific T suppressor cell clone HF1 isolated from a CBA/J mouse made tolerant by low doses of bovine serum albumin has suppressive and cytolytic activity. The analysis of the latter gave the following results. Natural killer (NK)‐sensitive YAC‐1 (H‐2a) and RBL‐5 (H‐2b) target cells are lysed whereas other NK targets, like EL4 (H‐2b) or the human K562 cell line are resistant. Cytolytic activity is not antibody mediated. Its inhibition by sugar phosphate or monoclonal antibodies against LFA‐1 antigens is such that HF1 can neither by typed as T killer nor as NK cells. It seems to represent a distinct T lymphocyte type.
Genetic control of the response of chicken T lymphocytes to concanavalin A: cellular localization of the low responder defect
Authors: Pink J. Richard , Vainio Olli
Published: February 2007

Genetic variation in the response of chicken lymphocytes to the T cell mitogen concanavalin A (Con A) has previously been studied by assaying tritiated thymidine ([3H]dThd) uptake of cultured cells following mitogen stimulation. Our present results show, firstly, that low [3H]dThd uptake (e.g. in cultures of Con A‐stimulated cells from low responder CB, CC or G‐B1‐lo birds) is correlated with low proliferative activity and with reduced capacity to form Con A‐dependent T cell colonies in semisolid agar. Secondly, in cultures containing mixtures of cells from high and low responder birds, the cells from each partner respond independently to Con A (there is neither suppression of high responder, nor activation of low responder cell proliferation). Finally, Con A‐stimulated cultures of high responder cells respond better to T cell growth factors, as well as producing more growth factor activity, than cultures of low responder cells. These results suggest that the basis for the low responder phenotype is an intrinsic inability of low responder T lymphocytes to respond to Con A by differentiating into growth factor‐sensitive blast cells.
The role of accessory cells in polyclonal T cell activation II. Induction of interleukin 2 responsiveness requires cell‐cell contact
Authors: Hünig Thomas
Published: February 2007

It has previously been reported (Hünig, T. et al., Eur. J. Immunol. 1983. 13: 1) that highly purified peripheral T cells do not respond to concanavalin A (Con A) even in the presence of Con A‐induced spleen cell supernatant as a source of interleukin 2 (IL2). In the present report, the hypothesis was tested whether this unresponsiveness correlates with the observed inability of Con A to mediate cell‐cell contact between highly purified T cells. It was found that T cells, pretreated with neuraminidase to reduce their net negative charge, were both aggregated and rendered IL2‐reactive by Con A. In addition, leukoagglutinin (LA) was found to be able to both agglutinate untreated T cells and to make them IL2‐reactive. Neuraminidase treatment reduced the concentration of LA required to mediate both effects. Neuraminidase treatment did not alter the overall Con A‐binding capacity of T cells, nor did it induce reactivity to IL2 in the absence of lectin. Furthermore, irradiated, neuraminidase‐treated T cells served as accessory cells (AC) in the induction of responsiveness to IL2, but not for production of IL2, which depends on Ia+ AC. Finally, Lyt‐2− neuraminidasetreated peripheral T cells responded in the same fashion as whole T cell populations, indicating that at least some T cells of the helper phenotype need not interact with Ia+ AC for the induction of IL2 responsiveness.
The evolution and involution of Peyer's patches in fetal and postnatal sheep
Authors: Reynolds John D. , Morris Bede
Published: February 2007

The Peyer's patches (PP) of sheep have a number of important anatomical features and functional characteristics which are similar to tissues that have been classified as primary lymphoid organs. The prenatal maturation of PP occurs in the absence of any antigenic stimulus as immunogenic molecules are not normally encountered by the sheep fetus. Primordial PP were first detected in the small intestine of fetal sheep at about 60‐days gestation; lymphoid follicles were present by 75‐days gestation and vigorous lymphopoiesis was occurring in these follicles by 100 days. From 120‐days gestation until birth, at about 150 days, the PP follicles were histologically mature and they had the greatest density of proliferating lymphoid cells found anywhere in the body. The total number of PP and their constituent follicles had developed before birth when there were 25–40 discrete PP in the jejunum and proximal ileum and one single continuous PP in the terminal ileum. There was no evidence of any change in the rate of growth of the PP follicles at birth which could be related to the advent of the first antigens in the gut.

The total weight of PP tissue was greater than any other single lymphoid tissue by about 6 weeks after birth weighing around 120 g or about 1.2% of the body weight; about 50–60 g of the PP tissue was calculated to be lymphoid tissue. At this time the ileocecal PP (IPP) extended 2.5 m along the terminal ileum and accounted for about 90% of the total mass of PP.

From about 12 weeks after birth the IPP began to involute and only a few PP follicles remained in this region of the intestine by 18 months of age. Follicles in PP in other parts of the small intestine remained and continued to produce lymphocytes throughout the life of the animal.

PP contain a number of anatomically and functionally distinct lymphoid compartments that could play different roles in the body's immune defense. Explicit in most theories on the function of PP is the notion that antigenic stimulation is the cause of the lymphopoiesis in the follicles; our results do not support this view. Instead they suggest that the follicles in the PP of sheep may play a role similar to that played by the bursa of Fabricius in birds.
Disappearance and reappearance of high endothelial venules and immigrating lymphocytes in lymph nodes deprived of afferent lymphatic vessels: a possible regulatory role of macrophages in lymphocyte migration
Authors: Hendriks Hans R. , Eestermans Inge L.
Published: February 2007

Interruption of the afferent lymphatic vessels of the popliteal lymph node resulted in the disappearance of high endothelial venules (HEV) and immigrating lymphocytes within 3 weeks. HEV showed several characteristic morphological changes: the endothelial cells became flattened and less pyroninophilic, the chromatine became condensed and protein synthetizing and secretory cell organelles became scarce. At the same time the number of macrophages in the lymph node was severely reduced. Injection of sheep red blood cells into such lymph nodes, 6 weeks after operation, resulted in reappearance of HEV and immigrating lymphocytes, and development of many plasma cells and some germinal centres. Injection of lipopolysaccharide into the operated lymph nodes resulted in the appearance of many plasma cells and a few poorly developed germinal centres; HEV and immigrating lymphocytes, however, remained almost absent.

The results show a relationship between the immigration of lymphocytes and the activity of the endothelial cells in the HEV. The activation of the latter may occur by mediators released by antigen‐stimulated macrophages and T cells. Moreover, the morphological features of the HEV are independent of the presence of recirculating lymphocytes.
Ultrastructural characteristics of human T cell clones with various cytolytic activities
Authors: Grossi Carlo E. , Zicca Antonio , Cadoni Angela , Mingari Maria C. , Moretta Alessandro , Moretta Lorenzo
Published: February 2007

Fifteen T cell clones with different (specific, antibody‐dependent or natural killer‐like) cytolytic activity were derived from mixed lymphocyte culture activated T cells and analyzed for their morphological characteristics and, in some instances, for their surface markers.

All of the five cytolytic clones analyzed by electron microscopy possessed numerous electron‐dense granules and in some instances multivesicular bodies, with or without an electron‐dense matrix, that are the putative precursors of the granules. In addition, light microscopy examination of semithin sections of other ten cytolytic clones showed that the large majority of the cells in each clone had numerous toluidine blue‐stained cytoplasmic granules. It is of note that nine clones without detectable cytolytic activity analyzed by electron microscopy did not possess granules and presented the features of large agranular blasts. Ten cytolytic clones were analyzed for different surface markers including rosette formation with sheep erythrocytes (E rosettes), receptors for the Fc portion of IgG or IgM (FcγR and FcμR) and a group of antigens recognized by monoclonal antibodies including Ia, 4F2, OKT8 or OKT4. All the clones were Erosette+, Ia+ and 4F2+. Expression of FcγR was restricted to the clones active in antibody‐dependent cell‐mediated cytotoxicity. Expression of OKT8 and OKT4 antigens was variable; in particular, five clones were OKT8+/OKT4−, whereas the other five expressed the OKT8−/OKT4+ phenotype. It is noteworthy that the ultrastructural features of cytolytic T cell clones are similar to those of large granular lymphocytes, known to be the only lymphoid cells in normal peripheral blood which possess cytolytic activity. Thus, it is possible that the presence of electron‐dense granules may represent a morphological marker for all human cytolytic lymphocytes.
Thymic reticulum in mice III. Phagocytic cells of the thymic reticulum in culture secrete both prostaglandin E2 and interleukin 1 which regulate thymocyte proliferation
Authors: Papiernik Martine , Homo‐Delarche Françoise
Published: February 2007

A phagocytic cell of the thymic reticulum in culture (P‐TR‐C) has recently been isolated whose characteristics closely resemble those of the thymic interdigitating cell despite the modifications induced by culture conditions.

In the present report it is demonstrated that this cell population is able to produce both interleukin 1 (IL1) and prostaglandin E2 (PGE2). IL1 has no direct mitogenic effect on thymocytes but is comitogenic with concanavalin A. PGE2 has no direct effect on the secretion of IL1 by P‐TR‐C, but has an effect antagonistic to IL1, inhibiting thymocyte proliferation. P‐TR‐C are thus able to modulate thymocyte proliferation in vitro.
Synthesis of λ light chain subtypes by stimulated and unstimulated mouse B cells
Authors: Onodera Yoshimitsu , Reilly Edward B. , Eisen Herman N.
Published: February 2007

Inbred mouse make 3 λ chain subtypes. The λ1 and λ3 chains have similar variable (V) regions (in both the same V gene segment [Vλ1] is used), whereas λ2 and λ3 have similar constant (C) regions. Despite the λ1 and λ3 V region similarity, λ1 occurs much more frequently than λ3 (and λ2) in the serum immunoglobulins and antibody responses of most inbred strains of mice. To explore the basis for the λ1 predominance, we compared the rates of synthesis of the 3 subtypes and the frequencies of the B cells that synthesize them, focussing on “resting” (i.e., unstimulated) and on polyclonally stimulated B cells from spleens of unimmunized BALB/c mice.

In resting cells the relative rates of synthesis and the relative frequencies of the respective B cells were in accord, indicating that the rate of λ chain synthesis is approximately the same per resting B cell, regardless of the λ subtype it produces. However, in the polyclonally stimulated cells, λ1 was made 7 times faster than λ2 and 10 times faster than λ3; normalizing these rates by the frequencies of the respective stimulated cells suggests that in stimulated B cells λ1 chains are made 5 times faster per cell than λ2 or λ3, while the latter are made at about the same rate per cell. In view of the marked structural homology between λ2 and λ3 genes in segments other than the V‐gene segment, we suggest that the pronounced differences among polyclonally stimulated B cells in expression of the genes for the various λ subtypes may be due to the presence of less potent enhancer‐like sequences in the λ2 and λ3 genes than in the λ1 gene.
Epitope specificity and Ia restriction of T cell responses to insulin in a system of complementing Ir genes: analysis with primed lymph node T cells and a long‐term cultured T cell line
Authors: Spaeth Eberhard , Rüde Erwin
Published: February 2007

The antibody response of (H‐2b × H‐2k)F1 mice to pig insulin (PI) has previously been shown to be under the control of H‐2‐linked, complementing Ir genes. In addition, this response was reported to depend on the genetic background of the parental strains (Keck, K., Eur. J. Immunol. 1977. 7: 811). Here it is demonstrated that the secondary in vitro response of proliferating T cells shows the same dependence on H‐2‐linked Ir genes yet an influence of the background genes could not be detected. The complementing genes were mapped to the Kb, I‐Ab and Kk, I‐Ak regions. For restimulation of F1 T cells by PI, the Ir genes of both parental chromosomes have to be expressed in the same antigen‐presenting cell, suggesting complementation at the molecular rather than at a cell interaction level. With a long‐term cultured, PI‐specific T cell line (ST2) of (B10 × B10.BR)F1 origin the complementation data could be confirmed by mapping the Ia restriction elements to Kb, I‐Ab and I‐Ak. The reactivity pattern of this line towards species variants of insulin and the isolated A and B polypeptide chains in the presence of syngeneic accessory cells suggests that the glutamic acid residue in position 4 of the A polypeptide chain (Asp in mouse insulin) is essential for recognition in conjunction with an (I‐Ab × Ak)F1 hybrid Ia complex. I‐Ab‐encoded molecules carrying specificity Ia. W39 which, according to Rosenwasser, L. J. and Huber, B. T. are essential for the presentation of BI to (CBA/N × C57BL/6)F1 T cells, are not required as components of the F1‐unique restriction element recognized by the F1 T cells of the ST2 line in conjunction with PI. This is indicated by the fact that accessory cells of (CBA/N × B10)F1 hybrids, regardless of their sex, could present PI as well as beef, sheep and horse insulin to the F1‐restricted ST2 cells.
Antibodies specific for different T15 idiotopes induce neonatal suppression of the T15 idiotype
Authors: Berek Claudia
Published: February 2007

The response of BALB/c mice to Pneumococcus pneumoniae is dominated by a single idiotype defined by the phosphorylcholine‐binding myeloma protein TEPC15 (T15). Injection of newborn BALB/c mice with antibodies to the T15 idiotype will lead to suppression of this idiotype. Such mice will respond to the antigen Pneumococcus, but with idiotypically different anti‐phosphorylcholine antibodies. In an attempt to further characterize the effect of anti‐idiotypic antibodies on induction of tolerance, three monoclonal antibodies specific for different T15 idiotopes were used. Although these antibodies belonged to the mouse immunoglobulin classes, IgG1 or IgG2a, and were derived from different mouse strains, in all cases, a long lasting suppression could be induced. The data show that injection of idiotope‐specific antibodies will suppress the T15 idiotype, but not necessarily the idiotope itself. The results are discussed in terms of the mechanism which will lead to the suppression of a dominating idiotype in the newborn mouse.
The immunomodulatory effect of anti‐Micrococcus luteus antibodies I. Effect on in vitro rabbit T cell functions
Authors: Vaeck Mark , Grooten Johan , Hamers Raymond , De Baetselier Patrick
Published: February 2007

A range of purified rabbit anti‐Micrococcus luteus antibodies (anti‐MCAb) were tested for their ability to interfere with a variety of in vitro immune responses. Such antibodies strongly inhibited the secondary IgG antibody response to sheep red blood cells without affecting the IgM response or the proliferative responses to mitogens and antigens. By exposing lymphocyte populations to anti‐MCAb, it was found that such reagents exerted a strong mitogenic effect on rabbit T lymphocytes, provided these cells were derived from antigen‐activated lymph nodes. This mitogenic effect was also obtained with F(ab')2 fragments of anti‐MCAb and with hybridoma‐derived anti‐MCAb. Collectively, these data indicate that anti‐MCAb inhibit the initiation of IgG synthesis possibly through the expansion of immunoregulatory T cell subsets.
Detection in vivo 6 hours after immunization of a mediator with possible antisuppressor activity
Authors: Al‐Maghazachi Azzam , Lee Sho‐Tone , Paraskevas Frixos
Published: February 2007

Immunization of mice with foreign proteins or particulate antigen induces the formation of immunoglobulin (Ig)‐antigen complexes which are strongly cytophilic for T cells and have been shown recently to markedly enhance the 7 S antibody response. In this report we demonstrate that pretreatment of the animals with cyclophosphamide or anti‐I‐J antiserum eliminates the difference in the antibody response between the mice injected with the complexes and the controls, in other words, the enhancement. Six hours after allogeneic stimulation the serum of mice contains also a cytophilic (for T cells) Ig which most likely represents, as in the case of the foreign antigens, complexes of Ig with alloantigens. The allogeneically induced 6‐h serum (6HS) contains a factor which enhances the cytotoxic T lymphocyte(s) (CTL) response in vivo. As with the 7 S antibody response, pretreatment of mice with cyclophosphamide, in doses known to eliminate suppressor cell expression, “masks” the CTL enhancement of the allogeneically induced 6HS. The same result was also observed with the anti‐I‐J antiserum.

In conclusion, the 6‐h complexes in cyclophosphamide‐ and anti‐I‐J‐treated mice do not produce a 7 S antibody or CTL response above that produced by the control group (no complexes).

Using heat‐treated allogeneic tumor cells, known to induce suppressor cells in vivo, we have shown that for a low dose of tumor cells, the allogeneically induced 6HS did not block the induction of suppressor cells, but completely blocked their function. These results suggest that the enhancement of both humoral and cell‐mediated immunity by the 6HS (complexes) is likely to be due to interference with normal suppressor cell function, that is, an antisuppressor mechanism.
Regeneration and the immune system II. Suppressor activities of lymphocytes activated in vivo by liver regeneration and their genetic control
Authors: Yokomuro Kozo , Miyahara Seiko , Takahashi Hidemi , Kimura Yoshitami
Published: February 2007

The lymph node cells (LNC) activated in vivo by liver regeneration following partial hepatectomy of mice (primed lymph node cells) respond to regenerating liver cells in vitro with typical secondary immune response characteristics (Miyahara, S. et al., Eur. J. Immunol. 1983. 13: 878). These LNC activated in vivo suppress the proliferation of responder lymphocytes cultured with mitomycin C‐treated regenerating syngeneic liver cells (sMLHLR). The suppressive activity was already present in LNC 4 days after partial hepatectomy and remained unchanged for at least 16 days. These primed LNC were effective not only on sMLHLR but also on syngeneic mixed lymphocyte culture (sMLR) and allogeneic mixed lymphocyte culture, of which responder cells share the I‐A (I‐B) subregions of the major histocompatibility complex (MHC) with primed LNC. At least one cell in the suppressor circuit is a T cell. The primed LNC restimulates in vitro with regenerating liver cells (in vitro reactivated primed LNC) suppressed the proliferation of syngeneic responder cells in sMLR, but not of cells from congeneic mice differing from the in vitro reactivated primed LNC at a cluster of genes linked to the Ig locus. Thus the suppressive activity of primed LNC is controlled by the I‐A (I‐B) subregions of the MHC and that of in vitro reactivated primed LNC by genes in the Ig region. The role of these suppressive cells in liver regeneration is discussed.
Rabbit leukocyte surface antigens defined by monoclonal antibodies
Authors: De Smet Walter , Vaeck Mark , Smet Erik , Brys Lea , Hamers Raymond
Published: February 2007

Several monoclonal antibodies (mAb) against rabbit leukocytes were characterized in binding and functional studies. mAb 1.24 stains thymocytes, bone marrow cells, peripheral T and B cells and blood monocytes. T cells express more 1.24 antigen than B cells. In the absence of added complement (C), mAb 1.24 inhibits alloantigen‐, concanavalin A (Con A)‐, and phytohemagglutinin (PHA)‐, but not pokeweed mitogen (PWM)‐ or anti‐immunoglobulin (Ig)‐induced cell proliferation. It also strongly blocks anti‐sheep erythrocyte plaque‐forming cell responses. A second mAb, designated 4.B9, binds to 20% of thymocytes and to most, if not all, peripheral T cells and in vitro‐activated T cell blasts. A third one, 10.B3, is reactive with the nearly entire thymocyte and a major peripheral T cell population. Two‐color membrane immunofluorescence reveals the presence of a small population of peripheral blood leukocytes which bear surface Ig and are weakly stained by mAb 4.B9 and 10.B3. Without C, both 4.B9 and 10.B3 inhibit Con A‐ and PHA‐induced mitogenesis, but have no effect on PWM‐, antigen‐, or alloantigen‐induced cell proliferation. Depletion of 4.B9+ cells by panning or complement lysis completely abrogates proliferative responsiveness to antigen and alloantigen, significantly reduces responsiveness to the T cell mitogens Con A and PHA, but enhances that to the B cell mitogen anti‐Ig. A fourth mAb, 12.C7, binds to 60% of thymocytes and to 10–30% of peripheral T lymphocytes at high‐level fluorescence. T cell blasts obtained in mixed leukocyte reactions are partially stained by mAb 12.C7, while those obtained after Con A or PHA activation are not. In addition, mAb 12.C7 is completely unreactive with B cells or monocytes. Without complement, it does not seem to interfere with any of the in vitro functions tested. All antigens studied here do not appear to be expressed in nonleukon tissues, as they do not bind to erythrocytes and are absent from brain, heart, liver and kidney as shown by quantitative absorption analysis.